Guys, I need your help. First, a little background. My daughter was backing my S2000 out of the garage and scuffed the right rear sidewall. It was damaged enough that it went flat about three hours later. The tire was replaced with an identical tire (Dunlop Direzza). The damaged tire had approx. 8000kms on it and both rears were in decent shape.

The problem is now the handling is darty. If I'm going down the road and accelerate the car wants to go left and when I lift off the gas the car wants to go right. If I coast, I can let go of the wheel and the car will track straight. Before the tire was replaced the handling was spot on.

Any suggestions?

2000 S2000
Silverstone
OEM 16" wheels
48,800 kms

 

Check the tire pressures to start, the S2000 is sensitive to pressure differences.

 

How many miles are on the older of the 2 tires? I would suggest replacing both unless the older one has very low miles on it. Save the one that still has some life as a spare in case.

 

I second this. You're always better off to replace at least two tires at a time for safety reasons.

I wonder if the alignment could have been thrown off though?

 

You can damage the rear differential if the rear tires aren't the same diameter which is another reason to replace both at the same time. 8k miles doesn't really tell us the tread depth remaining which would be the most accurate way to measure. It could look nearly new or have less than 50% of the useable tread left depending on your driving habits.

 

Rears definitely need to be replaced in pairs or you will get the exact behavior you are describing. Essentially what is happening is the limited-slip differential is reacting to the different wheel speeds and routing torque to the larger tire. I'm willing to bet your new tire is on the right side of the car?

 

The new tire is on the right side. The tread on the left one, however, is still pretty good, though I will measure it. The tire pressures, though, were off. The left one was 30 and the right was 38. I corrected it and when it finally stopped raining, I tested the car. Huge improvement.
I was out of town when the tire was damaged and my daughter had it replaced. That's what I get for assuming it was inflated correctly at the shop.

 

OP states 8K km though the statement above is still correct in that mileage doesn't necessarily indicate tread depth.

 

Enh that's more than enough miles that I would replace both. It it were under 1000 I think you would be safe but knowing how the S goes through rear tires I would definitely replace both.

 

Its recommended that you replace them in pair. They should be identical; same company, size, load index...
Anyways, it is not necessary to replace both, but is highly recommended for best performance.

Check the tread on the tires.
If the tread is worn on the outside on both tires, this is probably related to positive camber; top of tire out.
If the tread is worn on the inside on both tires, this is probably related to negative camber; top of tire in.

It is possible that both wore on the outside (due to positive camber) and when you replaced one of them, the car
had the tendency to pull to the side with the most positive camber.

Thats one of the basics of an alignment: a car will pull the the side with the most positive camber........ unless caster
or toe is an issue.

Take your car and get an alignment. Its may be expensive but it will save tire wear and who knows, an accident!?

Thats my 2 cents. lol

http://auto.howstuffworks.com/under-...-realigned.htm