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🤣small block weighs more than the car itself.

Thank you, it's a bit slow going but I'm hoping to get back into things soonish. Just have a crack at something with the kiddos, and work up to a bigger project! Good luck!

Thanks Paul! Appreciate your kind words. Part 4 is still in progress, I'm hoping to get some free time to finish off the pictures and start the recording! Cheers, Phil

@@teamjuric that’s excellent news!! Thanks Phil!!

Is there anything else you were interested in getting some more insight into? The next vid is less specific on cyclekarts and more a general chassis theory. Or are you more interested in cyclekart specific things

@@teamjuric I’m really enjoying watching how you’re applying general chassis design and actual race car dynamics to cyclekart cars please keep doing your thing!! Your karts gonna be a beast for real!!

Thanks for the feedback, unfortunately my take on cyclekarts is typically frowned upon by the majority of that community. So I'm just off to the side doing my thing, if I had the money I'd actually want to build my hillclimb/autocross car but this is the best way I can have fun

Thanks chief, I'll keep that in mind for the next video I'm working on, hopefully you've enjoyed the main bits of content

@teamjuric I you didn't think I was being rude, but I wanted your content, which was great.your 16-inch wheels were, "Do you get yours from, and what's the cost

I got them off eBay, the ones most expert cyclekarters think are the worst ones. They were $75AUD each Yeh it's hard to tell on this, there are lots of experts and keyboard warriors who like to comment on here...

Thanks for the kind words. I have more videos being worked on at the moment, chassis and suspension structures. Was there any specific things you wanted to know more about?

​@@teamjuric Hi, and thanks for asking. Apologies but the technical term escapes me, but how does one select front and rear spring rates to prevent unwanted oscillations? I think it's also called porpoising? Also, how critical is it to calculate roll rate? Your content is awesome. I spent over a year as an unofficial member of a Formula SAE team at a local college a few years ago. I've read every race car chassis and suspension book I can find - Adams, Aird, Costin and Phipps, Terry and Baker, Van Valkenberg and the Carrol Smith books. I also have Milliken and Milliken but it's so dense! Your content is the most detailed - and more importantly - accessible explanation of critical content that I've found. I just started cutting metal on a build that I've been preparing for/working on for many years. The base is a completely stripped '81 Bertone X1/9 body shell. What I'm doing is, think what Ferrari did with the 308 to build the 288 GTO - building a tubular chassis within the body shell and installing an Alfa twin cam + WRX transaxle in a longitudinal layout, with suspension based on a modified NA Miata geometry, preserving the inboard suspension pickups and building longer control arms to extend the OEM track from 56 in to ~60 in F/R. Similar to what Bilinski did with the front end of Midlana. Currently designing a street-specific roll cage to be build by a local speed shop after a design review, then I will fit up and tack tubing for the front and rear subframes then back to the speed shop for design review and final welding.

Hello! That sounds like a fantastic project, lots of scope to do a whole lot of fun sub projects!! I do like the x1/9, it's such a beautiful car, there is something special about the wedge style and pop up head lights that just put a smile on my face! Combine that shape and some better dynamics and a twin cam and you're going to have an absolute beast!! Id never heard of the Midlana until today, that looks super fun. For your questions about dynamics 1. Porpoising related oscillations are due to sensitive underbody aerodynamic interaction with the ground, complicated and not relevant to any of us, that term is very specific to high downforce stiffly sprung racing cars. 2. However for unwanted oscillations the very short version is, your dampers/shock absorbers do the job of absorbing, transmitting and dissipating the majority of the oscillations. 3. Slightly longer version, you will always get oscillations, but unwanted is very subjective, a passenger car doesn't want to be so stiff that you shake the fillings out of your teeth, but then a race car doesn't want floaty type oscillations that is comfortable for ride as aero platform control is so critical. So the challenge is picking what kind of behaviour you want and starting from there, RCVD does go into detail on this with good guidance on the two methods (ride frequency or travel). 4. I'll be getting into a lot more detail of roll rates in my next video that I'm currently working on, but essentially it is important. The relative roll stiffness of each axle is pretty much the main tool used to adjust the over/under/neutral steer balance of the car.

Thanks mate, I found the CAD models off GrabCAD. I try to avoid having to draw off the shelf gear.I always google them first to see if a model exists and if not I psych myself up and spend hours making dodgy simplified CAD models in between lots of swearing and crying. Link to the torque converter cad I think I used. If you have any questions or need a sounding board ping me a message in Facebook or insta messenger. grabcad.com/library/torque-converter-comet-tav2-30-100-gtc-tc2-1004-40-41p-1-bore-1/files Cheers, Phil

Found the engine there but missed this. Nice! Thank you!

