[baymax]

Hi,all I just had a flat tire on my FL tire. The tire depth was 1mm for FL and 4mm for rest of all. Those were changed right around, maybe little less than a year ago. Since I am changing the FL tire, the dealer also suggest me to change FR to aviod any damage to transfer case and differential caused by tire depth difference. Is that true? Does that few mm of difference on a rubber tire really can damaged the metal transfer case and differential? Thanks in advance!

[micvite]

Originally Posted by baymax

Hi,all I just had a flat tire on my FL tire. The tire depth was 1mm for FL and 4mm for rest of all. Those were changed right around, maybe little less than a year ago. Since I am changing the FL tire, the dealer also suggest me to change FR to aviod any damage to transfer case and differential caused by tire depth difference. Is that true? Does that few mm of difference on a rubber tire really can damaged the metal transfer case and differential? Thanks in advance!

Realistically front l to front r isn't gonna make much different... front to back might. Also concerning is why you have an essentially bald tire with 3 that are half health. Somehow audi was able to figure out how to make an awd system where tread depth didn't matter, mercedes and bmw have not lol.

Front diff is an open diff so it doesn't matter what tread u have left to right, it's only purpose is to change the direction of spinning of the driveshaft from forwards to sideways. That being said your transfer case may be active when it doesn't need to be thus burning out or even overheating and going into limp mode because the car will think the tires are slipping due to the difference in circumference front to back. I can tell you with certainty this transfer case overheats in about 2-3 minutes if not less (from experience doing 4wd drifting) but at that point the car will just disable the awd and call it a day😂

[oneofew]

If it's not a budget issue absolutely change it. You'll have 2 equal tread brand new fronts.
I would be more concerned about how my car is going to track with one brand new and half worn tire than damaging the transfer case.

[pmsteinm]

I too would be more worried about why 1 tire wore faster than it's mate on the same axle. Unless your daily commute is in circles that would indicate a problem with alignment and/or tire pressure.

If I ever have to replace a tire that is more the 1/2 way worn out I replace the other on the same axle too. This hasn't been a problem for me much since my tires generally only last 10-18k.

If you elect to only replace one, do this test after: Get up to 60 on a straight flat road and do a full ABS panic stop with your hands off the wheel (brace using your left leg on the dead pedal). If the car doesn't track perfectly straight you have problem (tires/alignment/brake/suspension).