acorradi87

Today I had the stock REAR tires (Continental SportContact2) replaced with Bridgestone Potenza RE960s. I drove out of the shop and everything was fine until I got on the freeway. At 70mph I changed lanes and it felt as though there was a slight delay from the time I turned the steering wheel to when it actually went the direction I wanted the car to go. So I was driving in one lane and rather slightly turned the wheel from side to side and the car felt slightly unstable... it seemed like before I got these new tires my car was very precise in where I wanted it to go and now it just seems a little softer and less precise.

I'm sure there's some term for what I'm describing and being that I'm an auto enthusiast I'm ashamed I don't know what it is. If the front tires had been changed as well I can understand that maybe something like this would be felt but since it was just the rear tires I'm confused. I know that the new tires are a few pounds heavier so the weight discrepancy between the front and rear is now greater but I don't know exactly what effect increased unsprung weight in the rear has on handling.

Generally it's not a huge issue and if it's the price to pay for an increased treadwear rating, so be it. Any thoughts would be appreciated.

Thanks!

Munich77

Could the difference in performance also be due to having different brands of tires on the front and rear... something which is generally not recommended. I am guessing that the tires have different properties.

kscarrol

And recall that tires take a couple of hundred miles to really be broken in. Give them some time...

Allen

What you are experiencing is normal. I'm not sure what the "official" term for it is...but I call it "tread squirm". Your old tires had very little tread height...the new tires have lots of tread height. Your car isn't as precise and has more squirm on higher tread...ever ride on slicks...very precise handling.

Imagine it like this...I'm standing on a 2x2 ft. steel platform which is supported by rubber columns (like tire tread) say about .25 inches tall. Now I try to sway back & forth as I stand there. I will move/lean/sway a little bit I guess. Now suppose those rubber columns were 2 inches tall...and I try to sway. I will move/lean/sway a whole lot more than before...right? That's the difference in having no tread and new tread. I hope this makes some sense at all. BTW... the new tires with all that tread will give you a more smoother ride as the the tread provides a cushion...as opposed to no tread.

South Pasadena

As already mentioned, this is normal new tire behavior. Before you know it your car's handling will again put a smile on your face.

5-string

I just bought some new tires recently and noticed this exact same unstable behavior. Now I'm waiting for things to start settling in ....