Tires - to rotate or not to rotate

[Dirichlet]

I have Michelin PS2's on my car, and the front set are just about cooked (at least around the outside edges)... The rear seem to be fine. I'm wondering if I should:
a.) buy two new tires for the front
b.) buy two new tires, put the rears on the front, and the new on the rear
c.) buy no tires and simply rotate front to back
d.) buy four new tires (financially not desirable)

I autox and attend driver's schools - any input greatly appreciated.

[jkuper]

Flip them on the rim, i.e. put the outside edge on the inside. I don't know the specifics of PS2 (directional, inside/outside, etc) so look that up.

I doubt you could rotate front to rear, don't you have different sizes?

[Dirichlet]

Flip them on the rim, i.e. put the outside edge on the inside. I don't know the specifics of PS2 (directional, inside/outside, etc) so look that up.

I doubt you could rotate front to rear, don't you have different sizes?

Can't flip 'em - inside/outside specific. Front and rear are same size - aftermarket 18x8...

[SMOODY]

If they are all the same size, which I think your's are, then you should be able to rotate front to rear. That should get you through the autocross this weekend.

If the front tires are truly shot, I would get new ones for the front and put the two best of the old tires on the rear.

[hoyabmw]

b.) buy two new tires, put the rears on the front, and the new on the rear

I autox and attend driver's schools - any input greatly appreciated.

Always put the tires with the best tread in the rear. So option b is probably your best one if the fronts are truly done. But if you're autoxing this weekend, I'd wait until after the event to buy new tires. Unless you're showing cords, in which case you'll fail tech.

Kevin

[daddeu]

The ONLY thing that makes a tire directional (asymetric), assuming its DOT street legal, is the tread design. Admitedly, most tires have what is called a "beauty side" which is on the outside of an asymetric tire. However, that does not affect performance in any way. A past exception was Goodyear's Comp T/A R1 that had a stiffer side-wall construction on the outside. Even those tires could be flipped but for predictable handling you needed to flip all four.
For the front tires, may I suggest: Flip them to put the good rubber on the outside. Don't worry about the tread design. Its half gone anyway. If you must drive on them in the rain, look ahead to drive on the gray and stay off the black. For your future set of front tires, monitor the wear across the tread as you participate in performance driving events. Whan the wear on the outside half of the LF, assuming most of your turns are right handers, is down to 3/32, its time to flip them. After flipping them, you may want to put the tire with the least wear on the LF, the next least wear on the RF, the next on the LR and the most worn on the RR. This makes sense if you think about which tires work the hardest and those which work the least over one circuit lap.

[SMOODY]

Always put the tires with the best tread in the rear. ... Kevin

I think that this only really applies for traction in the snow. For rain, you want to have the tires with the deepest tread in the front to resist hydroplaning. For dry conditions, the tread depth really doesn't matter much. Although, the deeper tread will have a tendency to squirm more.

[1996 328ti]

Like anything about tires, there are tradeoffs.
All season = no season.

Yes, in the rain it would be better to have tires with deeper sipes on the front but since it is clear more days than rain it makes sense to keep the better tires on the rear. And flipping them will get more mileage out of them. Generally Radial will do them for free as long as you take care of the guys.

[Pinecone]

It depends on whether you prefer to see the crash coming or back into it. Less read on teh rear may mean losing rear traction, especially under braking and IMMEDIATELY turning around.

Best is 4 new tires.

I do NOT rotate tires, and BMW does not recomend rotating tires. Tires on each end wear differently and moving fronts to the back or vice versa can lead to vibration and seriously abnormal wear.

Flipping would work also, just be careful in rain.

[1996 328ti]

I do NOT rotate tires, and BMW does not recomend rotating tires. Tires on each end wear differently and moving fronts to the back or vice versa can lead to vibration and seriously abnormal wear.

BMW does not recommend it because people complained that the car did not handle the same. It was cheaper just to say, don't rotate tires. Just like our water gauges are always in the center unless you have a very serious problem. People complained that their gauges would go up, probably under hard acceleration. Better to pad the gauge to reduce the complaints. What we don't know doesn't cost them anything.

[daddeu]

I do NOT rotate tires, and BMW does not recomend rotating tires. Tires on each end wear differently and moving fronts to the back or vice versa can lead to vibration and seriously abnormal wear.

Every corner of a car's suspension coupled with a driver's style will impart unique wear characteristics to that corner's tire. Assuming the constants of correct tire pressure, properly functioning suspension, and correct alignment, I recommend the following:

1. For cars with identical non-directional tires on all four corners, cross-rotate and rebalance them every 5K miles.
2. For cars with directional tires, all of the same size, rotate front to rear and rebalance every 5K miles. Alternatively, you may dismount, cross-rotate, mount, and rebalance every 5K miles. This reverses the position of the "beauty side".
3. For cars with directional tires that are a different size front and rear, check the balance every 5K miles. Alternatively, you may dismount, remount, and balance the left side tires to the right side which willl move the inside edge to the outside. This also reverses the position of the "beauty side".

Rotating your tires should be considered a maintenance item with the goal of providing the most mileage from the set. Cross-rotating a set of tires as decribed in Item 1 will place a given tire at each of the four corners and impart, over those 20K miles of its life, the most even wear.

[Dirichlet]

Update:
After this weekend autox @ Baysox stadium, my front 235-40-18 Michelin PS2's are officially corded...

Time to order some new tires

[Pinecone]

Every corner of a car's suspension coupled with a driver's style will impart unique wear characteristics to that corner's tire. Assuming the constants of correct tire pressure, properly functioning suspension, and correct alignment, I recommend the following:

1. For cars with identical non-directional tires on all four corners, cross-rotate and rebalance them every 5K miles.
2. For cars with directional tires, all of the same size, rotate front to rear and rebalance every 5K miles. Alternatively, you may dismount, cross-rotate, mount, and rebalance every 5K miles. This reverses the position of the "beauty side".
3. For cars with directional tires that are a different size front and rear, check the balance every 5K miles. Alternatively, you may dismount, remount, and balance the left side tires to the right side which willl move the inside edge to the outside. This also reverses the position of the "beauty side".

Rotating your tires should be considered a maintenance item with the goal of providing the most mileage from the set. Cross-rotating a set of tires as decribed in Item 1 will place a given tire at each of the four corners and impart, over those 20K miles of its life, the most even wear.

My experience has been that rotating tires increased my tire wear due to different wear patterns front and rear. So I stopped rotating, got better life and less vibration.

Now, now, none of our CARS, allow rotation, except the Hoosiers on the LTW.