My AP2 with stock rims, I wore out my Kuhmo Victoracers and switched to Hoosiers.

I now run 225/45-17 and 245/40-17 and I immediately noticed a torque steer on both accel and decel, just by applying/backing off the gas. Tire pressures are set within 0.3 psi or better, and I have changed the diff oil (Mobil 1 75/90).

I never had this with my Khumo Victoracers 245/45-17 and 275/40-17.

Note: I dropped down in size due to rubbing in the front. The rubbing was minimal until I switched to Koni Sports. and the rub was bad when I hit a bump. No rubbing in autocross! It wore thru the plastic liner at the top outer on both sides! I kept the stock ride height. Konis are much softer in bump!

I do not notice the torque steer at Autox, just on the street. Definitely still there after 2 events! First noticed when tires were new! Tire pressure = 38 psi (recommended cold).

 

The "recommended" tire pressure for an S2000 is 32 psi. 38 is a far cry from this. Who "recommended" 38?

 

38psi ? Someone needs a smack in the noggin. Even driving in very cold temps, your tires will heat up and increase the psi. Drop those things down to 32psi... I like 33 myself but to each his own.

 

Are you absolutely sure?
Here is another thread and another example of similar symptoms from an owner who was confident not only ONCE that his tire pressures were good, but posted a SECOND time that he couldn't imagine that his pressures could be NOT good and posted a THIRD time to repeat that his tire pressures are fine, only to post for a FORTH time that indeed, he had a leak since his pressure check (that he was SO sure of) and one of his tires were at a ridiculously LOW pressure.

https://www.s2ki.com/forums/index.ph...opic=342383&st

All I can say is .................................... DOH!!!

 

I keep a tire psi guage in the car with me, and check every 2 weeks 4 week... (depending on how good my memory is). I'd recommend you do the same.

 

Hoosiers have a very stiff sidewall so the tires will follow crowns/cracks etc on the street. It normally is not an issue since almost no one drives with Hoosiers on the street. My guess is that this is the problem.

Off topic but how does the grip of the smaller 225/245 Hoosiers compare with the larger 245/275 Victoracers?

 

^^^ I agree. Hoosiers will find and follow any little crack or irregularity in the road. I found my car to be a real handful the few times I've run the Hoosiers on the street.

 

Thanks for the responses, mostly...'head smacker' has not done much competiton driving where one can adjust tires pressures for optium traction.

Tire Rack includes a Hoosier Racing tire brochure, that recommends 32 to 37 psi cold,and 42 to 46+ psi hot. After a autoX run, I use my infrared tempurature gage to check the temperature gradient across the tire in 3 spots, and adjust presure to get even distribution. Of course that depends somewhat on camber. Ideal 'Hoosier' temperatures are 180 to 200 F, but I only get about 120 (knowing surface temp is lower than the better temp probes that pierce the rubber).

Tires were set only 1/2 hour before driving,and maintain pressure a full week later. There is no indication of any tire leaks. This occurred on 2 occasions, both with tire pressures reset. Note: I adjust my presures down to 42 psi on each run, after they heat up. As I get more runs, I will try various pressures. I ran 32F/33R on the Kuhmos. Note the fronts cannot use the higher presure due to the 7 in width, while the rears can, as shown by temperatures. The RE050 I ran at California Speedway, and started high, but worked my way down to (I forget-it is is in my notebook) 34 psi, which others considered high, except that it worked.

Yes the Hoosiers are a little dicy on the street, maybe slightly worse than the Victoracers. Only I distinquish the rain grove darting from the on/off throttle steer.

The Hoosiers have much better traction that the Victoracers. I found that other S2000 running the smaller Victoracers had similar times, so my conclusioin was the wider tires were no advantage, given that they rubbed, and they raised the overall rpm/speed ratio which decreased accel but gave higher mph in 2nd gear.

The biggest Hoosier advantage is that the Victoracer are slippery and unpredictable on the first cold run. Very bad when you only get 3 runs. But I knew the Victoracers were old technology, but otherwise well respected. I got a 120 runs on them, until I wore the left front down to the metal while at a Evolution school. Oh well, they got me home. On a 60 sec course, I think the A3S05 give maybe 1 sec advantage over the Victoracers. I hope they are similar to the Kuhmo 710, but they only have the larger size currently.

I am learning that 3rd gear shifts are required, if only for a second or 2.

I also found that I had 2 differnent batch numbers on the rear tires, and sent that info to 'Jim@tirerack.com' but have not heard back. Next I will measure the circumference in 3 spots on each tire with the pressure reset.

 

Yes, Hoosiers make very bad street tires. I'll add that both my car (bald Sumitomo HTRZ) and my wife's E46 (bald Yokos) are experiencing very bad torque steer, horrible in fact. Both dart all over the place. I chalk it up to finished tires and bad roads. I just had an alignment done on mine and I'm using factory toe settings so I know it's not that.

 

I measured my tires and confirmed there is a size diference of 0.215 inch diameter.

I also got a response from Jim@tirerack, who asked about the tire measurments.

I also remeasured after adding 10 psi, but saw only a neglible increase in size. That proves it could not be a tire pressure issue.

One tire is 823 rev/mile, and the other is 830. Now I wonder how bad that is for the Torsen LSD? javascript:emoticon('')
smilie I am sure tire sizes are never exactly the same size, but this was quite noticeable while drivng.

Note: I measured the circumference in 3 spots on both tires, then converted to diameters.