apathic

I replaced the rear tires on my '97 986 yesterday - forgot what brand they were (some no name cheap tires, the drivers side was shaped like an egg the way it rolled) with Kumho Ecsta ASX. I also went from 255/45/17 back to the original 255/40/17 (so now my speedo is off by a little bit more now - no biggie.) Left the shop, pulled over and put 36psi of air pressure in, and I swear - the car feels so much more "loose" in the rear. It actually feels like the rear sway bar was unhooked or something. Am I running to much air pressure, anyone got any experience with this tire in the back? (I have Goodyear Eagles of some sort in the front, they are find so I didn't replace them yet)

VGM911

Two rules to remember:

1) When a tire is made and released from the mold, it may be a bit "greasy." This means that you should drive cautiously for about 50 miles to "break-in" the tires. Once the greasy substance wears off, your traction will increase.

2) Always try to match tire brands/models at all four corners so that your handling characteristics will be well-matched and predictable.

Good luck.

No HTwo O

^I agree with VGM911.

I just put new Kumhos on the rear (they do match the fronts) and the paperwork I got with the tires said "500 miles". FYI.

Did they put them on in the right direction of travel?

brad@tirerack.com

I agree they need to be scrubbed in to get the mold release out of. Also keep in mind that new tires also have more tread depth, and as a result "squirm" than the ones that came off. You may be feeling that lateral movement also.

The ASX is also an all season tire. Are you matching it to another pair of all seasons, or a pair of summer tires? The Eagle is a performance "family", not a model so I can't tell. By now you are finding out these cars don't really appreciate mixed tires.

apathic

Thanks for the advice, I do hope it is just tire grease (for lack of a better term.) The tires are in the right direction, that was the first thing I checked. Hopefully this is all in my "head" - I wasn't pushing the car at all.

Type_LT

apathic, they should be fine like everyone else said.

I do remember being disappointed once when I changed from yokohama high performance summer tires to some all season style tires. Huge difference in sidewall stiffness between the two. The yokohamas would bite quickly with little steering input whereas the all-seasons were a bit sloppy on initial turn in. Thats the all-season tradeoff.

Look at it this way, when it's <50F outside you'll still have traction

racer

How would your speedo be off if you went back to stock size?

What type of tires are on the front? How many miles on them? x 2, or 3 or whatever about the mold release/squirmyness. But if you've mixed and matched tires, it may not be just a temporary issue.