Wheel Alignment spec

Otis, wheel alignment specs for your car should be whatever causes the machine to handle right for you. Factory alignment values from the U.S or Europe will likely not do this with 16" & 17" tires. This is often done for appearance, not handing. With the sizes indicated, the car will probably understeer badly due to the rear tires being wildly overwidth compared to the fronts. Those 335-35s are an inch wider than what the GR-4 racers used at LeMans on 15" x 14" wheels.... They also are 2" smaller in OD than stock, so the effect on your gearing is something near 4.44:1 rather than stck 4/22:1, so your mileage will suffer & top end will be lower. Your speedo won't read true and acceleration will be enhanced.

To correct most of this, either narrow the rears to 295s or increase the fronts to 245 in order to rebalance the car. Twice the maximum stock caster of -2.6 degrees will help, as will a 1"OD rear swaybar (stock is 3/4"), hollow if possible, with sphereball ends. Less than 50-profile fronts probably will only need 1/8" of toe-in and with a little fiddling, you may find it needs only half that amount. When we redesign Dallara's geometry with big wheels & tires, experimentation must be done to optimize. Good luck.

+1 on BossWrench's comments.

IN ADDITION I have found that FOR ME the old specs do not work with the new tires well.

For instance, I have had to dial in negative camber in order to get the wear pattern even across the tread. The traction tends to agree with the wear patterns in my experience.

Instead of using the -1/2 to -3/4 degree camber in several cases I would up with -1 to -1.5. That is quite a change.

This is really reminding me of my autocross days when the car was always being screwed with on the alignment rack.


My Taurus SHO just to set the front tread flat wound up at -2.5.

If you look at the car from the front it looks like an old Mustang with busted upper ball joints BUT that's where the tread rides flat.

Thanks guys, I hope its not too much experimentation. I know there are still quite a few on here running those or similar tire combos with the Pilot Sports. Any one else willing to share their alignment specs?

Before I wrecked a ball joint the car handled fairly well for the driving I do and tire wear was very good, so hopefully I can get back to that.

Bosswrench- My speedo may have been played with already since I know the last time I was on a chassis dyno the speedo was reading dead on, however I am guessing discrepancy would show during the faster runs.