Thank you for sharing this information. I have been trying to make a working Velomobile design. It's very hard to find people willing to share their concepts.
Try to find a blueprint for the original tilting sidecar on 20s-30' s Harley- Davidson rigs. I can't recall any more if that was a Harley or tilt- car patent. But talk to your local librarian, that's what they do... Find obscure source's of data in places you and I will never think of. Good luck + I'll catch you later.
Hi, I'm doing a similar exercise so thanks for posting this. What I am looking into is different tilt on the wheels, less on the outside of the turn and more on the inside, making the imaginary lines through the wheel axles meet in the centre of the turn.
For ages I been "planning" to make a EV trike 1+1 in tandem with motorcycle parts, but, since i didnt have the time space or money im seriulsy thinkin a electrically assisted trike bike to start with, this exercise was really very informative. thanks
@14:15. Could the straight vertical strut that the wheel mounts to be dished inwards? That might be easier than dishing the wheel? And if you placed the vertical strut behind the axle connection then you can add in some castor and potentially tuck the wheel in even further. Looking at my GoKart chassis as an example the offset and castor are adjustable according to the grip required on the day.
Yes I think that would all be possible. The important thing is the relative location of the pivots and the steering geometry. Once this is all decided, the parts themselves can be designed accordingly.
Have you considered pushing the ideal geometry mechanism to the front or back of the wheel instead of on top? The horizontal bars would require quite some torsional rigidity but it would help with keeping it out of sight of the rider, keeping the body mounting points low and keeping the wheel size unconstrained.
I haven’t put much thought into that option, but would certainly be worth considering! Simplicity and minimising weight would be a good test of success.
Fourteen minutes very well spent, been considering this and the problems that arise for some time now, out of interest how big a problem is tyre scrub and if you mounted the lower arm where it met the tyre slightly higher and angled the wheej outwards, (positive camber), would that be of benefit,
Muchas gracias por todas sus explicaciones. Me encanta este diseño, pero en suramérica son muy poco empleados y las rutas para bicicletas no son muy seguras.
Pretty cool. When ever I’m designing new machines. I always do cardboard and push pins. Works a treat and makes for real easy adjustments. Can’t wait to see what you build.
@Metal Machine Shop This appears to be the most comprehensive coverage on the subject on this platform. Congrats for that. No doubt many hope that this project comes to fruition and viewers get more information helpful to constructing the proposed vehicle. It is very curious that little is now heard of the much praised "Velotilt" trike with two rear wheels, first heard of about 2012. It looked so promising, while it's apparent absence from the market place suggests that it is still overcoming problems. Any light you could shed on this matter would be much appreciated. I look forward keenly to follow ups on this project. I am surprised that the topic of a leaning velo is not far more popular.
Thanks for the comment! I'm not sure what happenend to the Velotilt, I haven't found any up-to-date news on the internet. Nice looking machine though. It uses a different sort of tilting mechanism that I didn't cover in my video.
I'm still working on the design so I'm not sure whether I will ever build it. Once the design is finished maybe I will share it with the velomobile community to see whether it's good enough to build! I'll try to upload another video in due course.
Fantastic piece of analysis! I've done most of this thinking before but without the pretty cardboard aided design. I don't have an aversion to FWD, so the image you showed of the tilting delta trike was right up my street.
very interesting, perhaps you could use the buddy it self (a shell like) to transfer horizontal forces across. Could not see very clear the relationship to the driver's geometry.
This was very helpful. I did find success with slight separation with of the arms from the center point and using the t model but the t shape is just about 1/3rd the height of the space between the upper and lower arms. The points where the shocks connect to the t is the same as the inner pivot points of the arm. Then using the distance for the shock to measure out where it would attach to the lower arm. For body wise you may have to make a slight deviation in the body to allow room for the shocks which aerodynamically shouldn’t effect it to much. You can also prevent a lot of aerodynamic loss by using fine bristles on the slits which will allow it to essentially close the slit.
My experience is the same. 3D CAD takes the design to a next level. From my purely digital work I learned that a powered or at least partially powered vehicle is necessary to achieve gains from the heavy tilting mechanism.
This is a very interesting video with a range of possible designs. The only thing I would say is you are having the single wheel on the same plane as the other two. As the single wheel is at least three/ four feet behind or in front of the other two the amount of scrub or lift can be ignored due to this change in the plane!
Do the two front wheels have to be beside the front of the body? If you moved them forward of the nose, they could be closer, and stay within the frontal area of the body. They could be two feet apart, providing stand-still stability, and faired individually for aerodynamic flow onto the nose. In addition, the nose would not restrict the vertical turning of the two wheels. You could employ a tilt mechanism to your handle bars, along with a standard rotating system for tighter corners. With the wheels close together, you could suspend them with a central shock.
Hi, they don’t have to be beside the body. In moving them forwards you would be trading length overall for reduced width but you are right, the steering wheels could be closer together which would be good. You would need to allow clearance for the frame/chassis.
Very interesting. Have you thought about running the tilt mechanism on the rear and using FWD? This would ease packaging and obviate the need for a differential.
me gusto mucho la excelente explicación y los diferentes modelos y problemas que presentan, han sido de una gran ayuda para mi, quería sugerir en cuanto a la suspensión, porque no colocas un pequeño sistema de suspensión en cada rueda, igual que la que usas en la central y que cada rueda suspenda por individual, te voy a enviar un modelo de suspensión sencillo que usa una trike bike, buscare el link del vídeo y te lo comparto en otro msj
That was excellent, Bravo!!! I build gravity racing vehicles and I have always thought a tilting suspension would be amazing, thank you for sharing such a vast amount of time and work!
really like your evaluation, trail and error. where the center joints come together , please consider sliders that cross before connecting to shocks? thanks
Would it be possible to have a design with the front wheels at a slight angle instead of them being orthogonal to the ground? At 5:18 you mention that one of the problems is that the lower pivot points of the parallellogram are offset relative to the contact point of the tires on the ground, creating a triangle that lowers the outer pivot and raising the inner pivot. If the wheels were angled inward at the bottom, it should be possible (geometrically) to lessen or completely eliminate this triangle. Disclamer: I'm not an engineer and neither did I play around with pivoting models, so I suppose there are very likely some indesirable consequences that I forgot about. Indesirable consequences I can think of myself is that the angle will cause the velomobile to broaden at the top of the wheels and the velomobile riding continuously on the side of the tires and/or wheels, which they were not designed for.
Yes I guess you could do that but adding camber to the wheels could add a slight sideways force to the tyre rather than keeping the weight directly down through the centre of the wheel and tyre.
what are your thoughts on using driveshaft instead of chain? like the focus on efficient performance. solid work. good luck. if i sacrificed any efficiency it would be to (pun alert) lean toward larger wheels for smoother ride.
It can be done. I’ve seen a hire bike with a drive shaft. You would need hub gearing rather than normal bike gears. On my recumbent velomobile design, you would need a couple of universal joints to route the shaft around the rider, plus extra supporting bearings. Shaft drive would be a bit less efficient than chain, but could be enclosed more easily. I also found on my velomobile design that smaller wheels were needed to give steering clearance and to keep the overall length within reasonable limits. I talk about this in one of my other videos. Enjoyed the pun lol!
Few people today recall that the first Harley- Davidson side hacks we re of a tilting design. H- D didn't make them, that was a contract with a private co. During WW 11, the company made bus replacement parts. Afterwards that company was still in business, Nowadays they make the tilting platform buses in Los Angeles California.
Interesting video with a lot of thought in it. However, I suspect the problem is even more complex than it appears in this video. I think the problem also needs to be considered 3 dimensionally, and not just 2 dimensionally as presented here. Notice in particular the camber angles of the wheels relative to each other while in a lean as would be experienced in a turn. Each wheel is in a slightly different turn radius and should require a different camber than the other wheel. The inside wheel in a turn should have less camber than the outside wheel.
Does camber directly relate to local turning radius? Or are you recommending a camber angle/ turning radius relationship for wear characteristics or handling?
