I'm running about .5 degrees negative in the fronts (to help tire wear,
thanks for the suggestion Bill!). Rears are zero degrees camber, detroit
locker diff (basically acts like it's welded in the corner under power as I
understand it). I got 5 1/2 sessions at Blackhawk then rotated the still
decent fronts to the pretty beat up rears, and maybe 4 at Grattan before I
had to start replacing tires because I was worn to the point that at least
one of the tire grooves were essentially gone. By the end of the weekend
(6 sessions) I had replaced 3 of the 4 tires with almost worn out but still
usable tires. Probably would have replaced the 4th but wanted to keep
Snook going.
I run 26 psi front / 24 psi rear (plain old air). I bumped the rear
pressure up a psi from 23 to tame some of the oversteer in an attempt to
get more tire life. Rears wear out the inside edge first. The car has
some amount of oversteer, but I tried to not hang it out too far. I'm
giving up on Hoosiers and am going to start trying other
brands. Unfortunately, nothing is really available in 60 series so I'm
forced to go to 50 series tires (or Dunlops and add 2 to 4 seconds a lap to
my times).
While I don't do the math to know what I spend a race, I'm spending over
$400 in tires alone per race weekend.
Of course, Jack knew all of this, but the rest of you didn't...
- Tony
At 11:27 AM 8/24/2005, Bill Babcock wrote:
>It would be useful to know the suspension setting for the cars that are
>gobbling tires. Also, what do you call a "worn out" tire. Is it worn out
>when you start seeing your lap times come down a bit, or are you driving
>them to the cords?
>
>I see a lot of cars on bias ply tires that are running a degree or more of
>camber, like it's some kind of rule that camber=good. If you have added
>camber by shortening the upper arm, then you have a lot of camber gain, so
>even if you set it at zero degrees, as your suspension compresses you get
>more.
>
>I'm running Peyote with zero to .5 degrees of camber, zero toe, and whatever
>caster that a TR6 lower trunnion gives (I think it's 3 degrees). I have
>about 2 degrees of camber gain at full suspension travel (compression). The
>Ackerman point is about five inches before the rear axle.
>
>Using Hoosier vintage TDs 5.50 X 15 front and rear, about 22 pounds in the
>front, 24 in the rear, nitrogen.
>
>My tires give even temps across the face and show no sliding marks--the wear
>is even across the tire. I gain about 1 second with new tires after one heat
>cycle, lose that back after ten or so cycles. After ten cycles there is no
>further degradation of lap times. I run tires to 30 or 40 heat cycles or
>more. So far this season I've bought one set of Hoosiers to replace the ones
>I flat spotted when I lost my steering. And I bought one set of Dunlops to
>run Monterey.
>
>I'm going to be trying the DOT Hoosiers at the CRC. I'll let you know what I
>think of them. They are radials, so I'll need to play with camber.
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