Great video! I'm a mech eng undergrad, and i design the kinematics, dynamics and mechanical components of an offroad race vehicle at school. Hoping to become a mountain bike frame designer when I graduate, love your content!
Muchas gracias André. Es importante aprender de nuestros errores, pero lo es más, cuando de nuestros errores hacemos que los demás aprendan también de ellos. Enhorabuena.
Could you do a video discussing the different styles of linkage and frame builds when it comes to slopestyle bikes like Morpheus, transition, Pivot, specialized, canyon, etc. I run mine with 150 up front and 100-107 rear. It's my everything bike here in Michigan. It rips majority of our hearty rugged trails like a boss. I've kind of made it my Enduro/FR bike. But I'm amazed with how much that rear shock can swallow for so little travel as Enduro/FR.
Great explanation, i'm sure we have all learned more about suspension pivots design now thanks to this error! glad others were willing to help you out and in return help us all out. Love your work!
There is some mixing of concepts here, of which the Trek bike analysis at 12:45 is a good example. There cannot be two virtual pivot points for a movement. What happens there is the first "ic" is the real and unmistakeable pivot point of the wheel, which determines pedalling/suspension dynamics. The second "ic" determines the braking/suspension dynamics. However on the previous examples the same thing happens, and there are two "ic's" as well. Only on single pivot bikes in which the brake stays are on the same structure that connects the rear wheel to the main pivot, are these two "ic's" the same. On all suspension systems that involve linkages there will be two ic's as well, or to put it more clearly there will first be a physical pivot point or a virtual pivot curve. Not a virtual point because with linkages the rear axle will not follow a perfectly round trajectory like a physical pivot point does, the wheel path curve will change in radius, so there will be a curve of instant pivot points so to say. Besides this physical pivot point or virtual pivot curve there will be the "ic" (as it's being referred to here) which determines the relationship between the brake stays and the brake disc. This second "ic" is the only one that is determined on the other examples. The virtual pivot curve is not shown.
The virtual pivot curve is also the primary factor for determining the interference between pedalling forces and the suspension. All tech lingo or marketing talk aside, it all lies there. Manufacturers can use very seemingly different suspension systems, with different explanations, which in the end achieve the same virtual pivot curve. Suspension squat and anti-squat come from the relationship between the virtual pivot curve (or physical pivot point), the chainring(s) and the rear cog(s). The other variables come from how the suspension system compresses the rear shock, which is reflected not only on the suspension characteristics but also on the pedalling ones. But the primary factor for pedalling is the location or path of the physical pivot point or virtual pivot curve.
Awesome video! Very informative. I need to watch the suspension series again as I just bought my new bike and will want to tune it nicely. Ended up getting the 2016 Trance 1. Thanks man!
Hi André, Impressed by the level of detail in the video. Need your suggestion, in a case where a swing-arm is mounted to a rocker arm and the rocker arm is mounted to the frame, then the shock-absorber is placed between the swing-arm and the frame. I have mailed you a reference image, could you please help me in finding the IC, for this scenario.
I'm a bit confused, because at 10:37 you show that the correct anti-rise value (the steeper line) for the Kona is almost twice the incorrect value (which was a shallower angle). And if I read that right, an anti-rise value near 100% means the suspension is affected very little by braking. Yet earlier, when talking about the FSR (which had a much shallower angle compared to the Kona), you said that a lower angle meant more anti-rise, which I find hard to believe as lots of modern bikes have an IC close to the bottom bracket, which is a steeper anti-rise line, and I doubt manufacturers are making bikes that are worse under braking.
It all depends on where the brake caliper is mounted. In Kona it is mounted on chainstays, so it works as a single pivot (Antirises near 90-100%). On Horst links the brake is mounted on seatstays, so there is less rotation of caliper around the disc leading to lower anti-rise. I think I explained that well in the final part of the video (on ABP example). Having an higher anti-rise preserves better the geometry (anti-rise of 100% means that if you brake with the rear brake only in the parking lot the bike won't rise the rear suspension...you can test that... on horst-link if you brake rear wheel only, the shock extends slightly pitching the bike slightly forward). There is no conclusive study showing that a lower or higher anti-rise is better or worse... for instance on motorbikes the anti-rise is usually higher than on MTB, in particular on Horstlinks MTB. Cheers
Olá André! Sou de Brasília e soube que você é de Portugal através do canal do Henrique do Pra Quem Pedala. Estou aprendendo muito com seus vídeos. A complexidade dos sistemas de suspensão traseira dificulta muito a nossa escolha. Quero comprar uma bike full suspension e por isso estou estudando. Quero optar por um sistema simples, sem muitas regulagens e com pouca manutenção. Fico muito inclinado a optar pelo sistema VPP da Santa Cruz. Se possível dê sua opinião sobre esse sistema. Um grande abraço e parabéns pela excelência dos vídeos.
O VPP da Santa Cruz é muito bom para pedalar, mas hoje em dia quase todas as bikes estão optimizadas para pedalar bem (anti-squat 100%). Um simples singlepivot pode pedalar bem se o pivot estiver no sitio certo. Se a bike for para XC entao nao precisa muito de se preocupar com a progressividade, e isso torna mais simples a escolha. Se for para Enduro / DH aí vai precisar de uma bike progressiva e para escolher tem de analisar caso a caso. Abrç
Nice explanation of this IC. Now that is called going to the "heart" of suspension design! In coming videos pls explain how IC effect pedal bob, anti raise and how that dynamicly changes true the travel. p.s. how is possible for trekABP(pedal bob) that both IC centers are valid? Isnt ABP like single pivot? I'm sure many would love to see analyze for Specialized Epic WC 29 2016 and Camber 29 2016. Thx for your effort:)
+racittaj Yes, I will talk more about this stuff. This was just the basics (still 17 min long...). Trek ABP (or Split Pivot) work as virtual pivots on the braking side (because brake floats on the seatstay), and work both as single pivots or virtual pivot on the pedaling side (because wheel is attached both to seat- and chain-stay). To determine the anti-squat % you need to do a line that crosses the rear wheel axle and the IC, and then, you determine the intersection of that line with the chain (that point is the IC for anti-squat). On ABP if you do a line crossing both the wheel axle and the IC, that line will always pass on the main pivot. Thus, either you consider ABP as a single pivot or a virtual pivot, the result will be exactly the same for the anti-squat (not on the anti-rise). And that's the beauty of the method. The closer the rear pivot is from the wheel, the closer the bike will work as a single pivot for the anti-squat. On VPP that rear pivot is closer to the BB than the rear wheel, thus, those bikes can achieve a very different shape and behavior on the anti-squat profile. If you saw my analysis videos for Nomad III or Intense Uzzi, for instance, you can see that anti-squat graphic can have a very different shape when compared with FSR or single-pivot for instance. Bye.
