Tire wear

The tires on my 2007 BMW X5 are wearing out on the inside after 30,000 miles. The dealer says this is normal because the way the wheels are canted to better grip the road causes excess wear on the inside of the tire. Nyone else experience this?

Front or rear tires? Or all 4?

all 4

Unless the dealer did an alignment check first, then I would conclude you need an alignment, to see if it is within BMW specs. I am not a BMW owner, but I expect my vehicle to be aligned to manufacturer’s specs, so that the wear pattern is pretty much uniform across the tire, with a proper tire rotation schedule. I think you need a 4 wheel alignment, so you find out what’s going on and correct it.

All too often, “that’s the way they are” is an excuse for inaction and lack of diagnosis.

Some people intentionally cant their tires in at the top in the mistaken belief that they will get better handling. I’m pretty sure that the BMW engineers know better than this. If your dealer is trying to avoid having to do an alignment, then the alignment must still be under warrantee. If its not, you need to find an independent shop specializing in alignments, particularly on BMW’s.

Sorry, Keith, but not only is camber a standard way to get more cornering power (Look at the front tires of an Indy car set up for a road course!) - and BMW specifically dials in more camber in order to take advanatage of this - but that generates inside tire wear - a common problem for BMW’s. Then to compound the problem, BMW recommends against rotating tires because the handling goes down immediately after a rotation. The fact that their alignment specs will cause the tires to wear funny doesn’t seem to be a concern for them.

No, the dealer is right, this is normal for a BMW.

I would have an independent alignment shop take a look at it. It would be worth it to me.

That said I once had a car that had 7.5? setting on the front. I remounted the tyres to wear out the other side and at about 80,000 miles I had to replace them. Since 12 inch tyres are not easy to find, I had to use mobile home tyres. I got another 80,000 plus out of those before I sold it.

You clearly are one of those people who mistakenly believe that increased camber increases cornering power.

Under hard cornering, a tire rolls to the inside of the rim. That is the rim goes toward the outside of the turn as the tread doesn’t go as far, thats traction at work. The inside of the tread lifts off the road slightly. With lower profile tires, this lifting is lessened. Now increasing the camber on the outside tire will offset this lift. If the camber change is perfectly matched to the lift, then the maximum amount of tread will remain in contact with the road.

So far it seems like I’m supporting your argument, but here is where it fall apart. When you corner hard, the car body rolls to the outside of the turn, compressing the spring on the outside, increasing the camber of the tire to offset the roll. Adding too much static camber will leave the outside tread off the pavement reducing the contact patch area.

Now there are two tires on the front. The inside tire is also contributing to the total traction. If it starts out with too much camber, the tire roll will lift even more tread off the pavement. Now it is true that the body roll will decrease the compression on that spring, decreasing the camber, so that will help, but if it starts out almost vertical, then the camber will go negative enough to compensate for the tire roll.

It take s a lot of engineering to match the tires to the suspension geometry. A major change in one or the other can often lead to poorer handling and increased tier wear, often the opposite of the desired affect. Some manufacturers have optional packages available for upgrades for those willing to sacrifice a smooth ride. You have to do the complete package, not just part of it.

BTW, indy cars spend more time turning left than going straight and the front tires have different cambers, and they only last about 100 miles. Indy cars have very little body roll so a little starter camber on the right tire is necessary.

One more thing. When the factory call for increased camber, they also usually call for a little toe in to offset the additional wear on the inside of the tires. Correctly aligned, the tires should not wear only on the inside. The camber and toe in will cause shorter tire life and some additional drag on the vehicle.