I'm ready to buy a 2004 a6 s-line. I love everything about it, but I'm concerned about the tires. The car I'm considering has 18" oem rims with summer tires that are worn out. I live in NE Ohio, and we get our share of snow and potholes, so I really need all season tires. And, I've learned over the years that really low profile tires don't work well with potholes. Finally, I'm not inclined to run separate tires for winter and summer.

So here are my questions. . . can I fit tires with larger sidewalls on the 18" oems? What is the largest all season performance oriented tire I can fit without rubbing or adversely affecting the car? Would something like a Yokohama YK520 245/45 r18 fit (it's overall diameter is 26.9)?

I suppose I could look for a similar car with the 17" rims, but I really like this one. If someone could help me solve this tire dilemma, I'll be a first time Audi owner in a heartbeat!!!

 

You really should not change the overall diameter of the tire's circumference, or else your odometer/spedometer will be off. I think the tolerance is 2% or something like that (although I've yet to find that in the DOT standards).

Anyway, you can try to go to a slightly larger sidewall, I think the stock tier on the S-line 18" wheel is 235-40-18. I ssupose you could try to go to 225-45-18 which is just over the 2% tolerance, but it will also be a narrower tire offering less curb protection. You could also try 245-40-18 which is just slightly larger in diameter than the stock tire, but I am not sure if the wider tire will interfere with anything in the car's suspension. I do know that a 255-40-17 tire will NOT fit in a lowered A6 (with the Eibach pro-kit), which has a slightly wider tread but a smaller diameter than the 245-40-18 tire.

Check out the tire size calculator here: http://www.miata.net/garage/tirecalcold.html

 

Thanks Boston Driver. . . I looked around at other posts and see you've had 17" and 18" rims on your car over time. Would you say the 18s made the ride quality noticeably harsher? My wife will drive the car a fair amount. We had an IS300 with the larger rim option and low profile tires, and on two occasions she bubbled the sidewalls by hitting potholes. So, I'm curious if the 235/40r18 tires exhibit similar problems on the audi and it's the primary reason I'm asking these questions?

The second reason is it seems from your pics and others on the forum, you've really made your cars look aggressive by filling out the wheel wells. Do you have to get into suspension mods to make this happen, or will the stock 2004 s-line 18s and proper tire choice come close? This is also partly what I'm trying to accomplish.

I think I've embedded a pic of the car I'm considering. . .

[IMG]local://upfiles/26664/6BFEECB239004F6DAE1829673BB09616.jpg[/IMG]

 

Well, the previous car I had (2.7T) had an aftermarket suspension (H&R coilovers) so I lowered the car about 1/2" or so from the stock sport height. I had 235-40-18 tires on the S-line wheel setup, and 235-45-17 tires on the 17" s-line wheel setup. Both have essentially the same rolling diameter, so they will not really "fill-up" your wheel wells. Besat to stick to those stock sizes.

My current car (4.2) is on stock sport height, with 255-35-18 tires. Yes, a bit more wheel gap than I had with the H&R coilover setup, but I like it.

The ride on 18" wheels is more harsh than the ride on 17s. There just is not as much sidewall protection from potholes, etc., but I findmyself paying a LOT more attention to the road cracks etc. now than when I run the 17s.

I would HIGHLY recommend that you consider the dedicated winter wheel setup. Yes, I supposed you can go all-saeson, but you give up on some performance on either end of the spectrum to get the all-season capability. In addition, you can run very nice wheels in the summer, and not ahve to worry about ruining a wheel in winter, while having better traction in the snow with a dedicated winter tire setup.

I really like those 2.7T S-lines. I see those all the time here in MA, and they always catch my eye!

 

I may eventually go to dedicated winter tires, but for now my purchase of the A6 will have depleted the finances. I need to find a good set of performance A/S that will last for awhile while the bank account recharges. BTW, I live outside the "snowbelt" in my area, so 90 percent of my winter driving is not on snow, although the roads are often wet, and of course cold.

Anyway, I talked to a guy at TireRack who seemed to know his stuff. (Side note: why don't tire retailers show the 18" rims as a stock option for the 2004 A6 s-line?). He suggested bumping up slightly from the standard size to 245/40r18, saying it would give slight advantages in ride and handling due to the small increase in tire width and sidewall height. Can anyone confirm if this is a bad or good idea?

Also, he suggested either Avon Tech M550 A/s or the new Bridgestone Potenza RE960 A/S Pole Position tires in that size. Any thoughts on these tires, or other recommendations for my situation?