its okay mate.i still appreciate all the videos that you created,btw i got my uzzi and the geometry of that frame and the vpp suspension has a big difference than my scott genius lt..all i can say is youre right scott genius is smooth on a flowy trail but uzzi is really beast and great in rough and technical trail and the top tube is much lower that really gives you a room to shred your bike and be more comfortable,its just like more similar to downhill bike but it can climb. by the way are you going to make another table of bike progressiveness because of corrections?
+julius victor Tupas Hi Julius. The error affected mainly the anti-squat and anti-rise of those 8 bikes in particular, the progressivity was minimally affected by the mistake. Nice to hear that about the Uzzi. You can drop that 1 meter to flat without bottoming out eheh :D
+andrextr yeah you're right,do you think it is much better to use air suspension to uzzi and is there any good difference? Also Just a bit curious to scott genius lt progressiveness,is it way improve or still regressive bike?
Hey Andre ! You make great videos, I was asking me a question, which software do you use to simulate the movement of the bike in relation to the suspension movement? Thanks !
Andre, what is the % number for anti-rise relative to? Is 100% when the line is 45°? Also, same question for anti-squat. Where does the % number come from? Thanks again for all the videos!
+Brent Williams Hi. I will talk about that in the future, but basically you have to draw a vertical line crossing the front wheel axle. The heigth of the point where the AS or AR line crosses with that vertical line gives you the % value, where the 100% is the center of gravity (CoG) height. Since the wheelbase length is similar to CoG height (~1.1m), then a AR or AS line with around 45º corresponds to a 100% AR (or AS). You can see here these picture to help visualize. Keep in mind that the AS line is calculated differently than the AR line. www.pinkbike.com/photo/13269641/
Hi Andre. Good explanation, but i miss something. When you add model at linkage you not add IC value, it's come from program. So mistakes which you talk is based on wrong pivot mark /like Swingarm-linkage pivot for Swingarm model/ or i am not understand well.
+George Krastev In the program you can define the type of linkage. If you define it as a horst-link the software puts the wheel and the brake on the seatstay (moving IC), if you put it as a swingarm 4-bar the software puts the wheel and brakes on chainstay and it simulates as a fixed IC on main pivot (the case for the Kona Operator, for instance). And that was the problem. I though Operator would work as a virtual pivot, which is not the case since the wheels and brakes are not floating in the seatstay. Looking back it was a basic error, but for someone that is far from being a engineer it made sense back then... :) Bye
+andrextr this clear my question. I am not moving at this direction Horst VS Swingarm. Swingarm is more single pivot + swingarm , but i hate add this kind of suspension at linkage. Sometimes "enginеers" make some interesting developments. Keep make more videos , make a good work.
+rexson Yes, the way to determine de IC and anti-rise is the same since VPP and DW are both dual short links. However there are some differences between both. In DW the links rotate clockwise, while in VPP the lower link rotates clockwise and the upper counterclockwise. This changes the shape of anti-rise curve. For instance, if you saw my video analysis of SC Nomad III, you can see that the Anti-Rise decreases hugely on the last part of the travel (from +60% to -80%), because the links became parallel and pointing down at the end of the travel, so the IC goes to 30 meters forward and 10 meters below the ground. BTW, a negative anti-rise means that the suspension extends with braking forces (aka Brake-Jack), which is bad, but in this case, it only happens at the end of the travel (non-braking zone). So, different configurations means different behaviors. Bye :)
+rexson you can see here the counterclockwise rotation of upper link in VPP. Look how parallel the links are at bottom-out. www.bikeandride.cz/wp-content/uploads/2015/02/Santa-Cruz-Nomad-VPP.jpg
Nice video Andre, but hold on)) When you say simulating Trek suspension with IC in main pivot location and in virtual point give the same result do you mean AS and pedal kickpack? How come? I'd assume axle paths (and hence chaingrowth and all the stuff) would be different.
+Kostya Cherepovskyi It will give the same result in antisquat. Antisquat depends on chain angle and swingarm angle. Using the main pivot or the ic gives the same swingarm angle, thus it gives the same antisquat result. This is true in ABP because the wheel is connected to both chain stay and seat stay. So both methods will give the same result (which make sense). The kickback is a result of chain growth (and depends on cog sizes). Chain growth is just how the distance changes between BB and rear axle. Bye
> Antisquat depends on chain angle and swingarm angle. Angles only? Or their intersection point position relative to IC? This would be different based on which one you choose. Also when I think about chaingrowth I realize it determines AS as well as kick-back. Growing chain basically means that when you pull it you're extending suspension back, which is AS effect by definition, right?
