[mblaucoupe135]

I was driving in the mountains this weekend and ran over a rock that punctured the sidewall of my tire. I'm currently looking for a replacement now but my question is, will replacing one tire with a new one with more tread cause any issues with the xdrive system? The tires are Blizzak LM32 and I'm thinking they have enough tread to get me through at least one more winter.

[Joe240]

Should be fine. The rolling diameter difference shouldn’t be enough to affect the xdrive. Hell, the factory staggered set is 1.3% and xdrive is fine with it

[mblaucoupe135]

Originally Posted by Joe240

Should be fine. The rolling diameter difference shouldnÂ’t be enough to affect the xdrive. Hell, the factory staggered set is 1.3% and xdrive is fine with it

Ok that's makes me feel better. I didn't think it would be quite that sensitive but thought it was worth asking.

[Maynard]

Sorry to be a killjoy, but standard recc would probably be to either replace all 4 or shave the new tire down - you'd have to measure it, but IIRC the new one should be w/I 2-4/32 of the old ones? Check this w/ somebody like Tire Rack for the clearances specific to BMW.


https://www.tirerack.com/tires/tiret...jsp?techid=259

[mblaucoupe135]

Originally Posted by Maynard

Sorry to be a killjoy, but standard recc would probably be to either replace all 4 or shave the new tire down - you'd have to measure it, but IIRC the new one should be w/I 2-4/32 of the old ones? Check this w/ somebody like Tire Rack for the clearances specific to BMW.


https://www.tirerack.com/tires/tiret...jsp?techid=259

That's good to know and I'll see if I can get the new tire shaved down to match the other 3 on the car. Thanks for the info.

[TajoMan]

It's mostly to cover their ass from blame game.

Also, matching tire tread depth applies only to same axle.
AWD center diff mostly won't be affect since wheel speed difference will be taken care by differential in that axle.
(As mentioned above, staggered setup already had 1.3% difference in circumference anyway)

1~2 percent difference could easily happen from tire pressure.

I would worry more about uneven grip level, especially for winter tire.
Winter tire has 2 different wear depth, one for snow, one for normal road.

If your tires worn down below snow thread wear mark, you will not get proper snow grip.

If it worn down below snow mark (as OP mentioned it may have 1 more season left), I would just change all 4.

[Xi-Xi]

[QUOTE

https://www.tirerack.com/tires/tiret...jsp?techid=259[/QUOTE]

This strikes me as a load of hooey. Don't worry about it, OP. Differential heating of the tires during driving as well as normal wear (which may not be completely even) is enough to cause variation among the tires.

I blew out a sidewall on my front right tire two weeks ago in a pothole. Called BMW roadside assistance. BMW replaced the tire the next day (free loaner was great), and I was on my way. When the other three tires need replaced I'll buy all four, and use the right front as a spare.

[p912guy]

The difference between cost no object, ideal / perfect world solution vs real world solution.

[mblaucoupe135]

Originally Posted by TajoMan

It's mostly to cover their ass from blame game.

Also, matching tire tread depth applies only to same axle.
AWD center diff mostly won't be affect since wheel speed difference will be taken care by differential in that axle.
(As mentioned above, staggered setup already had 1.3% difference in circumference anyway)

1~2 percent difference could easily happen from tire pressure.

I would worry more about uneven grip level, especially for winter tire.
Winter tire has 2 different wear depth, one for snow, one for normal road.

If your tires worn down below snow thread wear mark, you will not get proper snow grip.

If it worn down below snow mark (as OP mentioned it may have 1 more season left), I would just change all 4.

yeah that's a good point about a potential issue with winter traction having one new tire and three older, more worn ones.

[mblaucoupe135]

Originally Posted by Xi-Xi

[QUOTE

https://www.tirerack.com/tires/tiret...jsp?techid=259

This strikes me as a load of hooey. Don't worry about it, OP. Differential heating of the tires during driving as well as normal wear (which may not be completely even) is enough to cause variation among the tires.

I blew out a sidewall on my front right tire two weeks ago in a pothole. Called BMW roadside assistance. BMW replaced the tire the next day (free loaner was great), and I was on my way. When the other three tires need replaced I'll buy all four, and use the right front as a spare.[/QUOTE]
I have to agree that roadside assistance was really good and responded promptly. problem is the winter tire I have has been discontinued so my service advisor couldn't find a replacement. also, now that I've looked at the remaining tread, it might be best just to buy a new set of four before next winter as they are down to about 5/32.

[Transfer]

I would consider at least buying two new tires depending on tread depth of contralateral tire and front to rear sizing. Then you can use up the remaining two tires or replace them at another time.

[Ron Jeffries]

the cars do have differentials. an honest tech would give you good advice based on the actual tires. I always replace two at a time because I am OCD.

[mblaucoupe135]

Originally Posted by Transfer

I would consider at least buying two new tires depending on tread depth of contralateral tire and front to rear sizing. Then you can use up the remaining two tires or replace them at another time.

yeah that might be a better option.