Ok, could someone please explain to me exactly what causes brake jack/squat (in terms of vectors etc)? And how does a floating brake (optimised of course) solve this problem? I'd appreciate the use of a singlepivot as an example because I don't understand moving ICs etc and what effects that has (what defines the Instant Centre anyway?)
My theory at the moment is this:
When the rear brake is applied when the bike is moving, the contact patch at the bottom of the wheel tries to move backwards in relation to the bike (ie tries to maximise the horizontal distance between the contact patch and the pivot). Given that the contact patch shifts relative forwards on the wheel as the wheel moves upwards, if the pivot is fairly low, it won't make much difference. However if the pivot is high (BB7 etc), the distance can increase considerably more, making the wheel try to move upwards, which breaks traction, skids, and feels like it's locked out.
Is that right (or close to)? I'm at a loss as to understand how a floating brake changes things...
Thanks
My theory at the moment is this:
When the rear brake is applied when the bike is moving, the contact patch at the bottom of the wheel tries to move backwards in relation to the bike (ie tries to maximise the horizontal distance between the contact patch and the pivot). Given that the contact patch shifts relative forwards on the wheel as the wheel moves upwards, if the pivot is fairly low, it won't make much difference. However if the pivot is high (BB7 etc), the distance can increase considerably more, making the wheel try to move upwards, which breaks traction, skids, and feels like it's locked out.
Is that right (or close to)? I'm at a loss as to understand how a floating brake changes things...
Thanks