Tire Issue? Or not?
 

I Bought a 03 X5 4.4l in September. In December the Tranny let go. After a two month ordeal over getting the tranny rebuilt. She is back and driving great. Although it does need tires. So after shopping online I noticed that my particular x5(with sport package and 19's) should be running 255/50R19's on the front and 285/45R19's on the rear because of staggered rims. So I then went outside to check what the vehicle has on it now because I never really paid much attention. I found that someone has put 255/50R19's all the way around. Stretching them over the wider rear wheels.

My questions is this. Could that have been what caused the tranny problem to begin with? Will it hurt me to continue driving the x5 until I get new tires? Or should I park it? Any input is appreciated. Thanks

No way, it has open diffs front and rear. I run staggered in the summer and straight setup in the winter with no problems at all!

I even changed the fluid in my xfer case and it was like brand new :)

The front/rear diffs would only be effected if different diameter tires were place on the SAME axle, not front/rear stagger.

Front/rear stagger effects the transfer case, you have an open transfer case and you have ZERO front/rear stagger with the same size tires all around.

Tires had no cause connection to trans failure.

Ok. Great! I was just thinking that having the same size tires stretched over a larger rim in the back may change the circumference front to rear. Thus causing an issue. Glad to hear it will not. Although, I am going to go with factory recommended tires this week. Thanks for the quick reply!

But stretching a tire lowers it's overall diameter so it's possible to have the same size tire on all 4 corners but have different overall diameters

All e53's have open diff's ( front and rear )... it is not going to hurt anything cause a transmission failure

That's what I thought. Because the wheels are 19x9 F and 19x10 R. This would make for different overall circumference front to rear. But is it safe to drive this way? Or am I asking for trouble?

Your fine, just don't try to rotate the rims front to back! you *could* have some clearance problems...

buy the right sizes when you replace them ;)

Will do. Thanks for the help!

Making the assumption that "the wheels" are the staggered BMW Style 132 19" wheels...see the chart below after running that wheels' specs (width/height/offsets) with the same size tires mounted.
Looks like once mounted...the tire's width is the same at the bottom (where the rubber meets the road :) )...and the overall height/diameter will still be the same (29.1")...even though the rear tires are stretched over a slightly wider wheel.

Hope this helps calms any fears. :) The wheel/tire calculator site used was: Custom rims, wheel tire packages for your ride - RIMSnTIRES.com