I like your very detailed analysis, but I am still confused by what controls the tilt to happen. Is tilt controlled by the rider's balance or is tilt controlled by the steering mechanism. I would imagine if tilt was a summed result of (steering and speed) or (centripetal force) then tilt stability would be constant of (center of gravity). Could a pendulum pivoting on a disk (where the disk acts like the horn of a servo) and push rods from that disk control the tilt help? (The rider could be the weight of the pendulum) What about housing the wheels in a shroud like airplane landing gear? That way, you can have a pivot point in the center of the wheel.. Maybe something as simple as a bike fork that is horizontal instead of vertical, sort of like a gimbal in a gyroscope. (Where tilt and steer are the 2nd and 3rd axises) I think there is a gimbal in the rotor of a helicopter blades.. That is kind of what I am imagining.
I forgot to add..(I'm not sure if this was what you were talking about.) The turn radius of the wheels for inside and outside of the turning curve are different. The inside curve wheel turns to a sharper angle.
Hi, the theory is that the tilting is completely passive. The trike balances in the same way as a bike, the mechanism described just allows the tilting to happen, only on three wheels not two.
My thoughts were how to make it so that the center of gravity is controlled by the centripetal force of the turn, so that the bike auto-tilts to the right angle for the speed and turn radius you are doing. Thus making the bike self balancing.
Amazing, I’d love To make a trike and this is so interesting, what happens if you have the passenger body volume tilt more than the wheels? Eg at 45deg the wheels are at 30 deg. Is that rideable? Really cool channel and presentation, subbed thanks!
Thank you MMC, very very interesting, you saved me a lot of work. One mechanism you didn't try was two pivot points in the center on the lower arms and one on the top, the same they use on the Quadro, do post another video if you try this geometry please. Thanks again for going to all this trouble.
Thanks! I think the Quadro design as you describe it would make the wheels angle outwards slightly relative to each other as the machine tilts or suspension compresses. The effect would be greater the further apart the bottom pivots are. I’m not sure what the advantage of this would be, but the Quadro seems to work pretty well!
MMS, I solved the above problem I discussed in my previous post (Quadro) simply by using your number 4b and turning it upside down, it would have the same result, I'm just wondering how Quadro solved this or didn't they ???? Correct me if I'm wrong but to have the correct geometry the top and bottom pivot points would have to have be aligned in the center such as in figure 2a.
Do let us know how you solved the steering, for your project. I would imagine it would be direct steering as in a push bike but with scooters and motorbikes the preferred method seams to be a tie rod arrangement, I'm exploring some sort of direct method of steering for motorbikes to keep the whole thing as light as possible.
What if two rigid arms connected the two wheels and each wheel was on a linear guide, like a strut? Or two semi rigid arms that could bend like snowboards, and that would be the suspension?
what about having forward pivoting swing arms with shocks mounted to a pivoting arm that remains parallel with the ground? as the arms swing through their arcs, the variations will be in wheelbase instead of track. with limited wheel travel the variations in rake may be minimized by the length of the swing arms. for long travel suspension 4 arms may be required to keep rake more constant
captarmour - it may seem counter intuitive but if you model your idea, you'll find that at the road surface, there would indeed be a dramatic increase of track width with lean. All else being equal, the parallelogram maintains track width with lean.
Eerst moet je jezelf afvragen, waar wil ik rijden met mijn velomobiel? in een drukke stad, en op smalle fietspaden ? of op buitenwegen in bos en natuur, en in de bergen? in het laatste geval, hebben al deze ontwerpen weinig zin, maar ik vond het een zeer informatieve video, dank je
(Thanks to google translate!) Good comment, this sort of machine would be best suited to cities with good cycle lanes, other flattish cycle lanes and quieter rural roads. For hilly areas or off road, I’d take a different sort of bike!
When it comes to driving 2 rear wheels I think driving the rear axel with one-way clutches on either wheel would be a more elegant solution than a differential. Basically, all of the power would go into whichever wheel is moving slowest, and the vehicle would be self-righting (it would want to go straight) and it would never spin out unless BOTH wheels had no traction. Basically it would function opposite of a differential. The Quattrovelo has a system like this. I know you aren't intending on making a delta configuration, but I thought I might mention it since it was discussed in the video.
Just wondering, at about 1:09 in the video you mention that deployable landing gear is a strategy that can be used to stabilzie a two wheeled vehicle at low speeds. You mention later in the video that this strategy is not really ideal. Can you elaborate further on why deployable landing gear is not as good a solution as adding a third wheel and a tilting mechanism? It seems that the deployable landing gear system has been used successfully on faired two wheeled vehicles, such as Burt Munroe's faired motorcycle.
I guess there are pros and cons to both approaches, depending on what you are trying to achieve. The landing gear system seems to me to be slightly more complex and less elegant and may need to accommodate uneven ground.
I wonder whether keeping balance on a mechanism like this is as intuitive as on a bicycle or whether one has to re-learn. As I understand it, balancing on an eco-mobile, for example, is a bit counter-intuitive. Also, have you considered that at some point it doesn't make sense for the tires to lean any further, as they will loose traction, while it may make sense to still allow the rider to lean further in order to keep their center of gravity ahead of the bicycle to prevent tipping?
@@MetalMachineShop Nice. I've given this a lot of thought as well, so it was fun to accidentally stumble onto your video. There's a french quad bike with full suspension that looks really impressive that seems to use centrifugal force to do the leaning for you (by placing the pivot above the center of gravity), as opposed to the classic bicycle-style where you have to anticipate the centrifugal forces and get ahead of them. The dampers keep it upright and from swinging around too much. The mechanism takes up a ton of real estate though, so it's not aerodynamic at all (but plenty off-road capable). I've currently got ideas for a kneeling/tilting mechanism that's controllable separately from turning and doesn't require shifting one's body weight to control it, but likewise, I'll just have to test it to see if it's feasible.
This is brilliant seeing your thought process. I've also been playing around with this concept in my head. I do have a serious question though. Wouldn't the 2 front wheels tilt at different angles in a turn (actually all 3 would be at different tilt angles) due to the different paths each one is taking? The angles would be dependent on speed and radius of turn I think.
Would angling the wheels so that the contact point of the wheel with the ground is in-line with the arms help? Sort of like how some wheel chairs have tilted wheels to achieve better stability.
This is uncannily like a project I shelved a decade or so ago. Even the sketches and model are pretty much identical. Great minds..! Have you considered a delta layout with a Calleja type twin trailing swing arm setup. Calleja used a diff on his motorised test bed but with a narrow enough track you could possibly do without - or even drive a single rear wheel ( unless it would cause some unwanted yaw effects..?) Anyway it was fun to watch you talk through the same work, the same way.. Thanks for sharing.
Ha! I don’t claim any of my work is original - interesting to hear that other people have come to similar conclusions! I think the tadpole configuration has advantages in terms of mechanical simplicity but the deltas probably look better.
Incorporating torsion bars as the inner pivot shafts eliminates interference from shocks or springs as you depict them as well as maintains upright stance when stationary with a small amount of preload. Simple, lightweight and effective for a human powered vehicle.
@@flannel2699 That's why I suggested small torsion bars. Depending on the number of pivot points he uses, he could get away with just one or two. By coupling the suspension and tilting systems, the design is simplified. Fewer parts, less interference, less weight. Even damping could be incorporated using friction discs at select pivots instead of hydraulics. Human power vehicle performance is seriously degraded as weight increases. Less weight=less power required/better performance. It's easy to copy someone else's design/idea but designing and building your own working solution is much more satisfying.
Steven Mitchell - I thought you were suggesting using torsion bars as actual pivots (like a 50's Riley or E-Type) but if you mean torsion bars mounted coaxially within the pivots that would definitely be neat and compact. Apologies if I misunderstood. Many seasoned engineers have made similar mistakes regarding tilting vehicle linkage setups. Even the eminent Tony Foale got it completely wrong in his book on the subject.. ( so you would have been in pretty good company..!)
You should look at tilting mechanisms for motorcycle cars. I'm not sure if it would work with independent suspension but something like the Flxi Flyer might simplify things. I think once you start to look at how much turning the wheels starts to change and complicate load and geometry you might forget about some of your concerns.
Hi there, yes, my latest design has a top-mounted shock. I think this is the most convenient position for it now that I’ve thought about it a bit more!
My idea would be an arm goes from a wheel to the bike body's half plus (length a) the wheel axis length to the wheel's center (length b/2), total arm length of a left or right arm=a+b/2. The arms are mounted at a vertical plate on the bike body and have to be curved to not touch each other. That means, at the bike body, they are before and behind each other. The result should be two exact parallelograms. What do you think about it?
