Tire Cupping with 19" Michelin Diamaris

[Mr. Incredible]

I have an '05 4.4 with the OEM 19" 132's with Michelin Diamaris and am experiencing tire cupping on the front tires. I check the tire pressures cold and on a regular basis keeping them slightly about recommended (38 PSI F+R). I only have 13K miles on the vehicle and 10K on this tire package (I run snows in the winter). I have approached my dealer who is going to talk with the BMW rep to see if they will authorize an alignment check; although I have not hit anything and the vehicle tracks straight as an arrow at speed. The disappointing thing is that the tires are starting to be noisy at freeway speed and two new front tires are obviously not cheap.

Can I rotate these LF for RF or swap tires from front wheel to front wheel??
Are Michelin Diamaris unidirectional??

Any suggestions, comments, or personal experience with this scenario are appreciated!!!

TD

[Mr. Incredible]

Anyone??

Thanks,

TD

[jroig]

I have the same setup, and use 32PSI all around......when hot, they get 35 and that's in the limit for our roads here in Peru.

They are unidirectional I think.

JRoig

[withidl]

85,000 miles and on my 2nd set of 19" Diamaris tires on my 2001 4.4i S/P which has NEVER BEEN ALIGNED (or curbed) since purchase. The cupping & noise is normal wear. Also, these wide tires wear in the center. which again is normal. I got 50,000 miles out of my 1st set and now have 35,000 on the second set which look to go at least 50,000. The tires are non-directional and the rear tires can be "flipped" on their wheels to counter the negative camber wear thereby doubling their mileage. I carry the recommended 32 psi in all the tires except when towing where I increase the rear tires to 39 psi as BMW recommends.

[SuperGreg]

I love your user name and avatar

[UCrewX5]

38 PSI seems a bit high to me

Michelin Diamaris are not unidirectional, so theoretically they could be rotated side to side. Conventional wisdom has generally discourged this because when radials first came out, changing the directionality tended to cause belts to slip. I really don't think this is as much of an issue with modern tire designs and manufacturing methods.

[withidl]

Originally Posted by El Jeffe

38 PSI seems a bit high to me

My 8,300 pound GVWR trailer tongue weight is 900+ pounds which I weight distribute 1/3 to the front axle of the tow vehicle and 1/3 to the trailer axles. The BMW owners manual recommends 39 psi when the rear is heavily loaded and I've found no problem with their recommendation.

[UCrewX5]

Originally Posted by withidl

My 8,300 pound GVWR trailer tongue weight is 900+ pounds which I weight distribute 1/3 to the front axle of the tow vehicle and 1/3 to the trailer axles. The BMW owners manual recommends 39 psi when the rear is heavily loaded and I've found no problem with their recommendation.

For towing, I agree. But for everyday driving I run mine around 32 PSI.

[SuperGreg]

Originally Posted by El Jeffe

For towing, I agree. But for everyday driving I run mine around 32 PSI.

Yep, 32-34 max

[Mr. Incredible]

Hey all, thanks much for the responses and advice!!

I rechecked my records and I am inflating to 36 PSI (cold) F+R. I feel the minimal loss in ride quality will more than be made up with better fuel economy and tire life (unless this is contributing to my situation ).

So, some of you feel this is "normal" wear and noise?? When I run my hand over the outside edge of the front tires, you can clearly feel the cupping. Remember these tires only have approx. 10K on them.

Again thanks and look forward to futher input/suggestion!!

SG; thanks for the compliments on the user name/avatar!!

TD