+Kostya Cherepovskyi Yes, intersection. But intersection is affected by the angles ;) steeper swingarms result in higher AS while steeper chain line results in lower AS. Regarding the last point what you said is true but there is another detail which is important on high pivot bikes. The AS is a result of chain pulling and also driving force. On traditional bikes this driving force is low and AS cames mostly from chain, while in high pivot bikes this driving force is important. If you imagine a steeper swingarm, when you accelerate the wheel axle moves forward and the swingarm has the tendency to rotate counter clockwise extending suspension (antisquat). On high pivot bikes and on motorbikes, you can get good AS without virtually chain growth and no kickback (the AS cames mostly from driving force and not from chain pulling). I'm planning to do a video about this but I've been busy lately. Bye
I got your idea of driving force as another source of AS effect. Regarding chain related forces and the same result for two different ICs I'm still not sure, though, and let me explain why with this: i.imgur.com/f0GyT2e.png On this picture you can see same AS point (intersecting chainguide and chainline, red) but different ICs (black). And as far as I understand AS values are connected to IC position: 'good AS zone' (yellow) starts form IC and goes counter-clockwise. In case A you see that AS point is in good zone while in case B it might or might not. Am I missing something?
+Kostya Cherepovskyi On linkage software you get the same AS on Trek bikes either you simulate as a single pivot (swingarm 4bar) or a virtual pivot (Horst link). On your picture the red point is the same, thus the AS is the same. This only true on Trek bikes. On Horst link bikes you have to use virtual IC and in other bikes where the wheel is on chain stay you need to use main pivot as IC. Keep in mind that the swingarm line is the line that connects rear axle with IC. The interception point corresponds to the swingarm and chain line interception. See my antisquat episode. Since on Trek the rear axle is concentric with Horst link pivot, you get the same result on AS using both IC (otherwise it wouldn't make sense to get different results since the wheel is connected to both chain stay and seat stay). Bye
Você falou lá no Pra quem Pedala : "Obrigado pela partilha !! :) Apesar do sotacão da eslováquia eu sou de Portugal eheheh Valeu! Abraço" . Versão em português ou pelo menos com legenda em português vai ganhar mais seguidores! Mandou bem! Abraço!
Eu nos primeiros videos fazia legenda, mas demora muito tempo fazer legenda e sincronizar tudo !! Infelizmente este ano não tenho tido tempo nem para andar de bike :(
So If I understand correctly, you have to predefine correct frame type in Linkage, to get correct results... ? Otherwise it will calculate IC incorrectly, even when model visually works as it should.
So, if the caliper moves not much then does the rear wheel rise up when rear breaking? and if the caliper moves pretty much then the rear wheel doesn't rise up and shock is stiff even though the shock is not compressed?
+jungjoon choi Im planning a video about this, but I'm a bit busy these days, but when the caliper don't moves much it means that the braking won't affect the rear suspension, however, when you brake the rear wheel your weight shifts forward unloading the rear end and causing the rise of the suspension (you can easily test this on a parking lot...When you apply the rear brake on all Horst link bikes with an horizontal rocker arm, the shock extends). On single pivot bikes (and other designs where the caliper rotates more, or even in Motos..) the antirise is higher meaning that braking force cause the squat of rear suspension. When antirise is close to 100% this squat force is similar to rise force, so when you brake the suspension don't move and geometry don't change (you can easily see this on parking lot on a single pivot bike). Bye
+Clefrigh Summum and Session analysis is correct (they both have a virtual pivot). All the incorrect bikes are present on the table in the beginning (and the videos for those were already deleted)
Good day... Can you help me with something? Can you tell me please, if it is 'ok' to have different suspension travel in the front & rear & if yes, what the limit may be? Also can you tell me if one can use a larger or smaller rear shock that stock? (& if yes, by how much) Thanks...
+Marvin Connell Hi, it depends on the bike but in many cases you can have a front suspension with slightly more travel than the rear suspension. You can find that information on the owner's manual of the bike. For instance, many bikes with 150mm of rear travel can handle up to 160mm of fork travel. For the rear shock, it's not recommended to change the eye-to-eye length or the stroke of the shock (because that leads to a drastic change in the geometry and in some cases the rear triangle or the wheel can hit the main frame). Bye
+andrextr What about less travel in the front than the rear? I should explain - I have a 100mm hardtail & am looking into getting a full suspension frame with 150\160mm travel... I would like to simply swap parts but same is limited & forks of equal travel are expensive... So I'm looking at alternatives... As of yesterday I'm even considering using a rear shock with less travel(eye to eye) - any thoughts on that? THANK YOU for your responses... =]
Reducing the shock length can cause the wheel or the rear triangle to hit the main frame during a bottom-out (since the shock length is smaller it means that the suspension moves further). So, it depends on the clearance of the frame, but I don't think is a good idea. Having a 100mm fork in a 160mm bike does not have any problem, but the bike will feel unbalanced... There are some 130-160mm forks that are not much expensive, such as sektor/recon silver, or the heavyweight RS Domain (you can bought one under 200$ / €). Or a second hand one. Or Suntour forks. Bye
is the instance pivot changing if I set the fork or rear shock sag differently in virtual pivot bike? and so are the results including anti squart, anti rise..?
The IC moves during rear suspension movement, and in some bikes this makes the AS and AR to change drastically during suspension travel. The front suspension travel can change a bit the IC, because the bike tilts forward, but this is a detail.
GT Force is a swingarm 4-bar (similar to single-pivot), thus, the IC is fixed on the main pivot. Given it's high position, GT Force has an higher anti-rise (around 120%). Bye
+Prospect Visuals Yes, that's why. Sorry. However, in the case of Commencal the error almost didn't affect the results. I might re-do the video again in the future. But, with the correction, both V4 and V3 are very very similar. Almost identical. Anti-squats close to 100%, anti-rise close to 90%, and progressivity of 20% in both cases. The differences are thus visuals, geometry and probably weight / rigidity. Bye
+jungjoon choi When it's zero the suspension is not affected at all by the braking forces. When it's very high, like 150% for instance, braking will compress significantly the rear suspension under rear braking, stiffening the shock and making it to rebound slower. Overall these effects are not very drastic since they are limited by the tire traction (when the tire skids you reached max effect). The shock won't fully lock out, that's only some exaggerated marketing claims. Bye
I heard somebody said ' brake jack' in which suspension is extended and locked when pulling the rear brake. what is brake jack? is this related to the rear brake squat? or is it refering to dive of fork when fornt braking?