What a great video with so much detailed information, Just a thought, would you use any caster angle with these setups for a tadpole trike configuration.
Mike Bull hi, thanks for your comment. The video just shows the tilting geometry, the steering geometry will require a castor angle and king pin angle to prevent bump steer. I’ve been working on these aspects of the design and am hoping to upload another video one these aspects in due course
Hi. I enjoyed your video and approach! Tilting trikes have been on my mind for years. Would it help if the two vertical arms supporting each wheel were angled out at the bottom so they aim at the tyre contact patch? I've done that on a gravity racer and it really helped. Obviously the inboard suspension pivots would no longer be in line vertically if the top and bottom arms were to be of equal length. Kris
Hi, thanks for the comment. I agree that the steering pivots/kingpin should be angled as you describe in order to reduce/eliminate bump steer. I’m planning to upload another video of my emerging design that includes this feature, just as soon as I get time.
what a nice demonstration and explanation. did you consider to use a expansion shock instead of a compression shock? this way you could "invert" the shock and place it under the upper arms where you might have more room.
Interessante, mas poderia deslocar todo mecanismo para fora do centro da roda, levando para frente. Depois colocar braços, tipo facão, para suportar a suspensão das rodas. Já vi algo parecido e parece funcionar.
You mentioned that if the two wheels were in the rear (delta design) it would make things easier but the hassle involved in the drive train engineering wouldn't be worth it. Have you considered doing it in a delta design with front wheel drive, as Cruzbikes are designed?
Yes I thought about it but I don’t really like the front wheel drive concept. It would require some non-standard parts and put a lot of twist into the chain on steering, depending on the design. Also I’m not keen on delta trikes; anecdotally they have poor aerodynamics and with only one wheel in front you don’t get the advantage of improved grip at the front that a tadpole trike gives you. My latest video talks about my velomobile design if you are interested!
hi i dont know if this is a dead end but a old f1 car from cooper would use a leaf spring as the upper arms i would imagine a composite mono spring wouldn't create much drag out in the air and could save you space
I was thinking about using forwards facing swinging arms - pivoting at about the same place as my bum fore and aft - I must get my scissors and cardboard out.
If you place the joints from the lower arms more to each side, the inner wheel will tilt more while the outer wheel tilts less. And if you add the steering you must have a straight line between the wheel ground contact point, the outer joint of the lower arm and the outer joint of the upper arm. With this turning axis you can steer easily without having the wheels to move or rub on the ground when steering. (I hope this made sense as I‘m no native speaker)
I was actually thinking about a similar velomobile design, but for mine the body would be slightly higher and flatter on the bottom, and the fairing would be T shaped looking roulghly like cannards but capable of flexing. I was wanting to do a jet plane canopy like teardrop shaped glass dome on the top as well. I would love to work with you on the design and implementation.
I'm just thinking Ackerman should be applied to your tilting action, as that is how you'll be steering at higher speeds. I assume higher speed correct tracking is more important to you than low speed start and end of ride tracking. The turning mechanism is only needed for slow speed small radius maneuvering. Maybe the tilting mechanism can be a sub-assembly mounted on a pivot, which would be the pitch axis for turning the whole tilting assemble in the left/right horizontal plane for tight turns.I'm Thinking of a handle bar that can be pushed left and right for tilt, and twisted in the usual bicycle manner for turning the tilt mechanism on the horizontal plane for tight turns. I'm saying this several different ways, because I can't put a picture of it on TH-cam.
Been playing around with trike design and really want to build one with a leanable back end. Have you considered what each scenario would do if you changed you perspective angle a bit? Would any of those situations improve by leaving the top bar in position but kick out the bottom bar more to the rear? It seems to me the bars needs to remain parallel but not necessarily directly up and down from each other. To help visualize imagine top bar leaned forward like a wheel/chain stay towards the top of the seat post
I'm not sure but it seems that body clearance should increase as the tilt angle increases for vertical state stabilization. But not much, probably it causes risk of overturn at speed. Thank you for shared analysis.
Some insight from having built a bunch of human powered streamliners including 3 wheeled leaners. Weight and complexity are always a hindrance to efficiency when powered by fractional horsepower engines (humans). Lighter, simpler yields the best results. A 2 wheeler with side openings so either a foot or hand can touch the ground at a stop worked out the best ... for me. The speeds that can be attained with a good light weight human powered streamliner it truly amazing. Your results may vary.
Hi, thanks for your comment! I totally agree that light weight and simplicity is the right way to go for out and out speed. I am prepared to sacrifice a bit (but not too much) of speed for practicality. I am pitching my design at reasonably practical year round (in UK) commuting type use, and and intending to use electrical assistance. I also have in mind a faster two-wheeled design. Anyway, it’s all still on the drawing board at this point!
Lightweight and simplicity is a nice advantage for all weather, everyday practicality. Even when adding the weight of motors and batteries. This statement is based on years of complex testing and personal experience. All the best with your build. Your results may vary.
So two wheels are better than 3 except at very low speeds and temporary stopping. Presumably that is a relatively small proportion of the time that you are in the vehicle. Folding outriggers seem a lot simpler mechanically than creating a hugely elaborate steering mechanism. Even a motorised flywheel that uses precession to resist falling seems easier than the steering complexity.
You're absolutely right, three wheels have few advantages over two, other than potentially less chance of losing grip and low-siding during cornering. It does make for an interesting design challenge (in my mind at least).
Been thinking of a motorcycle along these lines and having same issues finding a decent suspension setup without drawbacks whilst ensuring suspension and tilting work in harmony
Found your video very interesting and informative. Really like your method of paper and pin analysis. Wonder if you experimented with unequal length parallel arms and/or a mono-shock for the upper. Also, a more bulbous front may not be so terrible for aerodynamics. It would be the classical teardrop shape, although not as appealing to the eye. As with all things mechanical, there is no one perfect solution. It's always a compromise. Keep going and the best of luck.
Hi, I think you are right that a more bulbous design would not harm aerodynamics (and would probably be better) but it would reduce wheel clearance and would look a bit pants too!
Forgive me if you've said, but did you consider Akerman angles in your chosen design? The inside tire in a turn will need to have more lean than the outer, to follow different radii.
AngelAndTheWolf Hi, I am intending to use Ackerman geometry in the steering geometry. I didn’t cover this in the video, which was just about the tilting mech. I am planning another video soon when time permits, which will look at the steering geometry, including caster angle and kingpin angle in more detail.
This comment is very late. At the core, you are essentially trying to develop a tilting double wishbone suspension. As you have discovered, that type of suspension can be complicated. Have you considered developing a trailing arm suspension? You can use torsion bars or polyurethane pads for suspension which requires little room and the independent nature of the trailing arms naturally lays itself to correct angles when tilting. I'm curious what you ended up with. I'll go looking for more of your videos to see your final build. Thank you for sharing.
I've been interested in leaning suspension for years, and I've seen various different setups for the leaning mechanism but I've never seen anyone explain their design choices or even talk about the geometry. Personally, I'm more interested in motor vehicles, whether it's bikes or single seat cars, trikes of either configuration or quads. I do have one question that I have yet to see answered, is there an Ackermann equivalent for lean angles, or do you actually want the two wheels to be as parallel as possible? In my mind, though I don't have much of an argument to back up why I think this, it makes sense that there should be some form of vertical Ackermann for leaning, for the same reason normal steering has Ackermann angles; the wheel with the tighter turn radius turns, or in this case leans, more than the wheel with the broader turn radius. If it helps with my question at all, I'm also talking about wider tires with an offset wheel, to get all the pivots as close to the wheel's centerline; similarly to how a dished wheel or above-wheel design would work better on a trike like this.
Hi, I’m glad you asked this question because I have been thinking about this myself. I am sure that the Ackerman principle applies to tilting designs as it does to upright vehicles, since the inner wheel is following a tighter radius just the same. I’ve researched this and found at least one reference confirming this (I think it was the Yamaha motortrike that uses Ackerman steering). The challenge then is to arrange the steering geometry to give consistent Ackerman steering throughout the lean angle range. I am planning to upload a video on this fairly soon.
@@MetalMachineShop Metal Machine Shop Thanks for the reply. I hadn't considered Ackerman at various angles of lean. It makes sense, though, as Ackerman in the steering would improve performance. My original question was more about different lean angles of the wheels. Should the wheel with the tightest turning radius lean more than the wheel with the broadest turn radius? This would also apply to body lean and third wheel lean on a trike. Or is equivalent lean angles more optimal?
