This to me is just plain odd. I just had new tires put on in the rear only. Fronts still good. There BF KDW. Went from a 275 to a 285. Same tire brand as before, just a little wider.

When I start to reach speeds of 100 and up, the car seems to want to drift from side to side. Sort of like it's floating. Never had this before. Always was a firm still ride. What could cause this? This is the only thing I've changed since. The only thing I notice is when temps are cool, it seems ok. But when temps are high outside, this is when it happens. Might have something to do with it or not.

 

How many miles are on the tires?
New tires are slippery.

 

i had the same problem......the place i got my tires mounted had the pressure at 50 on the rears

 

As someone else mentions, new tires have a protective coating that makes them very slippery. You notice this most when replacing your rears. The fix is easy (or automatic if you do nothing at all since it corrects itself within a few days of driving). For a fast fix, drive up to 50 mph and pull the steering wheel left and right briskly.

Also, make sure you are running the correct tire pressure (34-36 psi).

--Spike

 

245/275 is where I have it. When I had 225 up front, I was having the same problems. if you went 285 in back, then maybe a 255 up front will fix your issue.

 

Thanks for the info guys. There's less than hundred miles on them (casual driving). The tire pressure is good. I'm always on top of that. That must be it, new tires slippery due to coating. I'll also do some brisky driving to help break in. And when my tires in the front go bad, I'm going with 255 in the front.