Brake Jack is when the braking force extend the suspension. That happens in very rare cases when the IC is located behind the rear wheel. The Lawwill design is one example of that. But even in that design the brake jack is solved by mounting the brake caliper in a floating brake arm (see Rotec Lawwil for instance). For most bikes what you get is brake squat and not jack. Bye
+robertr32 Medira one twenty has the wheel and brakes on the chainstay, therefore it will work as a singlepivot, and the IC is on the main pivot (near the bottom bracket). Bye
+andrextr hello again. could you tell me what is the force neded to bottom out my rear shock on my merida one twenty with 20% and 25% sag at my 90 kg with gear. thank you.
+Omar Dakar Yes, this is the way that the software calculates the anti-squat and anti-rise. If you want to see those lines you have to select the option at the top left corner to show them. Bye
@@andrextr Awesome! Thanks for the reply. $25 Isn't bad at all for how powerful that program looks. I'm really curious how my budget build bike stacks up to these other bikes. If you ever want to make a video of an Iron Horse - Warrior 3.3, I could provide a photo and all the specs.
+Sergio Rebuffo Hi. I build a picture to answer your question (see below). Keep in mind that IC moves during suspension travel. Bye ep1.pinkbike.org/p5pb13444350/p5pb13444350.jpg
IC looks like a baloney to me. Take a new Demo for example and do a little thought experiment. Lets modify rear triangle element that holds rear axle but IC will stay the same. Lets just move rear axle is very very very close to low linkage bearing. IC would stay the same because we didnt change linkages. After modification: rear path moves practicly single pivot path of lower linkage, and has nothing to do with IC.
+maqusss Yes, moving the rear axle doesn't change the IC. However, it would change the anti-squat and also anti-rise (because for anti-squat calculation, you need the IC and the position of the rear axle also), and for anti-rise the rear wheel contact point position is also required, and by changing the rear axle you also change that. I did your experiment in Demo, and for instance, the anti-squat for a 36T x 18T droped from +35% to -65% (a reduction of 100%). The difference is anti-rise is much lower though (5%). The closer you put the rear axle to the rear pivot the closer the bike will work as a singlepivot for the anti-squat. In the case of Trek ABP / Split-pivot, as I said in the video, you get the same anti-squat result either if you simulate it as a moving IC or as a fixed IC at the main pivot... So, it looks like baloney at first, but at the end it makes sense :) I will talk more about the IC, braking and pedaling in future videos, so I hope it will make sense to you. Bye
+andrextr thank you for explanation. Im still digint into this anti squat and anti-rise. What i find tricky is case when IC is not fixed point. Thus its hard to see why rear wheel should rotate around IC.
Yes, I understand you. And it's not easy to visualize it, but I will try to convince you. With a IC fixed you have a perfectly circular axle path. With a moving IC, the center of rotation changes, and thus the wheel path is no longer perfectly circular. See this crazy example that I did (link below). As you can see, the wheel path changes from a vertical shape at the beginning to almost an horizontal shape at the end. That's because the center of rotation changes drastically it's position, and the wheel is almost moving horizontally at the end (the IC at the end goes to the top of the rear wheel). I'm not an engineer, but I hope this example can convince you. Bye :) ep1.pinkbike.org/p4pb13431926/p4pb13431926.jpg
Your putting coals in the fire of suspension myth. It’s a bicycle! Look at contact patch movement of the rear wheel through travel and forces on the shock through travel. Fixed and moving pivot design just get close results with different approaches. Best tune for rear suspension? Chain guide.
thanks for making the mistake I have learned even more things about mtb suspension and you explain it very well indeed
+jason cramp "a blessing in disguise" :D
Great video! I'm a mech eng undergrad, and i design the kinematics, dynamics and mechanical components of an offroad race vehicle at school. Hoping to become a mountain bike frame designer when I graduate, love your content!
+Max Scully Thanks man! Wish you the best of luck (when you start designing frames remember to send me one for testing eheheh).
Really good stuff as always. Keep up the great work!
Seb from Bikeradar.
+Seb Stott Thank you Seb! Bye :)
Wonderful series, my friend. Information dense, smooth flow across topics...just brilliant. Please do more series such as these, if possible.
Thanks! I would like to do more, but I don't have much free time at the moment :(
Muchas gracias André.
Es importante aprender de nuestros errores, pero lo es más, cuando de nuestros errores hacemos que los demás aprendan también de ellos.
Enhorabuena.
+Josep Barberà Gracias Josep! Un saludo.
Don't worry about it we all make mistakes! Your analysis is still incredible!
+ali mccheyne Thank you for your words :) Bye
Wow I finally understand trek ABP, definitely wasn't getting it before. Thank you so much.
This video changed a lot in my perception of bikes! Thank You! Subscribing and waiting for more!
Could you do a video discussing the different styles of linkage and frame builds when it comes to slopestyle bikes like Morpheus, transition, Pivot, specialized, canyon, etc. I run mine with 150 up front and 100-107 rear. It's my everything bike here in Michigan. It rips majority of our hearty rugged trails like a boss. I've kind of made it my Enduro/FR bike. But I'm amazed with how much that rear shock can swallow for so little travel as Enduro/FR.
Great explanation, i'm sure we have all learned more about suspension pivots design now thanks to this error! glad others were willing to help you out and in return help us all out. Love your work!
