Stock Wheels and Tires versus Oversize?

[djvandrake]

Hi. Forgive my ignorance but I've got a problem with my car that I'm not sure how to solve.

I recently (8 months ago) bought a 2001 530i E39 and I really enjoy the car. It came with a set of 18" non-factory wheels, and the tires were about shot. So I got a new set because I had to, Eagle GT's at 245/45 R18's. (the size on the car already). I'm not real happy with the tires but the alarming thing is I burned the back tires down to zero tread in only 5600 miles. It was even wear on both back tires. Just before I got the new tires I had to replace the rear ball joints, right rear control arm, and the front tie rods. I then got a professional alignment so it's spot on. It should not be a suspension problem. I then went back to the place of purchase and they replaced the back tires only because of the ridiculously fast tread wear. Well that was about 2500 miles ago and the rear tires are already over half gone. :mad

Looking in the door jam of my car I see the factory recommended wheels and tires are: Front, 235/45 R17 and Rear, 255/40 R17.

Has anyone ever experienced a similar problem when running tires larger than the stock size? I obviously can't afford to repalce the rear tires every 3 months, and need to fix this somehow. I hope to figure out why this is happening before I do something very expensive like relpace the wheels with 17's.

Any advice would be appreciated. Thanks.

[Kyle Anderson]

Are the tires wearing evenly all across the tread, or is it on the inside edge?

[RenegadeE36]

Stop doing burn outs all the time!

No really, that new size is nearly 2" too tall. Why not put 255/35/18 on the back and 235/40/18 on the front. These sizes are going to give you nearly the same outer diameter as stock.
If you know the alignment is right and you have checked the all the bushings and other suspension parts, I think the right size tire would be the next step. Put these on and do another alignment check.

[djvandrake]

Are the tires wearing evenly all across the tread, or is it on the inside edge?

The wear is completely even across the back tires and there's no sign of unbalanced wear.


Stop doing burn outs all the time!

No really, that new size is nearly 2" too tall. Why not put 255/35/18 on the back and 235/40/18 on the front. These sizes are going to give you nearly the same outer diameter as stock.
If you know the alignment is right and you have checked the all the bushings and other suspension parts, I think the right size tire would be the next step. Put these on and do another alignment check.

Thanks for the adivce. So the tires being too tall will / can cause the accelerated wear I'm seeing? Makes sense if it affects the weight distribution across the wheelbase? Would it be better to go back to 17" wheels or stick with the 18's and alter the front / rear sizes as you suggest?

Thanks again.

[RenegadeE36]

I don't know if that's causing the problem but it sure can't be helping anything.
If you like the wheels you have just get the right size tires. Or maybe buy some used factory wheels until you find out what's going on. Buying 18" tires all the time can't be cheap.
That wear is so fast something else must be going on.
I'm sure it was a four wheel alignment right? I know some shops try to get away with just front.