Originally posted by Rara:

but seriously, just pointing out potential issues w/ fixed calipers; they aren't "perfect" is all I'm getting at.

And fwiw, under hard cornering, most any stock wheel bearing (unless it was way overdesigned to start with) will allow some knockback on a fixed caliper. I know I've seen a number of Mustangs that get the occasional extra travel after a corner from knockback.




Just to expand a bit.

Its true that fixed calipers are more sensitive to knuckle/bearing flex, making them more succeptable to knockback. However, that doesn't mean every fixed caliper will exhibit it. When a caliper is placed at either 3 or 9 o'clock positions, knockback due to deflection is rarely an issue. This is the problem with the mustangs, the caliper is located high on the knuckle (1~11 o'clock). When the horribly underdesigned knuckle and bearing of the mustang (SN95, not S197) loads up and bends, the caliper is sohigh on the disc, where the deflection is quite a bit.

Caliper knockback is simply a symptom of poor bearing and/or knuckle stiffness. Its not the caliper that is the problem...its the corner assembly. In addition, this can be compensated for by tuning the piston rollback/knockback characteristics of the outboard pistons differently from the inboard pistons.

Aside from knockback sensitivity, the only other issue facing fixed calipers is wheel packaging due to the outboard caliper half. Aside from that, it is simply a better design.

Cheers,
Todd

Very few of life's problems can not be solved with the reasonable application of more horsepower!