@@coultl6556 my pleasure

FStudent is such a good experience for engineers, it's a shame that a small number of students get to do it or an equivalent project during school. What team are you part of and what aspect of the car are you involved in? Cyclekart is a great hobby for those who miss it, it's not all about the race, it's about the process and journey. There isn't a lot of appreciation of how much work is involved in not physical construction but also getting the design right so you don't ruin the fun. I'm glad there are others like you who get that these videos are not about building a cyclekart that will $hit on everyone and ruin everything. For me I'm just sharing the process and rationale behind my choices, ala design event... Im still trying to get the chassis video done before Christmas but there is a lot to go...

Hi Gavin, I used CAD and excel for my own kinematics for cost reasons, but at Monash I used and the team still use Susprog3d, which is excellent. Robert Small who wrote the software is super helpful and has been supporting it for over 20 years, I think he is up to build 1500! There are others like OptimumKinematics which is great, but it's very expensive and does almost the same as Susprog3d... Depending on the use case, maybe start with the optimumK trial and see if you want to invest in it. What project are you working on?

​@@teamjuric Thanks for the reply! I am actually planning on doing a very similar build to yours. I am trying to make a cyclekart inspired miniaturized lotus super 7. I plan on using independent front suspension and a fixed rear axle driven by a 125cc atv motor with about 7.5hp with a three speed transmission. I am going to try a chain driven front engine setup given the offset seating in the lotus and the very rearward driver position. I am also going to use the same or a very similar wheel and hub setup as a cyclekart. For the general floorplan I will us a wheelbase/track of ~177.5 cm x 97.5 cm. The whole build has a lot of similarities to the bloody mary hillclimb car.

That sounds awesome! Id love to see your progress. Hit me up if you have any questions, you can send me a message on insta or Facebook if you are on those

Thank you, Ive got another video in the works

Glad you enjoyed it! I should have been more clear as it's not meant to be specifically about cyclekarts, it's just the project I'm building, the content is actually for wider consumption and can be applied to anything. I'm lucky enough to have been exposed to this and I take the knowledge for granted, hopefully this is accessible to anyone who is actually interested in learning

Me neither

Not at all, it's a good question actually. Ideally it should be, but it's easier to fabricate them horizontally because I'm rusty. Eventually I want to simplify it to a single shaft and a bushing as the bearings and UJs are heavy.

I'm glad you liked it. The next episodes are still a bit away, but hopefully something before the end of the year.

I am currently building a wood mock up of my kart project similar to yours, it is a bit of a challenge to package my XLT body into a mid engine kart with A arm front suspension.

I'm not familiar with an XLT body, what is that? The challenge is the fun bit 😁 To be honest I actually don't like driving the cars, I just like the design and build journey

@@teamjuric XLT = extra, large, tall.

Oh dear, I should have read your original post again. I thought you were talking about a type of car not yourself 🤪

They are really great, I wouldn't say that racing is really the intention and I'm going a bit off the beaten track with mine compared to the more conventional cyclekarts. Glad you found the deep dive useful! What projects are you working on?

Thanks man, I'm so rusty with this whole thing I went back and did everything step by step from first principles. I've been fabricating the chassis, but it's been slow going with moving house and work. They're not common but there are a few people building them, would you consider building one? What motor did you use in the 7?

@@teamjuric yeah there are a few now but not 5 years ago, I probably would considder building one now but I want to build my 62 mini with honda driveline and suspension before I start any more random projects. As for the "cubman" I used a 125cc 3+1 mini quad bike motor so it has 3 forward speeds and reverse its more of a microcar than a gokart as it also has full lighting and instruments as well. I have the build series on my channel if you have time.

The mini with the Honda motor is a great combination. That's neat, I'll have a look at your vids!

Hi David, I do not think I was advocating doing anything other than following the guidelines to keep to the original intent of cyclekarting. I am just sharing some basic engineering and vehicle dynamics principles. You're drawing a long bow to suggest that using a car that was on the cusp of moving away from wire wheels or explaining how castor or trail works means we will end up with v12s in CycleKarts... Have you actually watched the videos or are you just assuming what my intentions are?

Thank you! I was fortunate enough to be taught by a real diverse group of amazing people and I hope I'm doing them justice by sharing some of that knowledge and if you read the comments I'm learning lots from the community. Being curious and having the community mindset is so important. If there are other things you're interested in please let me know. I'm using the cyclekart as the basis for this (which has aggrieved some people) however all these principles apply to any vehicle, if I had the money and time it would actually be a motorbike engined open wheeler that would be the project basis, but this project is a great compromise of cost, complexity and fun!! Do you have a project you're working on?

