Cupped rear tires

[mikem1939]

I recently returned from 8,000km trip in my 2002 X5 4.6is. On the return leg I noted a rumble coming from the rear end. It appears that tire cupping is the cause of the noise. The rear tires are 315-35-20s
The X5 has 46,000km on it. Any suggestions on causeof cupping. During the trip I had a chance to run it on a road courseand put some high loads on the suspension.

[C_Dogg]

It's been my experience that proper inflation pressure and balance are the main tools of prevention. Once they are cupped there isn't much left to do, the damage is done. Sorry!

[ewrrod]

October 19, 2003

I recently had a problem with rear tires on my new X5 and would like to know if anyone else has experienced this.
I took in my X5 for it 15,000 mile tune-up. When up on the rack the technician realized that both rear tire had extremely unusual wear on the inside tread. He examined all possible causes (ex. low tire pressure, alignment, impact...etc) and could not find the cause. They concluded it was a defect in the tire. The General Manager told me there was nothing he could do because the tires were not cover under the warranty and would cost about a grand for 2. I then took the car to an authorized Michelin dealer who said the Rear wheels were out of alignment. I had the 2 dealers speak to each other. Both blamed the other.
Anyhow, one guy and the Michelin dealer told me he had seen this before on the X5 4.6. I'm convinced it is a design flaw with the car. Let me explain:
The x5 4.6 is almost 3 tons... That's a pretty heavy car. The Rear tires on the X5 4.6 are extremely wide, I think 12” or so (315/35WR 20). I can only guess but I think the central weight on the frame puts too much pressure/stress on the inside of the tires. It’s only a guess but when I look at the car from the rear I can see that the top of my rear wheel bowl –in and the bottoms out.

If anyone else has experience anything like this please contact me. I having it looked into on a large scale.

[knucklebuster2]

My guess is if the tire pressure is OK, have the camber checked. If it is within specs, BMW may have set the camber specs to allow for better handling. Especially if it is a heavy vehicle. The side effect to the is increased wear on the inner treads.

[blkbty_oz97]

Originally Posted by knucklebuster2

... BMW may have set the camber specs to allow for better handling. Especially if it is a heavy vehicle. The side effect to the is increased wear on the inner treads.

This is correct I am an Australian owner of 4.6is and the camber is set that way, they warned at purchase that i could only expect 20,000kms out of the rear tyres because of the factory camber setting and also that wheel alignments should be done pretty much only by them as the x5 has to be 'weighted' to set the camber /toe in correctly..

Fabulous car though !!! ours is Black with Imola red leather trim

[ewrrod]

Hey thanks for the reply. It IS a great car. I just hate the idea that I have to spend $1000.00 every 15,000 miles for new rear tires.
It also seems kind of danagerous. The Technicial said the tires HAD to be change b/c they'd blow shortly. It's a poor design on BMW's part. But agian, the car is wonderful!
Best Wishes and Take Care!
-EWR

[Menu dei Motori]

Originally Posted by ewrrod

Hey thanks for the reply. It IS a great car. I just hate the idea that I have to spend $1000.00 every 15,000 miles for new rear tires.

-EWR

what do you expect?

15k miles is totally ok. if the costs for new tires are too much you must buy another car. but you should not care. you drive a 70k$car and you should not mind buying new tires!