+Greg Rosich Thanks man! :)
There is some mixing of concepts here, of which the Trek bike analysis at 12:45 is a good example. There cannot be two virtual pivot points for a movement. What happens there is the first "ic" is the real and unmistakeable pivot point of the wheel, which determines pedalling/suspension dynamics. The second "ic" determines the braking/suspension dynamics. However on the previous examples the same thing happens, and there are two "ic's" as well. Only on single pivot bikes in which the brake stays are on the same structure that connects the rear wheel to the main pivot, are these two "ic's" the same. On all suspension systems that involve linkages there will be two ic's as well, or to put it more clearly there will first be a physical pivot point or a virtual pivot curve. Not a virtual point because with linkages the rear axle will not follow a perfectly round trajectory like a physical pivot point does, the wheel path curve will change in radius, so there will be a curve of instant pivot points so to say. Besides this physical pivot point or virtual pivot curve there will be the "ic" (as it's being referred to here) which determines the relationship between the brake stays and the brake disc. This second "ic" is the only one that is determined on the other examples. The virtual pivot curve is not shown.
The virtual pivot curve is also the primary factor for determining the interference between pedalling forces and the suspension. All tech lingo or marketing talk aside, it all lies there. Manufacturers can use very seemingly different suspension systems, with different explanations, which in the end achieve the same virtual pivot curve. Suspension squat and anti-squat come from the relationship between the virtual pivot curve (or physical pivot point), the chainring(s) and the rear cog(s). The other variables come from how the suspension system compresses the rear shock, which is reflected not only on the suspension characteristics but also on the pedalling ones. But the primary factor for pedalling is the location or path of the physical pivot point or virtual pivot curve.
Congrats on the recognition of some industry insiders!
Awesome video! Very informative. I need to watch the suspension series again as I just bought my new bike and will want to tune it nicely. Ended up getting the 2016 Trance 1. Thanks man!
I have a 2019 Trance 1.5 (GE) - same story, wanted to know how this bike works ;)
Hi André,
Impressed by the level of detail in the video.
Need your suggestion, in a case where a swing-arm is mounted to a rocker arm and the rocker arm is mounted to the frame, then the shock-absorber is placed between the swing-arm and the frame. I have mailed you a reference image, could you please help me in finding the IC, for this scenario.
I’m thoroughly enjoying your videos
Thanks
It was great to see how you analyse bikes, really interesting!
I'm a bit confused, because at 10:37 you show that the correct anti-rise value (the steeper line) for the Kona is almost twice the incorrect value (which was a shallower angle). And if I read that right, an anti-rise value near 100% means the suspension is affected very little by braking. Yet earlier, when talking about the FSR (which had a much shallower angle compared to the Kona), you said that a lower angle meant more anti-rise, which I find hard to believe as lots of modern bikes have an IC close to the bottom bracket, which is a steeper anti-rise line, and I doubt manufacturers are making bikes that are worse under braking.
It all depends on where the brake caliper is mounted. In Kona it is mounted on chainstays, so it works as a single pivot (Antirises near 90-100%). On Horst links the brake is mounted on seatstays, so there is less rotation of caliper around the disc leading to lower anti-rise. I think I explained that well in the final part of the video (on ABP example). Having an higher anti-rise preserves better the geometry (anti-rise of 100% means that if you brake with the rear brake only in the parking lot the bike won't rise the rear suspension...you can test that... on horst-link if you brake rear wheel only, the shock extends slightly pitching the bike slightly forward). There is no conclusive study showing that a lower or higher anti-rise is better or worse... for instance on motorbikes the anti-rise is usually higher than on MTB, in particular on Horstlinks MTB. Cheers
Thanks for sharing this information...very good explanation
Olá André! Sou de Brasília e soube que você é de Portugal através do canal do Henrique do Pra Quem Pedala. Estou aprendendo muito com seus vídeos. A complexidade dos sistemas de suspensão traseira dificulta muito a nossa escolha. Quero comprar uma bike full suspension e por isso estou estudando. Quero optar por um sistema simples, sem muitas regulagens e com pouca manutenção. Fico muito inclinado a optar pelo sistema VPP da Santa Cruz. Se possível dê sua opinião sobre esse sistema. Um grande abraço e parabéns pela excelência dos vídeos.
O VPP da Santa Cruz é muito bom para pedalar, mas hoje em dia quase todas as bikes estão optimizadas para pedalar bem (anti-squat 100%). Um simples singlepivot pode pedalar bem se o pivot estiver no sitio certo. Se a bike for para XC entao nao precisa muito de se preocupar com a progressividade, e isso torna mais simples a escolha. Se for para Enduro / DH aí vai precisar de uma bike progressiva e para escolher tem de analisar caso a caso. Abrç
Nice explanation of this IC. Now that is called going to the "heart" of suspension design! In coming videos pls explain how IC effect pedal bob, anti raise and how that dynamicly changes true the travel.
p.s. how is possible for trekABP(pedal bob) that both IC centers are valid? Isnt ABP like single pivot?
I'm sure many would love to see analyze for Specialized Epic WC 29 2016 and Camber 29 2016.
Thx for your effort:)
+racittaj Yes, I will talk more about this stuff. This was just the basics (still 17 min long...). Trek ABP (or Split Pivot) work as virtual pivots on the braking side (because brake floats on the seatstay), and work both as single pivots or virtual pivot on the pedaling side (because wheel is attached both to seat- and chain-stay). To determine the anti-squat % you need to do a line that crosses the rear wheel axle and the IC, and then, you determine the intersection of that line with the chain (that point is the IC for anti-squat). On ABP if you do a line crossing both the wheel axle and the IC, that line will always pass on the main pivot. Thus, either you consider ABP as a single pivot or a virtual pivot, the result will be exactly the same for the anti-squat (not on the anti-rise). And that's the beauty of the method. The closer the rear pivot is from the wheel, the closer the bike will work as a single pivot for the anti-squat. On VPP that rear pivot is closer to the BB than the rear wheel, thus, those bikes can achieve a very different shape and behavior on the anti-squat profile. If you saw my analysis videos for Nomad III or Intense Uzzi, for instance, you can see that anti-squat graphic can have a very different shape when compared with FSR or single-pivot for instance. Bye.
its okay mate.i still appreciate all the videos that you created,btw i got my uzzi and the geometry of that frame and the vpp suspension has a big difference than my scott genius lt..all i can say is youre right scott genius is smooth on a flowy trail but uzzi is really beast and great in rough and technical trail and the top tube is much lower that really gives you a room to shred your bike and be more comfortable,its just like more similar to downhill bike but it can climb.
by the way are you going to make another table of bike progressiveness because of corrections?