Yes I suppose in theory the inner wheel with tighter turn radius should lean more than the outer wheel but I’m not convinced it’s worth worrying about for practical purposes. I haven’t analysed this in detail but it would seem that the difference in lean between the inner and outer wheel should be more for a tighter-radius turn, but a slow speed tight radius turn may have a smaller lean angle than a high speed, large-radius turn. The larger the turn radius, the smaller the difference in inner-to-outer wheel lean. The lack of a liner relationship between speed, turn radius and lean angle leads me to think there is no design sweet-spot for difference in inner-to-outer wheel lean angle. Commercial trike scooters and motorcycles don’t appear to incorporate this or suffer from it. Just my view!
@@MetalMachineShop TLDR: Suspension geometry causes issues, especially at the potential differential lean angles that could be used here. As ideal suspension is based on a parallelogram, but ideal differential lean angles are based on a trapezoid. An active form of manipulating lean angles could be possible, but the suspension geometry issue remains, but there is a solution where suspension could actuate the lean angle actuator to compensate for suspension geometry when the suspension is actuated, but this is a very complex issue that may not even be feasible without proper research and development. There's potential in the future, but until then, leaning suspension will remain rigid parallelograms with parallel leaning. Differential leaning may not even have a benefit at the end of the day. I've come to the realization that differential leaning is too complicated and/or too difficult, due to suspension travel. To achieve differential lean angles, just like differential stereing angles in Ackermann steering, you need a trapezoidal frame consisting of the center body, control arms, and wheel hub/knuckle. Problem is, once you introduce a non-parallelogram into that geometry, the extent of travel can produce odd angles, especially when you look at how large of a difference in lean angles might be required. The solution to this? Active angle change, essentially a steering rack for the upper control arm. This would introduce a ratio between lean and steering. But the problem of suspension geometry remains. The solution to that? A system that is actuated by the driver but also actuated by the suspension. Basically if you hit a significant bump or hole, the suspension can 'fix' the geometry of the control arms to retain proper wheel angle, and not throw that wheel out of control. This is where the 'too complicated and/or too difficult' part comes in. You need an actuator that is actuated by driver input and suspension input, but this actuator can not inversely actuate either input itself, and either input cannot actuate each other with this actuator as a middle-man in the design. Simplest design would be a hydraulic system, but this would require complicated valve logic to make it work, if that valve logic is even capable of existing. More complex design would be to use electronics and an ECU to assist in this kind of design, but again, can the logic theoretically exist in a way that makes the system usable. The electronic design could work in the sense that suspension actuation takes priority over driver input for lean acuation, but then the problem becomes how fast can this work. Speed would be a problem the hydraulics could fix, but then it's an issue of getting that logic to work with a complex valve setup. Maybe a hybrid could work, where it's ECU controlled valves, but again, will the electronics be fast enough to do this. It's a constant back and forth of how would it work and could it work, and it's not an easy situation to solve without an engineering background, money to research and develop this, and having the proper tools to research this. Then the question becomes about reliability of the mechanism. All things given, I can see why every design uses a parallelogram, or a shape as close to a parallelogram as they can get. A solid axle variant could make this possible, but then you'd be getting into an entirely different form of suspension, which may not even work itself. This issue seems more like it would be someone's Master's or Ph.D. thesis, or a project meant for a halo vehicle, where the mechanism may not even appear in other vehicles at all. It's an interesting concept, but just not feasible at this time, not until someone researches and develops a mechanism that not only works properly, but is also extremely reliable. It's still something I want to see researched, but I don't think we will see it researched any time soon, not until leaning trikes and quads become more popular on the consumer market as performance vehicles. It's more likely that a race team would develop something like this, assuming leaning trikes and quads ever become popular in big name racing, such as Formula. Even if we ever do see this researched and developed, we'll never see internal documentation, and the most we'll see is patents until someone can somehow reverse engineer the mechanisms. Sadly the most I can do, and the most anyone interested in this can do, is make it a theoretical concept that might work on paper, and maybe construct a physical version that wouldn't be up to the standard of production parts. For now, I just hope we'll see something like this in the future, but until then, leaning suspension will be rigid parallelograms. Who knows, differential leaning may not even have benefits, which is why we have yet to see anyone research it, as it may be too complex to result in benefits, where anything past simplicity results in diminishing returns.
@@MetalMachineShop Yeah I thought about this too. But it's really hard to Have an Ackerman steering as well as Ackerman leaning. Keeping wheels parallel is the best option and using lean wheels (road bike wheels) might reduce scrub I guess.
Yes, I was thinking that too. It would also avoid the need for the arms to be jointed in the middle so would be simpler. Need to dig out my beam-theory notes!🤓
Andrea Hailes According to my research on the subject, a car’s steering geometry would typically be arranged so that the king pin axis at the point it meets the ground is slightly inboard of the centre of the tyre’s contact patch (sometimes it’s outboard). This apparently avoids the instability that would occur if the two were coincident. The tyre will scrub against the ground when the wheels steer but this is unavoidable. I will use Ackerman steering geometry. A small amount of scrub is probably unavoidable and negligible. Hopefully.
Your a champion to share all these principles, all in all your card cut out concept is the best, one actually gets it
Thanks, I'm pleased you liked it!
Thank you for sharing this information. I have been trying to make a working Velomobile design. It's very hard to find people willing to share their concepts.
Try to find a blueprint for the original tilting sidecar on 20s-30' s Harley- Davidson rigs. I can't recall any more if that was a Harley or tilt- car patent. But talk to your local librarian, that's what they do... Find obscure source's of data in places you and I will never think of. Good luck + I'll catch you later.
Have you seen the F300 Life-Jet German prototype from the late '90's? Worth a look 😅
Really informative for a person who wants to build a tilting recumbent. You’ve given me a far greater understanding towards this endeavour👍
Please keep making videos sir. This was very educational for my own project.
Hi, I'm doing a similar exercise so thanks for posting this. What I am looking into is different tilt on the wheels, less on the outside of the turn and more on the inside, making the imaginary lines through the wheel axles meet in the centre of the turn.
For ages I been "planning" to make a EV trike 1+1 in tandem with motorcycle parts, but, since i didnt have the time space or money im seriulsy thinkin a electrically assisted trike bike to start with, this exercise was really very informative. thanks
Go for it!
@14:15. Could the straight vertical strut that the wheel mounts to be dished inwards? That might be easier than dishing the wheel? And if you placed the vertical strut behind the axle connection then you can add in some castor and potentially tuck the wheel in even further. Looking at my GoKart chassis as an example the offset and castor are adjustable according to the grip required on the day.
Yes I think that would all be possible. The important thing is the relative location of the pivots and the steering geometry. Once this is all decided, the parts themselves can be designed accordingly.
Very interesting. I was looking at how to make an IRS trick tilt and this gave me food for thought
This is a beautiful video. The communication works perfectly.
Superb and systematic approach to arrive various solutions for tilting wheels
Very interesting.... I will be back again for more inspiration on my project! Bravo!
Have you considered pushing the ideal geometry mechanism to the front or back of the wheel instead of on top? The horizontal bars would require quite some torsional rigidity but it would help with keeping it out of sight of the rider, keeping the body mounting points low and keeping the wheel size unconstrained.
I haven’t put much thought into that option, but would certainly be worth considering! Simplicity and minimising weight would be a good test of success.
An excellent video. Thank you for sharing your knowledge
Thank you for all your efforts, I have been thinking of building an electric trike and have been stumped for a long time on this issue.
This is really informative! One question though, how to make the vehicle stand upright on stop without any support?
Thanks - the normal way to do this is a tilt lock consisting of a modified brake disc and caliper.
Very interesting! Tilting seems to be the future of trike design!
It is, but even pros don't have the solution... maybe sk18 whatever with his wierd ass channel name and sick af asl.
I found this video to very interesting as I'm considering building my own velomobile
Fourteen minutes very well spent, been considering this and the problems that arise for some time now, out of interest how big a problem is tyre scrub and if you mounted the lower arm where it met the tyre slightly higher and angled the wheej outwards, (positive camber), would that be of benefit,
it might help, you’d have to make a model of some sort to prove it!
Muchas gracias por todas sus explicaciones. Me encanta este diseño, pero en suramérica son muy poco empleados y las rutas para bicicletas no son muy seguras.
