[Metalgear]

Is it true about BMW all wheel drive vehicles or all wheel drive vehicles period. If 3 out of 4 tires are good. I shouldn't just replace one tire. I should place all 4. I have one tire on my vehicle that have a knot/ broken belt on one of the tire. But the other 3 are still good. No matter what I have to replace it. I was told by tire shop that since it's a all wheel drive. Dealer recommended to change all of it. but the tire shop want me to sign a waiver. That stated they have told me to cover their A$$. What is the recommendation? Is it ok to replace one or replace all? Any advice?

[lesha]

tire shops will tell you a lot of things to make $$$

[Metalgear]

So have anyone heard such a thing? If that is not true. I'll sign the damn waiver?

[Red Bread]

You're always supposed to change both tires on the same axle together (both fronts, or both rears) especially if there's a limited slip involved. I'd say that with a permanently engaged awd system like BMW, Audi, Subaru, Mitsu and most use, it would be in your best interest to replace all four tires together, I always did with quattro Audii. If it's a Haldex system like VW uses, and the Audi TT, then you might be able to get away with it.

Why risk differential wear to save a few bucks on tires. Just out of curiosity, was the tire with a sidewall blister a Goodyear RS-A? I had those stock on an Audi and it's the only tire I've seen do that consistently.

Here's Tirerack's take on it:
http://www.tirerack.com/tires/tirete....jsp?techid=18

[Metalgear]

Yes it's a proven fact. I have a friend that is a Manager at a tire shop. Told me what happen to one of the customer. That they wanted to change one tire. but he did not have them sign a waiver. Cost the shop $2.500 to have the customer transfer case fix on their car.

[Metalgear]

This is from the BMW Senior Service Advisor.

If the other tires are at or above 50% then you will be fine to replace just the one. Otherwise I would replace them in pairs.

[footie]

Replace both tyres per axle, no need for the full set to be replaced.

[Spec 1]

I'm with the rest on replacing both per axle, unless you have above 70% tread on the other 3, then I'd say you're fine with just the one.

[Freakazoid]

for AWD cars (like subbie, bmw etc), it's definitely better to replace all 4 if you can afford it.

Of course that depends largely on the tread. If the other tires are all under 50-75% tread, you REALLY should. Other than that, you'd probably be generally safe without it.

[scheherazade]

Rotate tyres often so they wear evenly.

Patch tyres, don't buy new ones.

You'll be fine.

-scheherazade

[footie]

Originally Posted by scheherazade

Rotate tyres often so they wear evenly.

Patch tyres, don't buy new ones.

You'll be fine.

-scheherazade

Can't speak for x-Drive because I haven't had enough personal experience of them but will Quattro (torsen version) the wear is generally quite even front to back though depending on whether to have many roundabouts you might see more wear to one side. The Haldex version which is fwd biased wears more to the front which is to be expected.

The cars which are equipped with the torque vectoring diff like the X6s and S4s these are more tricky to determine, it will depend on how hard you drive.

[kinan_sleiman2006]

Sure man...You have to replace all the tires in the same date

[b0bab0i]

BMW's AWD system is different from Audi & Subaru's i believe.
BMW's AWD is based rear wheel drive in normal conditions. Once computer senses revolution difference between front and rear it activates front drive.
(correct me if i'm wrong)

I agree with everyone above in replacing pairs unless its above 50% tread, then just replace one.

BMWS AWD/Xdrive is a crap compared to Audi's & Subaru's.

[footie]

Both x-Drive and Quattro (2006 onwards) all are rear bias to 60% in normal conditions, the difference is that in the most extreme situations the x-Drive can shift all of it's torque to the front or rear wheels, unlike the Audi system which can only shift up to 65% front and 85% to the rear. Though the reality is that neither system in anything other than snow or ice will ever likely shift all of it torque to either axle, so in reality both system will perform quite similarly and the likelihood is their tyre wear will also be similar.