+julius victor Tupas Hi Julius. The error affected mainly the anti-squat and anti-rise of those 8 bikes in particular, the progressivity was minimally affected by the mistake. Nice to hear that about the Uzzi. You can drop that 1 meter to flat without bottoming out eheh :D
+andrextr yeah you're right,do you think it is much better to use air suspension to uzzi and is there any good difference? Also Just a bit curious to scott genius lt progressiveness,is it way improve or still regressive bike?
how you liking that 650b uzzi brother? fill me in
Hey Andre ! You make great videos, I was asking me a question, which software do you use to simulate the movement of the bike in relation to the suspension movement? Thanks !
Tks. Linkage X3 i have a vídeo about the software .
@@andrextr Ok ty, gonna check that !
Thanks a lot for visual explanation :) Like to see theory in praxis..
Btw. is there Cannondale Jekyll listed in your queue of kinematics?
+Lukáš Bartošek Yes it is... I will try to address that bike one day. Bye
Andre, what is the % number for anti-rise relative to? Is 100% when the line is 45°?
Also, same question for anti-squat. Where does the % number come from?
Thanks again for all the videos!
+Brent Williams Hi. I will talk about that in the future, but basically you have to draw a vertical line crossing the front wheel axle. The heigth of the point where the AS or AR line crosses with that vertical line gives you the % value, where the 100% is the center of gravity (CoG) height. Since the wheelbase length is similar to CoG height (~1.1m), then a AR or AS line with around 45º corresponds to a 100% AR (or AS). You can see here these picture to help visualize. Keep in mind that the AS line is calculated differently than the AR line.
www.pinkbike.com/photo/13269641/
+andrextr Awesome, looking forward to that video. Thanks again!
Hi Andre. Good explanation, but i miss something. When you add model at linkage you not add IC value, it's come from program. So mistakes which you talk is based on wrong pivot mark /like Swingarm-linkage pivot for Swingarm model/ or i am not understand well.
+George Krastev In the program you can define the type of linkage. If you define it as a horst-link the software puts the wheel and the brake on the seatstay (moving IC), if you put it as a swingarm 4-bar the software puts the wheel and brakes on chainstay and it simulates as a fixed IC on main pivot (the case for the Kona Operator, for instance). And that was the problem. I though Operator would work as a virtual pivot, which is not the case since the wheels and brakes are not floating in the seatstay. Looking back it was a basic error, but for someone that is far from being a engineer it made sense back then... :) Bye
+andrextr this clear my question. I am not moving at this direction Horst VS Swingarm. Swingarm is more single pivot + swingarm , but i hate add this kind of suspension at linkage. Sometimes "enginеers" make some interesting developments. Keep make more videos , make a good work.
Very comprehensive, thank you! :)
+Samorak's Technic Vehicles Thank you man :)
Thank you for sharing, enjoyed and learnt a lot!Kind regards
Awesome stuff!
awesome video. so would the anti rise line on a DW link bike be similar to a VPP bike?
+rexson Yes, the way to determine de IC and anti-rise is the same since VPP and DW are both dual short links. However there are some differences between both. In DW the links rotate clockwise, while in VPP the lower link rotates clockwise and the upper counterclockwise. This changes the shape of anti-rise curve. For instance, if you saw my video analysis of SC Nomad III, you can see that the Anti-Rise decreases hugely on the last part of the travel (from +60% to -80%), because the links became parallel and pointing down at the end of the travel, so the IC goes to 30 meters forward and 10 meters below the ground. BTW, a negative anti-rise means that the suspension extends with braking forces (aka Brake-Jack), which is bad, but in this case, it only happens at the end of the travel (non-braking zone). So, different configurations means different behaviors. Bye :)
+rexson you can see here the counterclockwise rotation of upper link in VPP. Look how parallel the links are at bottom-out.
www.bikeandride.cz/wp-content/uploads/2015/02/Santa-Cruz-Nomad-VPP.jpg
Nice video Andre, but hold on)) When you say simulating Trek suspension with IC in main pivot location and in virtual point give the same result do you mean AS and pedal kickpack? How come? I'd assume axle paths (and hence chaingrowth and all the stuff) would be different.
+Kostya Cherepovskyi It will give the same result in antisquat. Antisquat depends on chain angle and swingarm angle. Using the main pivot or the ic gives the same swingarm angle, thus it gives the same antisquat result. This is true in ABP because the wheel is connected to both chain stay and seat stay. So both methods will give the same result (which make sense). The kickback is a result of chain growth (and depends on cog sizes). Chain growth is just how the distance changes between BB and rear axle. Bye
> Antisquat depends on chain angle and swingarm angle.
Angles only? Or their intersection point position relative to IC? This would be different based on which one you choose.
Also when I think about chaingrowth I realize it determines AS as well as kick-back. Growing chain basically means that when you pull it you're extending suspension back, which is AS effect by definition, right?
+Kostya Cherepovskyi Yes, intersection. But intersection is affected by the angles ;)
steeper swingarms result in higher AS while steeper chain line results in lower AS. Regarding the last point what you said is true but there is another detail which is important on high pivot bikes. The AS is a result of chain pulling and also driving force. On traditional bikes this driving force is low and AS cames mostly from chain, while in high pivot bikes this driving force is important. If you imagine a steeper swingarm, when you accelerate the wheel axle moves forward and the swingarm has the tendency to rotate counter clockwise extending suspension (antisquat). On high pivot bikes and on motorbikes, you can get good AS without virtually chain growth and no kickback (the AS cames mostly from driving force and not from chain pulling). I'm planning to do a video about this but I've been busy lately. Bye
I got your idea of driving force as another source of AS effect. Regarding chain related forces and the same result for two different ICs I'm still not sure, though, and let me explain why with this: i.imgur.com/f0GyT2e.png On this picture you can see same AS point (intersecting chainguide and chainline, red) but different ICs (black). And as far as I understand AS values are connected to IC position: 'good AS zone' (yellow) starts form IC and goes counter-clockwise. In case A you see that AS point is in good zone while in case B it might or might not. Am I missing something?