Pretty cool. When ever I’m designing new machines. I always do cardboard and push pins. Works a treat and makes for real easy adjustments. Can’t wait to see what you build.
@Metal Machine Shop This appears to be the most comprehensive coverage on the subject on this platform. Congrats for that. No doubt many hope that this project comes to fruition and viewers get more information helpful to constructing the proposed vehicle. It is very curious that little is now heard of the much praised "Velotilt" trike with two rear wheels, first heard of about 2012. It looked so promising, while it's apparent absence from the market place suggests that it is still overcoming problems. Any light you could shed on this matter would be much appreciated. I look forward keenly to follow ups on this project. I am surprised that the topic of a leaning velo is not far more popular.
Thanks for the comment! I'm not sure what happenend to the Velotilt, I haven't found any up-to-date news on the internet. Nice looking machine though. It uses a different sort of tilting mechanism that I didn't cover in my video.
@@MetalMachineShop Remain keen to know if this velomobile is being built and hope you will advise along the way. Thanks for the velomobile upload.
I'm still working on the design so I'm not sure whether I will ever build it. Once the design is finished maybe I will share it with the velomobile community to see whether it's good enough to build! I'll try to upload another video in due course.
This is by far the most details built of the Tilting Trike ! I know im like 2 years late to this video but instant sub and love your build series
Fantastic piece of analysis! I've done most of this thinking before but without the pretty cardboard aided design. I don't have an aversion to FWD, so the image you showed of the tilting delta trike was right up my street.
I am moving from cardboard to computer aided design for the next phase!
The velotilt project was for sale not too long ago. It has plugs and molds for the body and some design work
Awesome! Question. If you can engineer some body lift into it. Wouldn’t it more likely stay upright at slow speeds?
in theory it might!
very interesting, perhaps you could use the buddy it self (a shell like) to transfer horizontal forces across. Could not see very clear the relationship to the driver's geometry.
This was very helpful. I did find success with slight separation with of the arms from the center point and using the t model but the t shape is just about 1/3rd the height of the space between the upper and lower arms. The points where the shocks connect to the t is the same as the inner pivot points of the arm. Then using the distance for the shock to measure out where it would attach to the lower arm. For body wise you may have to make a slight deviation in the body to allow room for the shocks which aerodynamically shouldn’t effect it to much. You can also prevent a lot of aerodynamic loss by using fine bristles on the slits which will allow it to essentially close the slit.
Best way to create prototypes in smale scale is Lego technik!!!!! Thx for the great video.
Ha! I actually did that. Ran out of bits though!
My experience is the same. 3D CAD takes the design to a next level.
From my purely digital work I learned that a powered or at least partially powered vehicle is necessary to achieve gains from the heavy tilting mechanism.
About the suspension and sideways tire-scrub; hossack suspension would solve this issue wouldn't it?
The complexity and mass would increase though
This is a very interesting video with a range of possible designs. The only thing I would say is you are having the single wheel on the same plane as the other two. As the single wheel is at least three/ four feet behind or in front of the other two the amount of scrub or lift can be ignored due to this change in the plane!
Do the two front wheels have to be beside the front of the body? If you moved them forward of the nose, they could be closer, and stay within the frontal area of the body. They could be two feet apart, providing stand-still stability, and faired individually for aerodynamic flow onto the nose. In addition, the nose would not restrict the vertical turning of the two wheels. You could employ a tilt mechanism to your handle bars, along with a standard rotating system for tighter corners. With the wheels close together, you could suspend them with a central shock.
Hi, they don’t have to be beside the body. In moving them forwards you would be trading length overall for reduced width but you are right, the steering wheels could be closer together which would be good. You would need to allow clearance for the frame/chassis.
Very interesting. Have you thought about running the tilt mechanism on the rear and using FWD? This would ease packaging and obviate the need for a differential.
Definitely an option but I think tadpole configuration is easier to make with greater use of standard bike components.
beautiful explaination and amazing idea of testing different ideas. this is how i would do it.
me gusto mucho la excelente explicación y los diferentes modelos y problemas que presentan, han sido de una gran ayuda para mi, quería sugerir en cuanto a la suspensión, porque no colocas un pequeño sistema de suspensión en cada rueda, igual que la que usas en la central y que cada rueda suspenda por individual, te voy a enviar un modelo de suspensión sencillo que usa una trike bike, buscare el link del vídeo y te lo comparto en otro msj
Man this video is fantastic!! I'm working on something similar and this is a gold mine!
That was excellent, Bravo!!! I build gravity racing vehicles and I have always thought a tilting suspension would be amazing, thank you for sharing such a vast amount of time and work!
The minds and technology of Lithuanian engineering are rough diamonds.
really like your evaluation, trail and error. where the center joints come together , please consider sliders that cross before connecting to shocks? thanks
Would it be possible to have a design with the front wheels at a slight angle instead of them being orthogonal to the ground?
At 5:18 you mention that one of the problems is that the lower pivot points of the parallellogram are offset relative to the contact point of the tires on the ground, creating a triangle that lowers the outer pivot and raising the inner pivot. If the wheels were angled inward at the bottom, it should be possible (geometrically) to lessen or completely eliminate this triangle.
Disclamer: I'm not an engineer and neither did I play around with pivoting models, so I suppose there are very likely some indesirable consequences that I forgot about. Indesirable consequences I can think of myself is that the angle will cause the velomobile to broaden at the top of the wheels and the velomobile riding continuously on the side of the tires and/or wheels, which they were not designed for.
Yes I guess you could do that but adding camber to the wheels could add a slight sideways force to the tyre rather than keeping the weight directly down through the centre of the wheel and tyre.
Thank you so much for this talk through of so many aspects that come to play in a suspension design like this. Much appreciated!
Thank you!
what are your thoughts on using driveshaft instead of chain? like the focus on efficient performance. solid work. good luck. if i sacrificed any efficiency it would be to (pun alert) lean toward larger wheels for smoother ride.
It can be done. I’ve seen a hire bike with a drive shaft. You would need hub gearing rather than normal bike gears. On my recumbent velomobile design, you would need a couple of universal joints to route the shaft around the rider, plus extra supporting bearings. Shaft drive would be a bit less efficient than chain, but could be enclosed more easily. I also found on my velomobile design that smaller wheels were needed to give steering clearance and to keep the overall length within reasonable limits. I talk about this in one of my other videos. Enjoyed the pun lol!
Very interesting, I’d love to see follow up vids on this project.
More planned...!
Excellent.
Hi, you would also consider to follow up our tilting trike ASCENDU, we have a youtube channel, th-cam.com/channels/u869xo02p4utwZpVxmCCaw.html
Few people today recall that the first Harley- Davidson side hacks we re of a tilting design. H- D didn't make them, that was a contract with a private co. During WW 11, the company made bus replacement parts. Afterwards that company was still in business, Nowadays they make the tilting platform buses in Los Angeles California.
Interesting video with a lot of thought in it. However, I suspect the problem is even more complex than it appears in this video. I think the problem also needs to be considered 3 dimensionally, and not just 2 dimensionally as presented here. Notice in particular the camber angles of the wheels relative to each other while in a lean as would be experienced in a turn. Each wheel is in a slightly different turn radius and should require a different camber than the other wheel. The inside wheel in a turn should have less camber than the outside wheel.
I think you are right. I'm working on a 3D CAD model at the moment which should help flush out some issues.
Does camber directly relate to local turning radius? Or are you recommending a camber angle/ turning radius relationship for wear characteristics or handling?
I like your very detailed analysis, but I am still confused by what controls the tilt to happen.
Is tilt controlled by the rider's balance or is tilt controlled by the steering mechanism.
I would imagine if tilt was a summed result of (steering and speed) or (centripetal force) then tilt stability would be constant of (center of gravity).
Could a pendulum pivoting on a disk (where the disk acts like the horn of a servo) and push rods from that disk control the tilt help? (The rider could be the weight of the pendulum)
What about housing the wheels in a shroud like airplane landing gear?
That way, you can have a pivot point in the center of the wheel..
Maybe something as simple as a bike fork that is horizontal instead of vertical,
sort of like a gimbal in a gyroscope. (Where tilt and steer are the 2nd and 3rd axises)
I think there is a gimbal in the rotor of a helicopter blades.. That is kind of what I am imagining.
