Is it just BMW that does not recommend tire rotation?

I agree, rotation will lengthen the life of the individual tire, but the tires will still wear at the same rate as a set.

Here's an example: Because of the large amount of rear camber, my Z3 wears the rear tires (on the inboard edges) twice as fast as the fronts (which wear pretty evenly) . I can either replace the rears only at ~20k miles and get a total of 40k miles out of 6 tires, or I can rotate the fronts to the back and thereby get a bit less than 30k miles out of the original set of 4, and then have to buy 4 new tires.

Plus you either have to swap the wheels yourself or pay someone to do it.

-Fred W

I have noticed most BMWs have a lot of rear camber. Why is this?

Well, I don't own a Viper, but I don't run a spare either. The Nitrous bottle is there. :) And it's doubly crazy because I attract nails in my new tires. 6 month old Goodyears on my Trans Am in 2001 - nail. 3 month Kumhos on my Trans Am in 2004 - nail. Whereas my stupid truck had the same Hankook junktires forever... they wouldn't die, nor did they wear...

(I would take the bottle out and put the spare in before going on a long trip tho... but both flats have been close to home.)

Here's what I've been told.

Dealers don't like doing rotations because very often people come back to complain of vibration, noise, etc. Dealers suggest doing an alignment and dynamic balancing (tire mounted on car), but customers balk at the cost and infer that the dealer is just trying to charge for unnecessary work.

The upshot is poor ratings for the dealers, who need to maintain their customer satisfaction indexes under pressure from BMW NA or CA, so they would rather just not do a job that doesn't make them much money, especially when the car is in for service and the customer requests a rotaion, expecting to pay very little or nothing if the wheels are off for say, a brake inspection.

Never mind the fact that the whole concept of rotating tires is open to discussion at best.

So I've been told by a BMW tech.

Hmm... But new BMWs have all routine maintenance included in the price of the car (notice I didn't say "free") - so what price is there for the customer to balk at?

The negative camber tends to keep the loaded wheel upright when cornering fast and the car rolls slightly. To prevent oversteer.

Tech,

Makes sense to me. I think this falls under the old adage of; "If it ain't broke, don't fix it."

The more time you let someone (including one's self) change things, the more opportunities there are for problems and mistakes.

-Fred W

Neither rotation nor balancing nor alignment is considered routine maintenance - so the customer must pay for these services.

Tom

Mine cannot be rotated as I have different sizes on the fronts! pete

The cost of a dynamic balancing after the rotation, not the cost (if any) to rotate the tires.

I'm glad you see that. I've given this explanation before and lots of people thought it was ludicrous. Your point is bang on. Tire rotation may possibly increase the tread life of tires (especially if you throw the spare into the rotation). But even if it makes sense for this reason alone, a dealer gets absolutely no benefit from your extra tire life, but potentially has all the grief to deal with if you end up with shimmy and shake as a result. I've even hear that service reps will tell a customer, in low tones with a wink "You know, I just can't give you a reasonable deal on a rotation because (insert some stupid justification here), but (and please don't say you heard it from me), Bobby down the street will do it lickety split for next to nothing".

There is no need to dynamically balance the wheel unless the tires are removed and reinstalled on different wheels for some reason. Dynamic balancing is not done "on the car", but rather, on a dynamic balancing machine.

-Fred W

Actually, dynamic balancing can be done either on the car (using a machine made for that purpose) or with just the wheel/tire combo on a balancing machine. "Dynamic" merely means that the tire is spun on the machine and balance is measured in 2 axes, as opposed to the old static balance using a bubble level.

Really, "on the car" balancing should never show much improvement over off-the-car balancing unless the hub is out of balance or the wheel doesn't index properly onto the hub- both mechanical defects that SHOULD be repaired.

Yes, it is a possibility to do "on the car" balancing, but that is not (necessarily) what is meant by dynamic balancing. Dynamic balancing only refers to the idea that the wheel is rotated (either on or off the car) during the balancing.

I'm of the mind that "on the car" balancing is only a band-aid approach to some other problem with the wheel, hub or axle. You should be able to balance a wheel&tire and then mount it on any axle and be good to go.

-Fred W

Well we sure had the ability to dynamically balance tires on the vehicle when I was in school. I know you don't see them very often, but you can do it both ways.