+Kostya Cherepovskyi On linkage software you get the same AS on Trek bikes either you simulate as a single pivot (swingarm 4bar) or a virtual pivot (Horst link). On your picture the red point is the same, thus the AS is the same. This only true on Trek bikes. On Horst link bikes you have to use virtual IC and in other bikes where the wheel is on chain stay you need to use main pivot as IC. Keep in mind that the swingarm line is the line that connects rear axle with IC. The interception point corresponds to the swingarm and chain line interception. See my antisquat episode. Since on Trek the rear axle is concentric with Horst link pivot, you get the same result on AS using both IC (otherwise it wouldn't make sense to get different results since the wheel is connected to both chain stay and seat stay). Bye
Awesome content your putting out man thank you
As far as I'm concerned the best suspension ever made is the Jamis Dakar with the MP2 suspension.
Thanks man! I love you!
Você falou lá no Pra quem Pedala : "Obrigado pela partilha !! :) Apesar do sotacão da eslováquia eu sou de Portugal eheheh Valeu! Abraço" . Versão em português ou pelo menos com legenda em português vai ganhar mais seguidores! Mandou bem! Abraço!
Eu nos primeiros videos fazia legenda, mas demora muito tempo fazer legenda e sincronizar tudo !! Infelizmente este ano não tenho tido tempo nem para andar de bike :(
andrextr ok, obrigado pela atencão, mas tenha em mente que teria mais seguidores daqui. Está em Portugal?
So If I understand correctly, you have to predefine correct frame type in Linkage, to get correct results... ? Otherwise it will calculate IC incorrectly, even when model visually works as it should.
+Ondrej Zvozil Exactly :)
+Ondrej Zvozil so the bikes on the list are simulated as swingarm 4bar and not as horst link (because wheel and brakes are on chain stay)
Realy cool! Never knew about this.
+Will Kirschke Thanks. I will try to talk more about this. But now you already can guess how good the braking is just by looking at any bike. Bye :)
entonces un trek session es básicamente un singlepivot con un freno flotante y el commencal supreme dh v3 es un singlepivot tambien?
Si, es correto. DH V3 es una pura single pivot con una bieleta no amortiguador (afectando solamente o leverage ratio). Salu2
andrextr También hablas Español?!!! 😮
So, if the caliper moves not much then does the rear wheel rise up when rear breaking? and if the caliper moves pretty much then the rear wheel doesn't rise up and shock is stiff even though the shock is not compressed?
+jungjoon choi Im planning a video about this, but I'm a bit busy these days, but when the caliper don't moves much it means that the braking won't affect the rear suspension, however, when you brake the rear wheel your weight shifts forward unloading the rear end and causing the rise of the suspension (you can easily test this on a parking lot...When you apply the rear brake on all Horst link bikes with an horizontal rocker arm, the shock extends). On single pivot bikes (and other designs where the caliper rotates more, or even in Motos..) the antirise is higher meaning that braking force cause the squat of rear suspension. When antirise is close to 100% this squat force is similar to rise force, so when you brake the suspension don't move and geometry don't change (you can easily see this on parking lot on a single pivot bike). Bye
So, how does this affect the past video comparing Mondraker Summum Carbon and Trek Session 9.9 2015???. Thanks in advance!
+Clefrigh Summum and Session analysis is correct (they both have a virtual pivot). All the incorrect bikes are present on the table in the beginning (and the videos for those were already deleted)
So, trek slash has an anti squat character as a single pivot bike? and anti brake squat character as a floating armed suspension?
+jungjoon choi Exactly!
thank you.
just recieved you reply thank you very much
excelente o canal, pense na legenda em português!
Obrigado José! Nos primeiros vídeos eu fazia legenda, mas demora muito tempo fazer e ultimamente não tenho tido muito tempo livre para o canal :(
do you have a website with all your bike analyses?
I have a doubt that is, How did you find the height of COG?
What type of valve does it have?
Good day... Can you help me with something? Can you tell me please, if it is 'ok' to have different suspension travel in the front & rear & if yes, what the limit may be? Also can you tell me if one can use a larger or smaller rear shock that stock? (& if yes, by how much) Thanks...
+Marvin Connell Hi, it depends on the bike but in many cases you can have a front suspension with slightly more travel than the rear suspension. You can find that information on the owner's manual of the bike. For instance, many bikes with 150mm of rear travel can handle up to 160mm of fork travel. For the rear shock, it's not recommended to change the eye-to-eye length or the stroke of the shock (because that leads to a drastic change in the geometry and in some cases the rear triangle or the wheel can hit the main frame). Bye
+andrextr What about less travel in the front than the rear? I should explain - I have a 100mm hardtail & am looking into getting a full suspension frame with 150\160mm travel... I would like to simply swap parts but same is limited & forks of equal travel are expensive... So I'm looking at alternatives... As of yesterday I'm even considering using a rear shock with less travel(eye to eye) - any thoughts on that? THANK YOU for your responses... =]
Reducing the shock length can cause the wheel or the rear triangle to hit the main frame during a bottom-out (since the shock length is smaller it means that the suspension moves further). So, it depends on the clearance of the frame, but I don't think is a good idea. Having a 100mm fork in a 160mm bike does not have any problem, but the bike will feel unbalanced... There are some 130-160mm forks that are not much expensive, such as sektor/recon silver, or the heavyweight RS Domain (you can bought one under 200$ / €). Or a second hand one. Or Suntour forks. Bye
is the instance pivot changing if I set the fork or rear shock sag differently in virtual pivot bike? and so are the results including anti squart, anti rise..?