I forgot to add..(I'm not sure if this was what you were talking about.) The turn radius of the wheels for inside and outside of the turning curve are different.
The inside curve wheel turns to a sharper angle.
Hi, the theory is that the tilting is completely passive. The trike balances in the same way as a bike, the mechanism described just allows the tilting to happen, only on three wheels not two.
@@WagonLoads Yes - I did another video on the steering geometry - video 3 in my tilting trike series. Vid 4 touches on it too if memory serves.
My thoughts were how to make it so that the center of gravity is controlled by the centripetal force of the turn, so that the bike auto-tilts to the right angle for the speed and turn radius you are doing. Thus making the bike self balancing.
Excelente trabajo. Estoy definiendo como hacer el basculante de mi futuro triciclo invertido. Gracias !!!
Amazing, I’d love To make a trike and this is so interesting, what happens if you have the passenger body volume tilt more than the wheels? Eg at 45deg the wheels are at 30 deg. Is that rideable? Really cool channel and presentation, subbed thanks!
I’m not sure what would happen but I tried to keep everything in line to keep it as close to a bike as possible.
Thank you MMC, very very interesting, you saved me a lot of work. One mechanism you didn't try was two pivot points in the center on the lower arms and one on the top, the same they use on the Quadro, do post another video if you try this geometry please. Thanks again for going to all this trouble.
Thanks! I think the Quadro design as you describe it would make the wheels angle outwards slightly relative to each other as the machine tilts or suspension compresses. The effect would be greater the further apart the bottom pivots are. I’m not sure what the advantage of this would be, but the Quadro seems to work pretty well!
MMS, I solved the above problem I discussed in my previous post (Quadro) simply by using your number 4b and turning it upside down, it would have the same result, I'm just wondering how Quadro solved this or didn't they ???? Correct me if I'm wrong but to have the correct geometry the top and bottom pivot points would have to have be aligned in the center such as in
figure 2a.
Do let us know how you solved the steering, for your project. I would imagine it would be direct steering as in a push bike but with scooters and motorbikes the preferred method seams to be a tie rod arrangement, I'm exploring some sort of direct method of steering for motorbikes to keep the whole thing as light as possible.
What if two rigid arms connected the two wheels and each wheel was on a linear guide, like a strut? Or two semi rigid arms that could bend like snowboards, and that would be the suspension?
This might both be suitable options depending on what you are trying to achieve. Worth experimenting!
what about having forward pivoting swing arms with shocks mounted to a pivoting arm that remains parallel with the ground? as the arms swing through their arcs, the variations will be in wheelbase instead of track. with limited wheel travel the variations in rake may be minimized by the length of the swing arms. for long travel suspension 4 arms may be required to keep rake more constant
captarmour - it may seem counter intuitive but if you model your idea, you'll find that at the road surface, there would indeed be a dramatic increase of track width with lean. All else being equal, the parallelogram maintains track width with lean.
@@flannel2699 oh yes you are so right! I was more concerned about scrub than track. I'll need to wrap my head around that.
captarmour - don't worry, it caught me out as well :)
How about hubless wheels? And since I see others thought of it, also in hub suspension.
Nicely done and the cut out graphic made it crystal clear. Cheers.
Eerst moet je jezelf afvragen, waar wil ik rijden met mijn velomobiel? in een drukke stad, en op smalle fietspaden ? of op buitenwegen in bos en natuur, en in de bergen? in het laatste geval, hebben al deze ontwerpen weinig zin, maar ik vond het een zeer informatieve video, dank je
(Thanks to google translate!) Good comment, this sort of machine would be best suited to cities with good cycle lanes, other flattish cycle lanes and quieter rural roads. For hilly areas or off road, I’d take a different sort of bike!
Can you try to lean the body while keeping the camber of the wheels steady?
I suppose it is possible but I’m not sure it would be a very satisfactory solution.
Great Presentation, I’m working on an idea for a tilting trike recumbent myself. Challenging I must say, your approach is inspiring!
Thanks! I hope your project is successful.
When it comes to driving 2 rear wheels I think driving the rear axel with one-way clutches on either wheel would be a more elegant solution than a differential. Basically, all of the power would go into whichever wheel is moving slowest, and the vehicle would be self-righting (it would want to go straight) and it would never spin out unless BOTH wheels had no traction. Basically it would function opposite of a differential. The Quattrovelo has a system like this.
I know you aren't intending on making a delta configuration, but I thought I might mention it since it was discussed in the video.
A tricky bit with the spring. Perhaps a torsion bar. Like an old pickuptruck.
Just wondering, at about 1:09 in the video you mention that deployable landing gear is a strategy that can be used to stabilzie a two wheeled vehicle at low speeds. You mention later in the video that this strategy is not really ideal. Can you elaborate further on why deployable landing gear is not as good a solution as adding a third wheel and a tilting mechanism? It seems that the deployable landing gear system has been used successfully on faired two wheeled vehicles, such as Burt Munroe's faired motorcycle.
I guess there are pros and cons to both approaches, depending on what you are trying to achieve. The landing gear system seems to me to be slightly more complex and less elegant and may need to accommodate uneven ground.
Do you know of any resources that discuss the advantages and disadvantages of both approaches?
@@MetalMachineShop
That was excellent, Bravo!!! I
Is the ATV front end suitable for tilting reverse trike conversion?
Hello good morning, excellent work do you think you can sell me the plans to build this piece.? Thank you very much.
I wonder whether keeping balance on a mechanism like this is as intuitive as on a bicycle or whether one has to re-learn. As I understand it, balancing on an eco-mobile, for example, is a bit counter-intuitive. Also, have you considered that at some point it doesn't make sense for the tires to lean any further, as they will loose traction, while it may make sense to still allow the rider to lean further in order to keep their center of gravity ahead of the bicycle to prevent tipping?
I'm thinking of building a simple prototype to test the usability of the basic design.
@@MetalMachineShop Nice. I've given this a lot of thought as well, so it was fun to accidentally stumble onto your video. There's a french quad bike with full suspension that looks really impressive that seems to use centrifugal force to do the leaning for you (by placing the pivot above the center of gravity), as opposed to the classic bicycle-style where you have to anticipate the centrifugal forces and get ahead of them. The dampers keep it upright and from swinging around too much. The mechanism takes up a ton of real estate though, so it's not aerodynamic at all (but plenty off-road capable). I've currently got ideas for a kneeling/tilting mechanism that's controllable separately from turning and doesn't require shifting one's body weight to control it, but likewise, I'll just have to test it to see if it's feasible.
Best Explanation video on TH-cam!!
Thanks!
This is brilliant seeing your thought process. I've also been playing around with this concept in my head. I do have a serious question though. Wouldn't the 2 front wheels tilt at different angles in a turn (actually all 3 would be at different tilt angles) due to the different paths each one is taking? The angles would be dependent on speed and radius of turn I think.
In theory maybe the tilt angles should be different, but I doubt it would have much impact in practice, especially with thin tyres.
Hi. Love your project
Just a suggestion use shock absorber on top instead of use in bottom..
Yes I think you are right about that
Thank you for the educational video. Much appreciated!
hafeexius Thanks, glad you found it interesting!
Would angling the wheels so that the contact point of the wheel with the ground is in-line with the arms help?
Sort of like how some wheel chairs have tilted wheels to achieve better stability.
This is uncannily like a project I shelved a decade or so ago. Even the sketches and model are pretty much identical. Great minds..!
Have you considered a delta layout with a Calleja type twin trailing swing arm setup. Calleja used a diff on his motorised test bed but with a narrow enough track you could possibly do without - or even drive a single rear wheel ( unless it would cause some unwanted yaw effects..?)
Anyway it was fun to watch you talk through the same work, the same way.. Thanks for sharing.
Ha! I don’t claim any of my work is original - interesting to hear that other people have come to similar conclusions! I think the tadpole configuration has advantages in terms of mechanical simplicity but the deltas probably look better.
Incorporating torsion bars as the inner pivot shafts eliminates interference from shocks or springs as you depict them as well as maintains upright stance when stationary with a small amount of preload. Simple, lightweight and effective for a human powered vehicle.
Steven Mitchell - he's designing a free leaning trike. The suspension and tilting are decoupled.