Great comment. I'm from Brazil and amazed how friendly and talented cyclekart groups are. Hope someday I have one. Congrats to you ali.

It is a great community! What inspiration car would you base your cyclekart on?

Thank you for watching, hopefully it gives you some food for thought

Thanks for the advice, the duty of this car is low im not super concerned about longevity. I'm going to see what the installation stiffness of the wheels is specifically at the hub, it is where most wheels fail. Yeh the chain tensioning is not my strong suit but I still like having positive adjustment of the chain at static and then you can do the fine adjustment with a sprung chain tensioner. You sound like you've build a few cyclekarts?

@@teamjuric Actually, I haven't but been thinking about building one as I'm too old to be falling down at high speed nowadays. The wheels rarely fail on bike (C50-CB100), even when overloaded a bit but when smaller hubs are used to save weight on race bikes they crack , particularly if 'ventilated' to aid cooling. AHRMA (American Historic Racing Motorcycle Association) requires drum brakes on all pre-1974 bikes (which can fade pretty quick compared to discs). I have melted the centres out of brake pads when 'trying a bit' using organic instead of sintered pads (even if organics work much better in the wet) Hubs have a pretty easy fix though, have a shrink fit plate to support outer edge of brake drum so it can't flex, either in drum or just on edge as basically the drum brake hub is a 'U' with bearing support on lower end extended to the open end Cheap way to go racing was get a street Honda CB350 and modify things as and when you could afford it, just stripping them down to basics shed around 60 lbs (there were over 3 million CB350's made and are still pretty common for a bike that went out of production in 1973) I was a motorcycle mechanic, shop manager, instructor, etc for 50 years but unlike most I actually studied things (failed engineer, couldn't do the math, even with a slide rule, LOL) You kinda lost me with your calculations even when they were well explained (the steering/weight transfer, etc was excellent, understood things much better since I tried studying it in the 80's and again in the 90's) I've seen a lot of broken stuff over the years, some I even broke myself 😁. Always try to figure out why things broke, often I could tell customers what they did, usually shocked the hell out of them as they were 'just riding along' All for now

I am building my car in my home garage at an extremely low cost, the minister of finance aka my wife wouldn't sanction anything ridiculous. It's a pity so many people see this as outside of the spirit, I'm not building it to win some non-existent competition. This endeavour has really given me some enjoyment and a nice cost effective creative outlet for me. I honestly thought the spirit of cycle karting is to have fun building your own car from scratch, joining a good community and learning something. You're not the first and won't be the last to comment like this, but I'm going to keep having fun building my car in my home garage and hopefully pass on some knowledge to people who are interested in how to design and build a car from scratch.

Same thing happened to go-karts.

There is a difference in that go karts were pretty much a competition from the start which brings money, this will never be anything other than a hobby as it's freedoms give you the chance to express yourself, the manifesto makes it clear this is not about competition etc...

Be under no illusions. A British person can design and build a rocket in their garden shed 👍

With ingredients stolen from under kitchen sink 😂​@@jrea424

Hi Joshy-Z, The thing I like about cyclekarts is that they're a great balance of cost, complexity and design freedom to make something really fun to build and drive! I've also found most people in the community are curious and very supportive I don't get too caught up in people's opinions on what is "real" and isn't (I'm more curious as to why they feel a particular way), just do your thing, fun is subjective, build something you enjoy. What body were you thinking of doing? With respect to the explanations, I'm documenting my process, it can be overwhelming but I try to lay it out in a more typical design process that a race car follows, but this doesn't need to be followed. You follow the process that makes sense to you. I guess because I go from first principles, hopefully for some who has a car with heavy steering, or has a really touchy brake pedal, can use these explanations to understand how to get to the bottom of it, maybe... I'm happy to talk through anything if you're interested. Thanks for your kind words too! Cheers, Phil

@teamjuric I want to build something that is a hybrid of a modern F1 car and the cars from the postwar era. No wings or serious aero, but basically a high nose car with a traditional by cyclekart standards rear. There wouldn't be wings or anything like that, but there might be some flow dynamics I would want to come from the floor I intended on building. I'm not good at the calculations of CFD, I just want to drive something I would actually like to see. I thought cyclekarts would be the way, but I guess there is some gatekeeping here, and it's disappointing. I just feel like if you can build it, you should be able to race it. These guys don't really even race, they just have fun. I don't understand why they have these limitations on who should be allowed to if you show up for the same reasons. There is no prize money. Cyclekarts should be building your fantasy car at economical prices. I'm not Adrian Newey.

