I know they're asymmetrical in nature and can go on either side of the car as long as the "OUTSIDE" marking is on the outside. But...is there any harm in reversing rotation on tires that have been running on one side for a long time? I had my wheels off last week, cleaning barrels and my passenger side rear was wearing more on the inside (as they do), so I flipped all the tires side to side. (I have new tires and wheels coming, but it will be a month or so) Now I'm getting a little vibration at 95 mph and up, like I lost a wheel weight. Would flipping the wheels do this?? I'm not running spacers or anything that would cause the out of round.

 

What you experienced is what I also experienced.

Though the rears can be rotated (and of course, the fronts), I think we are supposed to rotate them frequently to ensure that minute wear will always even. I rotated mine after 10K+ miles and the car handled differently. I quickly rotated them back and the car handled normally.


My guess is that had I done a diligent rotation every 5K miles, I would not have experienced the abnormal car handling.


I have not been doing rotation since then since my wear between the left and the right are almost non-significant.

p.s.,
My local Costco now carries the PSS. A little cheaper than Tirerack.
I am just waiting for the wires to come out of rears; I'll then have them install the ones I ordered which they are keeping for 3 weeks.

 

Thanks! I'll swap them back and see! I just wanted to make sure I wasn't doing anything unsafe?

 

Just so I understand this, you actually take each tire off each wheel, and then remount the tires back onto the opposite wheel?

 

Take the rear tire/wheel (both) from the left and mount on the right rear.. And vice versa. Much like changing a flat tire with a spare tire.

Do same on the front.

You do not need to dismount the tire from the wheel.

Hope this is clear.


Note: my comment are for the Michelin Pss ps2. Some tires CANNOT be rotated like the unidirectionals.

 

I didn't know this about the PSS PS2. Thanks.

 

If you're getting uneven wear on one side then you need an alignment. Something is off kilter and causing this. Unless you throttle steering out of left turns predominantly.
Getting uneven wear on the inside in the rear tires means you're not cornering aggressively enough.

 

Actually, it has always been recommended that a little negative camber would be good on Porsches --- at least by the various mechanics that I have used and for all of the various Pcars I have owned.

My inner sides of my tires always wear down quicker than the outside. It's the price I pay (or should I say the price we pay).

It's a matter of balance between fun factor and cost; the more neg camber you have, the more fun the car but at the expense of the inside wearing down a lot more than the outside.

 

Thanks for the comments...again just to clarify...not remounting any tires, just taking the tire and wheel off and switching sides. This will run tires in the opposite direction they've been running the last umpteen thousand miles. These tires are not directional...but do have an OUTSIDE marked. I thought I had read once that it can cause some issues if they're not flipped regularly.

I have a new set of tires and wheel on the way, just thought I would flip the tires around for the next month until my new ones get here. For the record the driver side rear was also worn on the inside. As mentioned, it's normal based on how your camber is set. I am lowering the car on H&R's when the new shoes get here and will do an alignment then and see where it's at.

 

But the inside will still be the inside, just on the other inside. It'll turn the opposite direction but I can't see how this helps anything.

 

1. If there's a small difference in your alignment, rotation will help "even" out the wear and tear to the two tires.

2. Streets and fwy lanes are never super flat to promote even wear (ex., the fast lane slants to the left for water drainage causing one tire to work harder. Again, rotation will help with this.

3. Due to traffic, I often do a "circle path" from home to work and back to home. Again, rotation helps.

Hope the few examples above help.

 

Forget where I read this but it is generally not a good idea to reverse the rotation of a tire even if the tire is not a uni-directional tire.

The passenger side rear tire -- since you are in the UK I believe this refers to the left hand rear tire -- is wearing because I suspect you are a bit aggressive when taking a left hand corner.

During a turn the inside rear tire is lightly loaded and will spin if the throttle is used too heavily. (LSD can alleviate this but it is an expensive option to have fitted.)

(Here in the USA the right rear tire wears faster since most turns and the sharper turns are to the right.)

If one is moderately reasonable with the throttle the rear tires should wear evenly enough there will be no real noticeable difference in wear.

 

You and me both, brother...

 

Take the car to the track every now and again drive it hard and you will experience more even wear. Tthey are setup with negative camber for better grip on the corners when is needed.

 

Virtually all of the tires made for our cars have a rotation direction designed into the tread pattern. Look at the sidewall and you will likely find a rotation direction arrow. Do not run these tires backwards, especially if you take your car out in the rain since the treads will no longer clear water correctly and your odds of hydroplaning are increased. Our tires are already very wide and more likely to hydroplane, there's no need to help that phenomena more.

As OP originally mentioned, you could attempt to dismount/remount the tires from side-to-side, but again, most of our tires are asymmetrical and moving the outside edge to the inside adversely affects cornering performance, the outer shoulders are designed to be on the outside.

I just wouldn't do this, I don't see any benefit of doing so and see at least two known negatives outside of the old question as to whether the rotation direction of radials should be changed.