The IC moves during rear suspension movement, and in some bikes this makes the AS and AR to change drastically during suspension travel. The front suspension travel can change a bit the IC, because the bike tilts forward, but this is a detail.
What about GT Force 2014+? It has upside down linkage. Will it affect the position of anti-rise line?
GT Force is a swingarm 4-bar (similar to single-pivot), thus, the IC is fixed on the main pivot. Given it's high position, GT Force has an higher anti-rise (around 120%). Bye
I was looking for the Commencal AM V4 vs V3, is this why you removed it?
+Prospect Visuals Yes, that's why. Sorry. However, in the case of Commencal the error almost didn't affect the results. I might re-do the video again in the future. But, with the correction, both V4 and V3 are very very similar. Almost identical. Anti-squats close to 100%, anti-rise close to 90%, and progressivity of 20% in both cases. The differences are thus visuals, geometry and probably weight / rigidity. Bye
even when anti rise is very low, rear shock works freely? not locked?
+jungjoon choi When it's zero the suspension is not affected at all by the braking forces. When it's very high, like 150% for instance, braking will compress significantly the rear suspension under rear braking, stiffening the shock and making it to rebound slower. Overall these effects are not very drastic since they are limited by the tire traction (when the tire skids you reached max effect). The shock won't fully lock out, that's only some exaggerated marketing claims. Bye
I heard somebody said ' brake jack' in which suspension is extended and locked when pulling the rear brake. what is brake jack? is this related to the rear brake squat? or is it refering to dive of fork when fornt braking?
Brake Jack is when the braking force extend the suspension. That happens in very rare cases when the IC is located behind the rear wheel. The Lawwill design is one example of that. But even in that design the brake jack is solved by mounting the brake caliper in a floating brake arm (see Rotec Lawwil for instance). For most bikes what you get is brake squat and not jack. Bye
hello. could you tell me where is the IC to my bike(merida one twenty 2015 model) becouse i dont think is the same like that last trek. thx!
+robertr32 Medira one twenty has the wheel and brakes on the chainstay, therefore it will work as a singlepivot, and the IC is on the main pivot (near the bottom bracket). Bye
+andrextr thx for your answer. i was not sure, but i suspected it was there.
+andrextr hello again. could you tell me what is the force neded to bottom out my rear shock on my merida one twenty with 20% and 25% sag at my 90 kg with gear. thank you.
the linkage x3 program calculates these IC and the anti-rise line?
+Omar Dakar Yes, this is the way that the software calculates the anti-squat and anti-rise. If you want to see those lines you have to select the option at the top left corner to show them. Bye
Which software did u use for simulation??
th-cam.com/video/Ozlu1I_BHLo/w-d-xo.html
hello, what is the program you use to analyze the bikes forces?
Linkage x3. I have a video about that
12:10
What program did you use to make this animation?
th-cam.com/video/Ozlu1I_BHLo/w-d-xo.html
@@andrextr Awesome! Thanks for the reply.
$25 Isn't bad at all for how powerful that program looks. I'm really curious how my budget build bike stacks up to these other bikes. If you ever want to make a video of an Iron Horse - Warrior 3.3, I could provide a photo and all the specs.
Very interesting video !!! Can you thalk me about the 303 yeti rail sospension system Istant Center ?... Thanks
+Sergio Rebuffo Hi. I build a picture to answer your question (see below). Keep in mind that IC moves during suspension travel. Bye
ep1.pinkbike.org/p5pb13444350/p5pb13444350.jpg
Youre born to be lecture ...
IC looks like a baloney to me. Take a new Demo for example and do a little thought experiment. Lets modify rear triangle element that holds rear axle but IC will stay the same. Lets just move rear axle is very very very close to low linkage bearing. IC would stay the same because we didnt change linkages. After modification: rear path moves practicly single pivot path of lower linkage, and has nothing to do with IC.
+maqusss Yes, moving the rear axle doesn't change the IC. However, it would change the anti-squat and also anti-rise (because for anti-squat calculation, you need the IC and the position of the rear axle also), and for anti-rise the rear wheel contact point position is also required, and by changing the rear axle you also change that. I did your experiment in Demo, and for instance, the anti-squat for a 36T x 18T droped from +35% to -65% (a reduction of 100%). The difference is anti-rise is much lower though (5%).
The closer you put the rear axle to the rear pivot the closer the bike will work as a singlepivot for the anti-squat. In the case of Trek ABP / Split-pivot, as I said in the video, you get the same anti-squat result either if you simulate it as a moving IC or as a fixed IC at the main pivot... So, it looks like baloney at first, but at the end it makes sense :) I will talk more about the IC, braking and pedaling in future videos, so I hope it will make sense to you. Bye
+andrextr thank you for explanation. Im still digint into this anti squat and anti-rise.
What i find tricky is case when IC is not fixed point. Thus its hard to see why rear wheel should rotate around IC.
Yes, I understand you. And it's not easy to visualize it, but I will try to convince you. With a IC fixed you have a perfectly circular axle path. With a moving IC, the center of rotation changes, and thus the wheel path is no longer perfectly circular. See this crazy example that I did (link below). As you can see, the wheel path changes from a vertical shape at the beginning to almost an horizontal shape at the end. That's because the center of rotation changes drastically it's position, and the wheel is almost moving horizontally at the end (the IC at the end goes to the top of the rear wheel). I'm not an engineer, but I hope this example can convince you. Bye :)
ep1.pinkbike.org/p4pb13431926/p4pb13431926.jpg
3:50
Your putting coals in the fire of suspension myth. It’s a bicycle! Look at contact patch movement of the rear wheel through travel and forces on the shock through travel. Fixed and moving pivot design just get close results with different approaches. Best tune for rear suspension? Chain guide.
C horrible a écouter achetez un micro et des court de prononciation
I would like this video but ya know.. 420