Slave IV

I've seen that tires should be the same make/model/size all around and wear should be within 4/32" of each other or you could do damage to the transmission/AWD system.
There are also cases where people are staggering the wheels with wider in the rear. I don't think it would be possible to match the diameter of the front and rear tires exactly (or within 4/32") so are these people risking damage or not? It seems like it shouldn't be a big deal as long as the front or rear tires match since there are several AWD cars on the market with different size wheels in the front and rear. If this is the case, will I be OK to run two different makes/model tires for the front and rear on my stock rims without worry? Thanks.

Slave IV

I don't want to stick with the same tires but they are pretty new for me to replace all of them. Will I be OK if I get two tires from a different manufacurer but same size (225/45-17) for now or do I have to get 4 new tires just to replace one bad one?
Here's the old post:
<a href="https://forums.audiworld.com/s4/msgs/2702499.phtml">click</a>

Also, still interested in the different size question as I plan to stagger my wheels when I go WB, if it's safe.

amercour

I need to replace two tires as well. Would it be ok to have 235 in the back and 225 in the front?

Jsmooth65

and it made a hell of a racket while driving. Sounded like a wa wa wa wa wa. I had 255/35/18 Falkens on the rear 9" wheels and 225/40/18 Generals on the front 8 inch wheels. Changed them to all Bridgestone Pole Positions with 225/40/18 on front and 245/40/18 on the rear and she sounds smooth as silk. Don't know if that helps, but maybe you can breathe a little easier. BTW, the PO drove the car like I mentioned earlier for about 7 months, car seems fine.

Slave IV

short time periods but I'm also interested if there is long term damage that can occur over time if someone were to go with a permanent setup with different sizes.

Slave IV

myself. From STFA, I've seen people say it's bad but never explain why.

HIS4

The differential with your old set was only 0.1" which is well within the tolerance. Your new set has a size differential of 0.6" which is quite a bit more than the 4/32" recommended.

Christian (Stage Ow)

If you run grippy tires in the rear, and slippery tires in the front, quattro and ESP will be working overtime to figure out what the hell is going on.

Best to stick with four of the same tires.

Jsmooth65

yeah, you're right. The static loading radius comes out to about a .4" differential, which is slightly better than 0.6". At the time, this was my only option, since I had lots of Firestone credit, needed tires, had staggered wheels from PO, winter is approaching. SO I took it. Car doesn't make noise like it used to, so I'll chalk up a win and overlook the .125" rule.

Slave IV

"quattro and ESP will be working overtime to figure out what the hell is going on"
the best explanation for what actually can go wrong. If it's just a case that the system will work harder and that's why it's bad, fair enough. But I'm tired of people who do things without understanding the reasons behind it other then someone saying, "it's bad".
The "working overtime" explanation seems like a software issue that can possibly be resolved. Is there more specific detail on what else can go wrong?