@@flannel2699 That's why I suggested small torsion bars. Depending on the number of pivot points he uses, he could get away with just one or two. By coupling the suspension and tilting systems, the design is simplified. Fewer parts, less interference, less weight. Even damping could be incorporated using friction discs at select pivots instead of hydraulics. Human power vehicle performance is seriously degraded as weight increases. Less weight=less power required/better performance. It's easy to copy someone else's design/idea but designing and building your own working solution is much more satisfying.
Steven Mitchell - I thought you were suggesting using torsion bars as actual pivots (like a 50's Riley or E-Type) but if you mean torsion bars mounted coaxially within the pivots that would definitely be neat and compact. Apologies if I misunderstood. Many seasoned engineers have made similar mistakes regarding tilting vehicle linkage setups. Even the eminent Tony Foale got it completely wrong in his book on the subject.. ( so you would have been in pretty good company..!)
nice information sir. thankyou so much. its can help me to finish my final project. please keep this video sir :)
Greate job.
What will work to get the bicycle self supported?
It should balance in the same way as a normal bike or like a reverse-trike scooter.
You should look at tilting mechanisms for motorcycle cars. I'm not sure if it would work with independent suspension but something like the Flxi Flyer might simplify things. I think once you start to look at how much turning the wheels starts to change and complicate load and geometry you might forget about some of your concerns.
Is there any possibility in your velomobile design to implement shock above upper arms? There would be no clearance issues then...
Hi there, yes, my latest design has a top-mounted shock. I think this is the most convenient position for it now that I’ve thought about it a bit more!
My idea would be an arm goes from a wheel to the bike body's half plus (length a) the wheel axis length to the wheel's center (length b/2), total arm length of a left or right arm=a+b/2. The arms are mounted at a vertical plate on the bike body and have to be curved to not touch each other. That means, at the bike body, they are before and behind each other. The result should be two exact parallelograms. What do you think about it?
Hi, sounds like a good theory. Should work; you could test it by building a CAD model.
Cheers, MMS.
What a great video with so much detailed information, Just a thought, would you use any caster angle with these setups for a tadpole trike configuration.
Mike Bull hi, thanks for your comment. The video just shows the tilting geometry, the steering geometry will require a castor angle and king pin angle to prevent bump steer. I’ve been working on these aspects of the design and am hoping to upload another video one these aspects in due course
이제까지본 강연중에 최고입니다.이해하는데 많은도움이되었네요. 만들떼 참고할게요
감사합니다
Hi. I enjoyed your video and approach! Tilting trikes have been on my mind for years. Would it help if the two vertical arms supporting each wheel were angled out at the bottom so they aim at the tyre contact patch? I've done that on a gravity racer and it really helped. Obviously the inboard suspension pivots would no longer be in line vertically if the top and bottom arms were to be of equal length. Kris
Hi, thanks for the comment. I agree that the steering pivots/kingpin should be angled as you describe in order to reduce/eliminate bump steer. I’m planning to upload another video of my emerging design that includes this feature, just as soon as I get time.
what a nice demonstration and explanation.
did you consider to use a expansion shock instead of a compression shock? this way you could "invert" the shock and place it under the upper arms where you might have more room.
Yes that would definitely be an option!
Interessante, mas poderia deslocar todo mecanismo para fora do centro da roda, levando para frente. Depois colocar braços, tipo facão, para suportar a suspensão das rodas. Já vi algo parecido e parece funcionar.
You mentioned that if the two wheels were in the rear (delta design) it would make things easier but the hassle involved in the drive train engineering wouldn't be worth it. Have you considered doing it in a delta design with front wheel drive, as Cruzbikes are designed?
Yes I thought about it but I don’t really like the front wheel drive concept. It would require some non-standard parts and put a lot of twist into the chain on steering, depending on the design. Also I’m not keen on delta trikes; anecdotally they have poor aerodynamics and with only one wheel in front you don’t get the advantage of improved grip at the front that a tadpole trike gives you. My latest video talks about my velomobile design if you are interested!
hi i dont know if this is a dead end but a old f1 car from cooper would use a leaf spring as the upper arms i would imagine a composite mono spring wouldn't create much drag out in the air and could save you space
I think a leaf spring would be a good solution provided it wasn’t too bendy.
Did you try turning that T arm up side down ? Hook both springs to the bottom of the T arm upside down.Your missing out on 18 to 23 degrees of travel.
Super interesting analysis, thank you for your work.
I was thinking about using forwards facing swinging arms - pivoting at about the same place as my bum fore and aft - I must get my scissors and cardboard out.
that should work as long as the tilting and steering geometry and preserved.
If you place the joints from the lower arms more to each side, the inner wheel will tilt more while the outer wheel tilts less.
And if you add the steering you must have a straight line between the wheel ground contact point, the outer joint of the lower arm and the outer joint of the upper arm. With this turning axis you can steer easily without having the wheels to move or rub on the ground when steering.
(I hope this made sense as I‘m no native speaker)
I was actually thinking about a similar velomobile design, but for mine the body would be slightly higher and flatter on the bottom, and the fairing would be T shaped looking roulghly like cannards but capable of flexing. I was wanting to do a jet plane canopy like teardrop shaped glass dome on the top as well. I would love to work with you on the design and implementation.
I'm just thinking Ackerman should be applied to your tilting action, as that is how you'll be steering at higher speeds. I assume higher speed correct tracking is more important to you than low speed start and end of ride tracking. The turning mechanism is only needed for slow speed small radius maneuvering. Maybe the tilting mechanism can be a sub-assembly mounted on a pivot, which would be the pitch axis for turning the whole tilting assemble in the left/right horizontal plane for tight turns.I'm Thinking of a handle bar that can be pushed left and right for tilt, and twisted in the usual bicycle manner for turning the tilt mechanism on the horizontal plane for tight turns. I'm saying this several different ways, because I can't put a picture of it on TH-cam.
Been playing around with trike design and really want to build one with a leanable back end.
Have you considered what each scenario would do if you changed you perspective angle a bit? Would any of those situations improve by leaving the top bar in position but kick out the bottom bar more to the rear? It seems to me the bars needs to remain parallel but not necessarily directly up and down from each other.
To help visualize imagine top bar leaned forward like a wheel/chain stay towards the top of the seat post
There is no reason for the top arms to be directly above the bottom ones, so there is room for experimentation.
I'm not sure but it seems that body clearance should increase as the tilt angle increases for vertical state stabilization. But not much, probably it causes risk of overturn at speed. Thank you for shared analysis.
Some insight from having built a bunch of human powered streamliners including 3 wheeled leaners.
Weight and complexity are always a hindrance to efficiency when powered by fractional horsepower engines (humans).
Lighter, simpler yields the best results.
A 2 wheeler with side openings so either a foot or hand can touch the ground at a stop worked out the best ... for me.
The speeds that can be attained with a good light weight human powered streamliner it truly amazing.
Your results may vary.
Hi, thanks for your comment! I totally agree that light weight and simplicity is the right way to go for out and out speed. I am prepared to sacrifice a bit (but not too much) of speed for practicality. I am pitching my design at reasonably practical year round (in UK) commuting type use, and and intending to use electrical assistance. I also have in mind a faster two-wheeled design. Anyway, it’s all still on the drawing board at this point!
Lightweight and simplicity is a nice advantage for all weather, everyday practicality. Even when adding the weight of motors and batteries. This statement is based on years of complex testing and personal experience.
All the best with your build.
Your results may vary.
So two wheels are better than 3 except at very low speeds and temporary stopping. Presumably that is a relatively small proportion of the time that you are in the vehicle. Folding outriggers seem a lot simpler mechanically than creating a hugely elaborate steering mechanism. Even a motorised flywheel that uses precession to resist falling seems easier than the steering complexity.
You're absolutely right, three wheels have few advantages over two, other than potentially less chance of losing grip and low-siding during cornering. It does make for an interesting design challenge (in my mind at least).
Been thinking of a motorcycle along these lines and having same issues finding a decent suspension setup without drawbacks whilst ensuring suspension and tilting work in harmony
Found your video very interesting and informative. Really like your method of paper and pin analysis. Wonder if you experimented with unequal length parallel arms and/or a mono-shock for the upper. Also, a more bulbous front may not be so terrible for aerodynamics. It would be the classical teardrop shape, although not as appealing to the eye. As with all things mechanical, there is no one perfect solution. It's always a compromise. Keep going and the best of luck.
