911GT3

Has anyone experienced this? 2010 997.2, OZ Superforgiattas, Pirelli Trofeo Rs, 27psi hot front, 29 rear, after 4 20 min heats, tires have rotated enough on the rims to cause tires to be so unbalanced they vibrate like crazy. I am an intermediate driver, drive fast but way under the car's limits for sure. They are slipping with acceleration, not braking, as the tire rotates (slips) clockwise with respect to the wheel.

mooty

u had race shop mount the tires?
hair spray?
does wheel inner lip got texture?

CRex

Trofeos known to do that as badly as hooters. Start your laps with high cold temps (27 all round) to minimize. They'll still do that anyways if u really drive them hard particularly the fronts.

Consider running an extra 1-2 pounds of hot pressure. Under inflated Trofeos are really frustrating to drive and break away without much warning.

mdrums

Rough up bead on your wheels and mount tire dry or with hair spray. This is common with many other tire an wheel combo's.

StatmanDesigns

It is happeneing under braking most likely... Clockwise and counterclockwise will depend on which side of the car you are looking at.

Ajjra

If my pressures are low enough I can get my Superforgiatas to slip in Hoosiers, but not drastically and not enough so that they feel out of balance...

George from MD

There's your answer. Hair Spray works great.

TRAKCAR

Rotate 180 degrees, flip tires and vibration gets less.
Even with BBS I've never been able to stop tires from rotating.

philstireservice

A good race minded tire shop would have the proper mounting compound. Not Europaste.

LVDell

And that would be Aquanet extra hold unscented.

911GT3

Can't be braking, as the direction of tire rotation is clockwise with respect to rim; so the wheel is "accelerating" faster than the tire. I would have expected them to rotate the other way due to braking, as braking forces should be much greater. What I did to remedy the situation, was to switch rears from driver's to passenger side day two, and by the end of the day they were right back where they started!

LVDell

How can you be sure which direction they are rotating? Curious how you'd (or any of us) able to tell the difference between 90 degrees of accel rotation versus 270 degrees of decel rotation? Both scenarios leave the tire at the same place.

911GT3

They way I thought about it is that is that I mark the tire at the valve stem, then check it after each heat of about 8 laps. It continues to move in the same direction, on both wheels, as the heats are completed. So, like 10 degrees each time. Then when I switched the wheels from rt to lt, it marches back to the starting point. I see what you are saying, but seems like it would be unlikely to be braking as the fronts didn't move nearly as much and they get the brunt of the braking forces. Maybe the rears were harder to mount and the dealership used a different lubricant for the rears than they did for the fronts. I didn't notice this issue on the first set of Trofeo Rs I had. BUT, I do see your point--without checking them with a more controlled test, I guess there is really no way to know for sure. You can be sure I will look at this more closely next time at the track.

StatmanDesigns

Is this really not clear that opposite sides of the car will rotate the tire in different (cw or ccw) directions, so you saying since it rotates one way versus the other is of no consequence...also the tire will rotate in the same direction relative to the wheel if it slips due to acceleration or braking. Think about accelerating first looking at passenger side rear wheel: the wheel is being turned by the axle clockwise, so if it slips the tire will move counterclockwise relative to the wheel. Think about braking: the tire is being deccelerated and the wheel is trying to spin clockwise within the tire, so the tire will move counterclockwise relative to the wheel. So you will not be able to tell the difference. That being said it is happening under braking...

almeena58

I had the same issue with Corsa system, now putting the right side tire to the left needs caution.

Corsa for example has dedicated tire for each side and it is written as well on the tire outside.