Re: Racing environment brake performance (viasevenvai)
your trap terminal velocity is 100mph plus/minus and when you are hard on brakes, front end walks side-to-side felt through steering wheel... no abs intervention
at moderate to high road speeds chassis will slew laterally when:
(1) rotors may be warped from overheating/rapid cooling (thermal warping) and/or non-uniformly/incorrectly/excessively tightened wheel bolts (mechanical warping)
correctly retighten in sequence with accurate torque wrench all wheel bolts - all threads should be clean & dry - NO grease or anti-seize on threads
just before making run, preheat rotors - suddenly going hard on brakes from higher road speed may cause transient thermal warping, which may self resolve or may not self resolve
(2) one or both front tires have belt run-out
radial street tires or bias drag slicks??? big difference
first confirm "cold" tire pressure, second:
rotate tires left rear to left front and right rear to right front
also shave all tires to uniform rolling diameter
(3) your drive factory fitted floating brake calipers - if one or more bind and will not immediately self-align to rotor when brakes applied - chassis slewing can occur
(4) you have used excessive amount of tire grip solvent on tread just prior to making run - by end of run tread compound rehardened non-uniformly left to right tire resulting in slight traction difference
long story short - rotate tires back to front & preheat brakes just before run...
when this occurs on circuit car, driver(s) & mechanic foreman usually exchange sharp words...
Modified by iamnobody1 at 12:37 AM 10-18-2008
your trap terminal velocity is 100mph plus/minus and when you are hard on brakes, front end walks side-to-side felt through steering wheel... no abs intervention
at moderate to high road speeds chassis will slew laterally when:
(1) rotors may be warped from overheating/rapid cooling (thermal warping) and/or non-uniformly/incorrectly/excessively tightened wheel bolts (mechanical warping)
correctly retighten in sequence with accurate torque wrench all wheel bolts - all threads should be clean & dry - NO grease or anti-seize on threads
just before making run, preheat rotors - suddenly going hard on brakes from higher road speed may cause transient thermal warping, which may self resolve or may not self resolve
(2) one or both front tires have belt run-out
radial street tires or bias drag slicks??? big difference
first confirm "cold" tire pressure, second:
rotate tires left rear to left front and right rear to right front
also shave all tires to uniform rolling diameter
(3) your drive factory fitted floating brake calipers - if one or more bind and will not immediately self-align to rotor when brakes applied - chassis slewing can occur
(4) you have used excessive amount of tire grip solvent on tread just prior to making run - by end of run tread compound rehardened non-uniformly left to right tire resulting in slight traction difference
long story short - rotate tires back to front & preheat brakes just before run...
when this occurs on circuit car, driver(s) & mechanic foreman usually exchange sharp words...
Modified by iamnobody1 at 12:37 AM 10-18-2008