That would be mega!!! I love the idea of mixing old and new, super cool idea. I think the gatekeeping is the minority, there would be some events to avoid but I'm sure the majority would be keen for something like what you're proposing. There is probably some reluctance due to the dickhe@d factor with people taking these things too far with competing as these cars are super freaking dangerous, but as long as it's clear it's not just about performance or trying to win some imaginary competition they are generally cool. Call it a cyclekart, do your thing, I cannot wait to see it!!

Hi Jeff, what aspects do you feel don't meet the CycleKart intent? I'm getting lots of feedback that it's not a cyclekart, but when I ask what specifically is the problem no one can articulate their position, so I'm feeling pretty confused by the commentary.

Hi, sorry I don't understand what you mean. Could you explain

@@teamjuric you could bundle all your videos in the series in order into a playlist available on a tab named “playlist’s” from your home page. I started watching video one and skipped back to the intro, then the team. Then video 1, 2, 3 ect. As they are currently presented all the videos in the series are out of order… Hope that makes sense?

@@Mannin_Watch_Time I appreciate the help, I'll fix this up to make it clearer

Hi Paul, what aspect do you feel I have moved away from the original concept? I do try to stick to the guidelines mostly. The rack is a 420mm unit from Ali express. a.aliexpress.com/_mPNa2cO

Thanks Andy. Great to hear you're enjoying it, and there is a lot to digest but feel free to reach out any time, happy to talk things through. Honestly I wouldn't have a clue how it would go on dirt. It would probably be too stiff and low, but I think the spool would definitely be decent for traction. I'll have to take it on the dirt to see what it does when I eventually finish it😂

Hi Jeff, unfortunately I am not selling the plans just yet but once I've completed with the first car I'll consider selling the plans

No trouble at all! Happy to answer any questions! In America there are many events, a few in the UK, but in Australia there aren't any currently. From my understanding they don't really encourage racing or competition, it's more an artistic project as the cars are pretty dangerous... We used to use LM76 slide rails, now the Monash team use Treotham drylin T rail guide, otherwise we did use some Jib rails one year from a yacht, but they're all essentially the same. T Rail with a dovetail and a linear bearing with mounts on it and a detent for positive locking.

@@teamjuric Thank you Sorry but a bit high brow for me Who supplies this equipment? Any chance of some photos? Building a front engined race car where this could be used for clutch brake and accelerator pedal assembly Thanks again David

This is the website for the linear rail. treotham.com.au/bearings/linear-technology/t-rail-guides This is some close ups of the Monash cars rails m.facebook.com/story.php?story_fbid=pfbid0FnxpiESYoCcgEwgiq3GypYGLZG2oR98Y9EEBDy7o9Gyg5fHWpkxirdFCGtvGBLP2l&id=185745901446670&mibextid=Nif5oz

@@teamjuric thank you much appreciated

Any time. Also my series just uses the CycleKart as the project basis, however everything I cover can be applied to any car

I'm happy with my project, it's the right cost and complexity for now. I'm getting back into the groove of the design and build. Ideally I want to then go back and build the hillclimb car, but it's too expensive for me right now so I'll stick to my Lotus... With respect to the UJs explanation, I had someone explain it to me when I was younger so maybe this will help someone else...

What I'd love to do for some excitement is to get a 4 cylinder cbr250 engine, spin that sucker up to 15k rpm!

I'm just applying engineering to my project.

This could nearly make me not bother to build one, whilst it might satisfy his ability to convert his very knowledgable engineering skills into practice it almost takes the fun out of wanting to make a car and discover it’s short comings for myself. I wish him well with his endeavours but as these are not ‘racing’ cars I cannot see the point evaluating the vehicle dynamics to this degree.

@metalmicky Hi Micky, the beautiful thing about this hobby is that you do what you feel comfortable with and most importantly have fun. I didn't make these videos to ruin the hobby for anyone. I appreciate your feedback and I'm sorry that it wasn't for you. This isn't for everyone, it's unfortunate that the project Ive used to document my design and build hobby is so contentious and gatekept, but don't let me be a barrier to your enjoyment. To be honest I'd much rather build a hillclimb car, but it's expensive and this is fun, so I'll keep doing the thing that I get great enjoyment from. Hopefully you have a great learning experience and we can one day have a beer and a laugh over our different ways of seeing the world.

I wouldnt recommend it, they aren't very safe or practical

Not even close to legal.

A reverse trike would be easier to build and be legal.

