Re: Brake reg. setting on rally cars

[Brett Corneliusen <afmoa@skypoint.com>]

>I have a question for listers familiar with rallies, autocrosses etc. I
>was watching TV coverage of some local rallies and noticed that all cars
>(no matter if FWD or AWD) would lock their rear brakes first. I
>understand that on street cars the brake pressure regulator is adjusted
>to make front wheels lock first, while preventing rears from locking. Is
>it set up differenly on rally cars or do the drivers use some technique
>to make the rears lock first? What's the purpose of doing this?
>
>Aleksander Mierzwa
>Warsaw, Poland
>mailto:alex@matrix.com.pl
>87 Audi 5000CS turbo (mine)
>88 Renault Medallion wagon (mom's)
>91 mountain bike (just in case both cars broke at the same time :-)

Al-

Not all rallydrivers have the brakes set to the rear.  Some use the
Emergency Brake for hairpin turns.  I personally would like to have a
little more rear bias in my VW rallycar, but can't afford the mods for
that yet...

By having lots of rear brake bias the car wants to swap ends during
braking.  This is great for twisty stages, but not the hot setup for
long high speed sections.  Another good method for braking is engine
braking- just lifting your foot off the gas but leaving the car in gear
will slow you down, or even downshifting while off the gas.  By using
engine braking you can still steer the car.  If you lock up your brakes
the tires are not rotating and you lose directional control.

Carl Merril in the US runs an Escort Cosworth with LOTS of rear brake
bias.  I have seen his car come into a finish control with stone cold
front disks and his rear disks glowing with flaming pads!
-- 
Brett Corneliusen		mailto:afmoa@skypoint.com
VW/Audi owner			accountible for my own actions
Cendiv ProRally Page----->	http://www.skypoint.com/~afmoa