AWD 330xi Tire Replacement

[leobimmer]

I got a flat tire that is beyond repair a couple of days ago. (front)
I have been getting conflicting advise regarding tire replacements.

My question is, since it is an AWD car, do I have to change:
(1) all 4 tires

(2) just the front tires

(3) just the flat tire


Thanks

[cwsqbm]

It depends on the amount of wear and mileage on the other three tires. If the mileage was low, I'd replace just one. If the mileage is higher, look at how the fronts are wearing different than the rears. You'll notice that both ends aren't worn identically, so replacing two isn't a big deal. However, at the point take a hard look and see if you've close to replace all four anyways. I hope this lack of an answer helps.

[leobimmer]

Hi cwsgbm:
Thanks for your advise.

I took the car to a nearby dealership and after they looked at the thread wear on the other tires, they determined it was OK to just replace just one tire.

[Watchdog]

Hi cwsgbm:
Thanks for your advise.

I took the car to a nearby dealership and after they looked at the thread wear on the other tires, they determined it was OK to just replace just one tire.

I'd get them to put that down on paper.

They may be right based upon tire wear, but I have heard stories of only 1 tire being replaced when the other tires were worn significantly and since the new tire was a slightly bigger diameter than the others the AWD system viewed the other tires as slipping all the time and redistributed power constantly and it burned out the AWD system.

I was in a similar position to you, but my tires had 60k km's on them when I got a flat, so I figured I should replace all 4.

[dbh1]

Same issue.

I have a 2006 330XI with 225/45HR17 Michelin XSE Pilot Exalto A/S tires. One of the tires has a bubble and must 60. The others are probably 50% worn or so.

My thoughts are to replace with Continental SST All Seasons RFT of the same size since they seem to be reasonably priced, fairly well reviewed and have an above average warranty.

Ideally, I would just replace 2 of the tires. I know it is not ideal to have different tread patterns, but I assume that is primarily a left/right issue and not as much of a front/back.

The other concern is the thickness of the new tires vs. the old. This is mitigated by BMW allowing for 18 & 19 inch wheels to have different front and back sizes. If my math is correct, the rears tend to be ~20mm wider and the fronts 1-2.5mm taller. This would imply I should put the new tires on the front? Also, the tread-ware is probably a bit more than 2.5mm, so am I above tolerance.

What about an extra 1 psi or so on the older tires?

BTW, I bought my car used with 16k miles. I assumed that the Michelin's came original on the car, but most owners sound like theirs came with Bridgestones or Contis. Am I now looking for the car's 3rd set?


THANKS.