[Lelandjt]

The axle path, chain growth, leverage curve program you guys found me was great. Now I'm curious if anyone has figured the extension/compression force that a brake exerts on different frames.

Edit: Sorry, only talking about the rear brake and suspension.

 

[fluider]

If you mean the rear brake effecting the rear suspension, whether suspension compresses or exerts under rear braking which is also called anti-rise, then you can watch this property in Linkage as well. You only have to turn on the 'Anti-squat values' checkbox in one of the dialogs and a2 is the value you're looking for. a1 is standard anti-squat, if I'm not wrong.
BUT, since even Gergely (the head programmer) cannot provide new functionalities and support for free forever, the program doesn't work correctly in special cases like SplitPivot, floating brake etc. So better be cautious.

 

[Vrock]

Split Pivot Works Fine, it's just a FSR frame with the rear pivot at the axle. If you use the 4-Bar template the program put the caliper in the chainstays, but that's not the program fault. Floating Bakes doesn't work very well, but you can draw it, export to dxf and finish the calculation with CAD Program in 5 minutes...

 

[fluider]

You're right, but then user must keep 2 files of 1 split-pivot frame, one for anti-squat (single pivot template) and 2nd for anti-rise (fsr template). Floating brake can also be done this way, except for Rotec bike which has special floating brake.

 

[Steve M]

You're right, but then user must keep 2 files of 1 split-pivot frame, one for anti-squat (single pivot template) and 2nd for anti-rise (fsr template). Floating brake can also be done this way, except for Rotec bike which has special floating brake.

Should be able to use the FSR template for both no? The singlepivot template won't actually show different anti-squat to the FSR one - the line from axle to IC will always pass through the main pivot anyway if the "horst" pivot is coaxial with the rear axle.

 

[fluider]

You're right Socket, I didn't realize that possibility.

 

[Lelandjt]

I played around with it and didn't accomplish much (like I said, I suck at computers). What I'm wondering is how the Scott Genius LT reacts to braking. You can use the Yeti ASR7 from their web library since the frames are identical. Anyone want to run it and tell me what you find?

 

[fluider]

Sooo, the Yeti ASR7 2009 model that I found in web lib and its anti-rise (the red curve) graph looks like this. It starts at 120%, with cca 116% at SAG, gently falls to 102% in the end. This shall mean that under rear braking the rear suspension will have very very weak tendency to compress. The percentage value describes ratio of suspension reaction force to acceleration force. So if it's 100% they are both equal in magnitude but in opposite direction. 116%, or 16% over 100%, is too small difference to be felt.
But, these values depend on actual position of CoG and the CoG in Linkage is just an estimated position. So, by moving it up little bit the resulting anti-rise value falls little bit, so you may end up with cca 100% at SAG, I don't know.

If I described something wrongly, I hope at least Socket is gonna correct me.