Tires

[x5joe2013]

I have a square set of Conti DWS on my E70.

Was told that I'm at 3/32 in the rear and 6/32 in the front.

I was planning on just replacing the rears for now, but the shop is telling me it may be hard on the transmission because of the circumference difference between fronts and rears.

Sounds kinda like a load of BS to me.

Any advice?

Thanks!

[mitch808]

Since it's an AWD vehicle, the tire differences need to be within I think 1/16th (Or possibly 1/32) of an inch, or you'll heat up, and prematurely wear out the center diff.

This isn't BS, this is the new norm with more and more AWD vehicles. Often you're having to replace all 4, or find a place that can shave your new tires down to match..

[x5joe2013]

Oh wow really. I'm already at about a 3/32 difference.

Anyone else have experience with this? Is it typical to always have to replace all 4?

[-c-]

Originally Posted by mitch808

Since it's an AWD vehicle, the tire differences need to be within I think 1/16th (Or possibly 1/32) of an inch, or you'll heat up, and prematurely wear out the center diff.

This isn't BS, this is the new norm with more and more AWD vehicles. Often you're having to replace all 4, or find a place that can shave your new tires down to match..

Yep the transfer case failed because of different size tires. Shudders like a boss ! Going to replace fluid first see if that helps.

Replaced all 4 tires. Gotta pay to play.

[x5joe2013]

Did some more research and it looks like the differential tolerance for rotating diameter on xDrive cars is 1%.

So on my 255/50R19 setup that has a diameter of 29" the difference between front and rear could be more the 9/32 without being out of tolerance.

That would basically be totally bald tires on back and brand new on front.

Fortunately I'm not that bad off so I'll just be replacing the rears.

[Mrfurious214]

Originally Posted by x5joe2013

Did some more research and it looks like the differential tolerance for rotating diameter on xDrive cars is 1%.

So on my 255/50R19 setup that has a diameter of 29" the difference between front and rear could be more the 9/32 without being out of tolerance.

That would basically be totally bald tires on back and brand new on front.

Fortunately I'm not that bad off so I'll just be replacing the rears.

So did this end up being ok? My front tires on my X5 need to be replaced while my rears are at 6/32. See my post here (http://www.xbimmers.com/forums/showt...1#post21074301) for more details on my situation. Any advice is appreciated!

[shark715]

Originally Posted by x5joe2013

Did some more research and it looks like the differential tolerance for rotating diameter on xDrive cars is 1%.

Very curious where you found this. I would have guessed more like 2 or 3%.