Date: Mon, 21 Jun 1999 23:35:23 EDT
From: Mtnman3620@aol.com
I know that since the g-forces have much better turn in they don't need as
much toe out as the old R1s. Well, how much do they need(in a general,
understeering car)? 0"? 1/8"? 1/16"? TIA for the input.
Hi Daniel:
The BFG recomendations say the tires will turn in as good as the old tires
with less toe out, but I don't think this means to run no toe out. Just
experiment and don't just keep doing what has been done in the past, the
tires do respond quite different.
Our cars are probably very different, but many things cross over when it
comes to steady handling and even turn in with respect to tires. I never did
try my old setup with the G-Force tires, but the changes I made were based on
the BFG care and feeding page I downloaded from The Tire Rack web page. I
went to softer sway bars, and adjusted my camber and caster to maintain at
least 1 degree negative while cornering. I run close to 2 degrees static, and
the caster in the front gives me a bit more than 3 degrees at a 20 degree
turn angle on the outside tire. I set my toe while testing on street tires. I
set my toe so that at a 20 degree turn angle the tires roll with no scrub.
This required a ful 1/4 inch toe out on my car. This sounds like alot, but
really is not too bad. I drive it like that on the street to and from events,
even over 100 miles has not been a problem.
A 20 degree turn angle is about the most I ever use on an autocross event,
that is the steering wheel turned about 1 full turn. I plotted where the axis
of each front tire would intersect the rear tire axis, then adjusted total
toe til they hit the same point. This ended up to be 1/4 inch at the rim.
With this setup, I put on the G-Force tires and the turn in has been
incredible. My tire wear rate has also been stellar. The car has run close to
100 runs and all four tires still look fine for many events to come. I am not
sure how the big events tech the tires, but the gauge holes in the tire are
still about 1/8 inch deep, but the main grooves are getting low on one tire.
It is a rear, and I think it is from tire spin on the starts. From this I
think the tires will be good for about 150 runs, about double what I got on
the Hoosiers I ran last year.
Gary M.
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