davepjr71

The A7 I just purchased has Kuhmo ECSTA PS91's (summer tire) on the rear and Cont DWS's on the front. I'm assuming that the Kuhmo's that used to be on the rear wore out so they moved the Kuhmo's to the rear and put Conti's on the front for when the MD state inspection was done but not sure as it's odd to have 2 completely different tires. They both look to be in great condition. Will this cause problems with the AWD on the Audi? If I need to replace one of the 2 would you keep the Kuhmo's and try to sell the Conti's or vice versa? I'm thinking about buying winter tires with 17" rims next winter if that has any bearing on which way to go.

The Kuhmo's are around $220 a piece and the Conti's $270 or so.

Thanks ahead of time.

19hole

You really want to have 4 of the same tire on the car. The differences in tire compound, grip level and handling can result in some pretty unpredictable driving. Keep the DWSs all around.

davepjr71

I found 2 used Conti DWS 06 with about 8-9/32" left. Mine are DWS with 6/32". Is that too far apart?

19hole

Personally, I would never buy used tires. You have a car that has a fair bit of performance potential. It is also a car that new was probably north of $70,000. Go online to tirerack.com and buy your self 4 new tires for your car. I re-tired my S7 last fall with 20" Michelin Pilot Sport A/S 3+ for about $1100.

davepjr71

Can' find that tire now and all the Michelin's they have are over $300 a pop. I understand what you are saying about the car and performance. The tires I'd be putting on have a lower profile than the 255's that are listed. I'm at the dealership now getting the fuel line recall done and will talk to them about it. The definltey said the mismatched tires can damage the rear differential. Thank you.

19hole

I put these on my S7, they are pretty quiet and handle pretty well.

davepjr71

I was looking at the 265/35/20's. No wonder I didn't see these. Will have to take a look. I'm amazed those are so much cheaper than the 265/35/20's. Thank you.

superswiss

This is clearly stated in the owners manual. All four tires should be of the same brand, thread pattern and size and similar wear level. There is a certain amount of tolerance that is ok. Audi states up 4/32" difference in thread wear is ok. Tires from different brands even if they are the same size could have different diameters and circumferences putting you out of tolerance. Even a different tread design from the same brand could do it. And as mentioned above different compounds and tread designs have different grip and characteristics which could lead to all kinds of issues. It could cause false positives in the ESC for example or the car could get out of control in an emergency situation due to the unbalanced tire situation. Being out of Audi's tolerance could overheat and damage the center differential and you wouldn't be the first one.

davepjr71

I just came from the local Audi dealer. At 1st the manager said what you are saying and was concerned about the rear differential. Then Tech said I'm fine with the mismatched since both rears are the same and front are the same and they are basically new tires with the same diameter with barely 2/32 difference.

I do intend to pay attention to wear and am buying 18" Contie on A6 rims that I will use for the winter and when the tires wear or difference reaches tolerance I will replace the 20's. Probably next spring. I appreciate the input.

tenspeed

It was the same way for the Conti's DWS 06's when I was pricing. The next size larger was around $250 less for the set. Supply and demand I suppose.

edit: found this set of 18's in NJ.
https://www.audizine.com/forum/showthread.php/803273-Wheels-and-Tires-!8-x-8-with-Continental-DWS-Tires
https://www.audizine.com/forum/showthread.php/800358-18-quot-Wheels-18x8-with-Continental-ExtremeContact-DWS-245-45ZR-18