So I just recently put new tires on my factory rear wheels. I went up in size to 255/40 from the OEM tire size. The tires are brand new Continental Extreme Contact DW. They are incredibly grippy but at speeds above 65 mph the car seems to lose stability. When i change lanes even mildly quick, not fast or jerky, just smooth, the car seems to want to continue going in the direction i turn it. It's almost as if the rear end of the car kind of throws itself around whichever way I turn it. The tire pressure is correct on all 4 tires at 35 psi. I also tried running them at 32 psi, and 38 just to see if I would notice a difference and it seemed that 35 psi was the best. I once had a set of really crappy Nexxen tires in the same size and they did the same thing but I figured it was because they were poor quality tires to begin with, but now that I have good tires on the car the only conclusion I can come up with is the tire size. So for anyone who has any knowledge or experience with this or a similar situation, could the minimal difference in size cause such a dramatic change in performance?

 

New tires will have a lot more tread squirm than tires that are worn down to the tread bars. You can feel this.

Size is fine, Honda put 255/40-17s on the CR, which has the same width wheels as all AP2s.

 

I never experienced your situation with my "crappy" Nexen N3000 tires EVER! You paid over $300 for each of those GOOD tires and you still have stability issues, maybe you should start looking at something else causing your stability issues other than the tires.

 

Did you have an alignment done? If not I would check that first.

Kevin

 

I didn't have an alignment done. Could it be that going from the OEM Bridgestone that has such a rigid sidewall to a tire that has a less rigid sidewall could cause the condition? It almost feels as though when i turn a certain direction the rim settles over the sidewall to the outside and wants to stay there. It's a very uncomfortable feeling when you're on the highway and need to change lanes fast.

I forgot to mention that I still have the OEM Bridgestones up front in the OEM size.

 

bump

 

I had the similar thing happen to me when I went with Sumitomo HTRZ III from my old Star Specs. It was a bit un-nerving so I immediately sold the Sumi's and went back to Star Specs.

 

Yes, it likely also has to do with less-stiff sidewalls than OEM S02s.

If you're on the highway, first of all try to avoid situations where you "need to change lanes fast" and don't be one of those guys who has to YANK the car over for lane changes to feel sporty.

You may have to be more gentle/subtle with initial inputs at the steering wheel.

Different brand/model tires can behave quite differently. It looks like the DW is a tire that offers excellent grip, but has some squirminess that impacts precision:
http://www.tirerack.com/tires/tests/...y.jsp?ttid=120
"# What We Liked: Good road manners and exceptional dry and wet braking traction
# What We'd Improve: Steering response and a little more precise dry handling"

"The Continental ExtremeContact DW followed and displayed responsive steering once the vehicle was into the corner. But when going straight down the expressway, this tire was easily nudged off course by moderate crosswinds or the whoosh of a passing semi, requiring frequent but small steering corrections to maintain a straight track down the road."

 

You can also have the differences of the two different tires. Front S02 that are half worn and new Contis on the rear. Some tires just don't play well together. New Contis on the front would solve most of the issues I believe.

 

what if i just went to dunlop star specs in 245?