Hi, I think you are right that a more bulbous design would not harm aerodynamics (and would probably be better) but it would reduce wheel clearance and would look a bit pants too!
Forgive me if you've said, but did you consider Akerman angles in your chosen design? The inside tire in a turn will need to have more lean than the outer, to follow different radii.
AngelAndTheWolf Hi, I am intending to use Ackerman geometry in the steering geometry. I didn’t cover this in the video, which was just about the tilting mech. I am planning another video soon when time permits, which will look at the steering geometry, including caster angle and kingpin angle in more detail.
This comment is very late. At the core, you are essentially trying to develop a tilting double wishbone suspension. As you have discovered, that type of suspension can be complicated. Have you considered developing a trailing arm suspension? You can use torsion bars or polyurethane pads for suspension which requires little room and the independent nature of the trailing arms naturally lays itself to correct angles when tilting. I'm curious what you ended up with. I'll go looking for more of your videos to see your final build. Thank you for sharing.
Hopefully you found the test ride video! Sorry for the late reply.
Can you explain how tilting works on a carver?
I still don't understand how it works
Great Explanation Technique...
I've been interested in leaning suspension for years, and I've seen various different setups for the leaning mechanism but I've never seen anyone explain their design choices or even talk about the geometry. Personally, I'm more interested in motor vehicles, whether it's bikes or single seat cars, trikes of either configuration or quads.
I do have one question that I have yet to see answered, is there an Ackermann equivalent for lean angles, or do you actually want the two wheels to be as parallel as possible? In my mind, though I don't have much of an argument to back up why I think this, it makes sense that there should be some form of vertical Ackermann for leaning, for the same reason normal steering has Ackermann angles; the wheel with the tighter turn radius turns, or in this case leans, more than the wheel with the broader turn radius. If it helps with my question at all, I'm also talking about wider tires with an offset wheel, to get all the pivots as close to the wheel's centerline; similarly to how a dished wheel or above-wheel design would work better on a trike like this.
Hi, I’m glad you asked this question because I have been thinking about this myself. I am sure that the Ackerman principle applies to tilting designs as it does to upright vehicles, since the inner wheel is following a tighter radius just the same. I’ve researched this and found at least one reference confirming this (I think it was the Yamaha motortrike that uses Ackerman steering). The challenge then is to arrange the steering geometry to give consistent Ackerman steering throughout the lean angle range. I am planning to upload a video on this fairly soon.
@@MetalMachineShop Metal Machine Shop Thanks for the reply. I hadn't considered Ackerman at various angles of lean. It makes sense, though, as Ackerman in the steering would improve performance.
My original question was more about different lean angles of the wheels. Should the wheel with the tightest turning radius lean more than the wheel with the broadest turn radius? This would also apply to body lean and third wheel lean on a trike. Or is equivalent lean angles more optimal?
Yes I suppose in theory the inner wheel with tighter turn radius should lean more than the outer wheel but I’m not convinced it’s worth worrying about for practical purposes. I haven’t analysed this in detail but it would seem that the difference in lean between the inner and outer wheel should be more for a tighter-radius turn, but a slow speed tight radius turn may have a smaller lean angle than a high speed, large-radius turn. The larger the turn radius, the smaller the difference in inner-to-outer wheel lean. The lack of a liner relationship between speed, turn radius and lean angle leads me to think there is no design sweet-spot for difference in inner-to-outer wheel lean angle. Commercial trike scooters and motorcycles don’t appear to incorporate this or suffer from it. Just my view!
@@MetalMachineShop TLDR: Suspension geometry causes issues, especially at the potential differential lean angles that could be used here. As ideal suspension is based on a parallelogram, but ideal differential lean angles are based on a trapezoid. An active form of manipulating lean angles could be possible, but the suspension geometry issue remains, but there is a solution where suspension could actuate the lean angle actuator to compensate for suspension geometry when the suspension is actuated, but this is a very complex issue that may not even be feasible without proper research and development. There's potential in the future, but until then, leaning suspension will remain rigid parallelograms with parallel leaning. Differential leaning may not even have a benefit at the end of the day.
I've come to the realization that differential leaning is too complicated and/or too difficult, due to suspension travel. To achieve differential lean angles, just like differential stereing angles in Ackermann steering, you need a trapezoidal frame consisting of the center body, control arms, and wheel hub/knuckle. Problem is, once you introduce a non-parallelogram into that geometry, the extent of travel can produce odd angles, especially when you look at how large of a difference in lean angles might be required.
The solution to this? Active angle change, essentially a steering rack for the upper control arm. This would introduce a ratio between lean and steering. But the problem of suspension geometry remains.
The solution to that? A system that is actuated by the driver but also actuated by the suspension. Basically if you hit a significant bump or hole, the suspension can 'fix' the geometry of the control arms to retain proper wheel angle, and not throw that wheel out of control.
This is where the 'too complicated and/or too difficult' part comes in. You need an actuator that is actuated by driver input and suspension input, but this actuator can not inversely actuate either input itself, and either input cannot actuate each other with this actuator as a middle-man in the design.
Simplest design would be a hydraulic system, but this would require complicated valve logic to make it work, if that valve logic is even capable of existing. More complex design would be to use electronics and an ECU to assist in this kind of design, but again, can the logic theoretically exist in a way that makes the system usable. The electronic design could work in the sense that suspension actuation takes priority over driver input for lean acuation, but then the problem becomes how fast can this work. Speed would be a problem the hydraulics could fix, but then it's an issue of getting that logic to work with a complex valve setup. Maybe a hybrid could work, where it's ECU controlled valves, but again, will the electronics be fast enough to do this. It's a constant back and forth of how would it work and could it work, and it's not an easy situation to solve without an engineering background, money to research and develop this, and having the proper tools to research this. Then the question becomes about reliability of the mechanism.
All things given, I can see why every design uses a parallelogram, or a shape as close to a parallelogram as they can get.
A solid axle variant could make this possible, but then you'd be getting into an entirely different form of suspension, which may not even work itself.
This issue seems more like it would be someone's Master's or Ph.D. thesis, or a project meant for a halo vehicle, where the mechanism may not even appear in other vehicles at all. It's an interesting concept, but just not feasible at this time, not until someone researches and develops a mechanism that not only works properly, but is also extremely reliable.
It's still something I want to see researched, but I don't think we will see it researched any time soon, not until leaning trikes and quads become more popular on the consumer market as performance vehicles. It's more likely that a race team would develop something like this, assuming leaning trikes and quads ever become popular in big name racing, such as Formula. Even if we ever do see this researched and developed, we'll never see internal documentation, and the most we'll see is patents until someone can somehow reverse engineer the mechanisms.
Sadly the most I can do, and the most anyone interested in this can do, is make it a theoretical concept that might work on paper, and maybe construct a physical version that wouldn't be up to the standard of production parts.
For now, I just hope we'll see something like this in the future, but until then, leaning suspension will be rigid parallelograms.
Who knows, differential leaning may not even have benefits, which is why we have yet to see anyone research it, as it may be too complex to result in benefits, where anything past simplicity results in diminishing returns.
@@MetalMachineShop Yeah I thought about this too. But it's really hard to Have an Ackerman steering as well as Ackerman leaning. Keeping wheels parallel is the best option and using lean wheels (road bike wheels) might reduce scrub I guess.
The arms/Beans supporting the wheels could be flexible to absorb shock and removing the need for the rubber pads?
Yes, I was thinking that too. It would also avoid the need for the arms to be jointed in the middle so would be simpler. Need to dig out my beam-theory notes!🤓
@@MetalMachineShop check this one: th-cam.com/video/UMCs72AZ5W8/w-d-xo.html
Sir, if we want tilting angle between 5 to 15 degree then what is the best solution
Nithin Varghese I think my design 4, or variants of it, would be the best basis for a solution.
Metal Machine Shop thank you sir
Your kingpin design seems to have the centre point inline of where the tyre meets the road; how do you plan on dealing with scrub in corners?
Andrea Hailes According to my research on the subject, a car’s steering geometry would typically be arranged so that the king pin axis at the point it meets the ground is slightly inboard of the centre of the tyre’s contact patch (sometimes it’s outboard). This apparently avoids the instability that would occur if the two were coincident. The tyre will scrub against the ground when the wheels steer but this is unavoidable. I will use Ackerman steering geometry. A small amount of scrub is probably unavoidable and negligible. Hopefully.