Hi thanks for the comment. With respect to the stub axle perpendicular to the king pin, I only did that to illustrate the effect in an exaggerated case. Normally the stub angle would be 1-3deg relative to the horizontal depending on how much static camber you design into the system. Changing the stub angle will move the contact patch relative to the steering axis, but it's at the expense of camber so it is a parameter to adjust but it's generally not common to adjust camber for steering effort... On some setups like gokarts you can only adjust camber with kpi, but I like to decouple these two as they have different effects.

@@teamjuric Ah, understood! Now it makes sense. Sorry 🙂

All good! I like having these conversations, I always go back over the content and make sure what I've presented is somewhat accurate, as I'm very rusty with some of this stuff!

Thank you!

Glad it was helpful!

Thank you!!

@Fur8002. Seconded.

@@pommunist really glad it was helpful

CycleKarts are a nice middle ground, there isn't a competition as such but you can make of it whatever you want. Yeh I shudder to think what the costs of competing in hillclimbs are now... I still like watching them, but it might be a bridge too far for me now unfortunately

Hannah's Bug

Thank you, by the time I'm done my kids are going to be teenagers so maybe they'll be finishing it off

A friend with older kids built a playhouse and his tip was to build mine with adult headroom and 25 years on we're still using it. I think its a smart move building a cyclekart not a kids size, at least not the size they are now. Hopefully you'll ALL get to finish it and enjoy it, and others down the line.

Thanks mate! Be aware that I'm not doing the normal CycleKarts thing, I'm going a bit over the top with the engineering on some things so just keep that in mind. But the theory will apply to any car. If there is an area you want more detail on let me know and I can add it to a future video. The only caveat is that I'm slow at releasing new content as it takes me ages do the editing so it might be a little while...

Thank you

Hi Joe, Im very new to this so I'm very interested in your feedback. I try to keep the music as low as possible so it's not a distraction. However can you elaborate on your comment, what exactly about the music frustrates you?

Joe...have cup a tea and a lie--down. I thought it was absolutely fine. Can't please everyone huh 🤔

All good man, ask the worst thing to happen is we both learn something 😜

Hello, I got it off the CycleKarts Australia Official Facebook page as one of the 6 standards for CycleKarts in Australia. It specifies Maximum 40" track width from outside of tyres.

Hello, I got it off the CycleKarts Australia Official Facebook page as one of the 6 standards for CycleKarts in Australia. It specifies Maximum 40" track width from outside of tyres.

Hi Joseph, it's a very good point, and I had another think about it. It's not ground or axle height, it's way more complex in this set up simply because it's difficult to model the kinematics, since the deflection of the axle controls the path of motion. If everything was infinitely stiff then yes absolutely on the ground, however it's not going to behave like that so I don't see the need to use it in my roll stiffness calculation. For my calcs my assumption treated the pillow block bearings as a super stiff leaf spring set up. Again it's not realistic, but given the axle will deflect at some point along the length on the cantilevered side, the RC should be at some point above the ground approximately at the centre of bending. So it won't be either, and since this was used to calculate roll stiffness, if you look at the sensitivity of the Rear RC between ground and axle height, it's about 10% shift of LLTD, not insignificant but it will be somewhere in-between. The final point is these wheels and tyres will deflect like crazy to lateral forces, the roll centre will move more from contact patch movement than deflection of the axle... I will be doing a proper roll resistance test and axle system deflection testing to actually see what the behaviour will be to get some credibility in the numbers and revise from there.

@@teamjuric Hi Phil. I've been rethinking it too, and came to pretty much the same conclusions, though I'm not as fluent in the language of suspension. Thanks for being open minded. I learned a lot from your first two videos and I'm sure third will be as good.

Hi Phil. I had another think too, and I think the dynamics of the situation overrule me .The load transfer in a corner will be high. and the roll lever will be from the ground to CG height. With rear weight bias, no diff and not much front roll stiffness this means a strong tendency to oversteer. looking at it this way I think the rear roll center should be considered to be at CG height. I would think you'd need a very stiff front anti roll bar to balance the front and rear grip.@@teamjuric

Its funny, the more degrees of freedom you remove the more difficult it is to predict... This is another complex issue which I'm hoping to elaborate on in the next video. In my initial suspension rate calculation I assumed an infinitely stiff chassis, but given how stiff the suspension rates are, the chassis won't be stiff enough to maintain that level of fidelity required. What that results in, is the chassis acts as a torsional spring in series to the suspension springs and reduces the stiffness of the overall roll rate, and this isn't easy to predict what suspension spring changes will do to the balance/roll stiffness distribution. In short so many unknowns especially tyres, I need to build it, design in adjustment, do bench testing and then dynamic validation. It's going to be a fun process but a long one!!

Glad you liked it! keep asking questions, be curious!!