Helmar

I posted this on the A7 forum, but then it occured to me that this is as much an A6 question as an A7 question.....

I'll be ordering an A7 to replace my 2008 Lexus LS Hybrid next year. I no longer need such a large car.

I'm planning on having the dealer mount 18" wheels with all-season tires instead of the standard 19" wheels, even though 18" wheels aren't available.

Why?

1. Living in Maine, I'm concerned about driving in heavy snow. 18" wheels/tires would do better (True?). Mostly because of the ride height.....

2. Ride quality (smooth and quiet) would be better.

3. The car would ride slightly higher which is usefull in heavy snow.

Any comments on where I'm going wrong on any of the above concerns would be most welcome.

Also, are there any technical issues with doing this, such as the odometer reading wrong because of different size tires?

Will a dealer do this at no cost, or should I expect to have to pay additional for this?

HBH

AUDIQSS

A short answer to a complicated question. To accomplish your goals you need a narrower and taller tire than you are getting from Audi on your car. Narrower to cut through the snow and taller for ride clearance. For example a 245/55/18 or 235/60/18 vice the 240/55/19 the A6 comes with. These two tires would raise your ride height by 3 to 4 centimeters. You would still want a high or ultra high performace tire and in those sizes your choices are limited. Also by requiring new rims as well, it is highly unlikely your dealer will do it for free(unless you are married to his daughter, then all bets are off). Good luck!!

snagitseven

This is not correct. Regardless of wheel size, you have to stay with a wheel/tire combo matched very closely to the same circumference as the OEM wheel/tire which will not raise the ride height one bit. An 18" vs a 19" with a tire having the same circumference will have a smaller wheel and a taller sidewall. The chassis ride height will be identical.

tenspeed

Plus and minus sizing of tires couldn't be easier with the A6/A7. Just look at the wheel choices in the brochure.

A6
245/45-18
255/40-19
255/35-20

A7
255/45-18
255/40-19
265/35-20

It's interesting that the A7 18' and 20" tires are slightly wider than the A6. That would make them slightly taller. That would make the speedometer indicate a slower speed than actual on the A7 unless there is a correction factor.

AUDIQSS

I disagree that you HAVE to retain the same tire circumference as the OEM. That is true IF you want the odometer/speedometer to remain accurate. If on the other hand you are willing to give up that accuracy in exchange for a small increase in ground clearance you can go to a "taller" tire (as long as it still fits in the wheel well). After all, the poster described several goals: making it through deep Maine snows, better ride quality (smoother), and increased ground clearance. He seemed willing to forego odometer/speedometer accuracy.

As for my personal bias: I would retain the OEM circumference and go to a winter tire (17 or 18 inch) if I was that worried about deep snow. Here in Virginia, I am simply keeping my 255/40/19 size and switching to all seasons next week. Anybody want to buy a set of OEM 255/40/19 summer tires with only 1,000 miles on them?

irenesbob

I am not sure these are the only concerns (speedometer and odometer). Someone far more technologically informed than I might be able to resolve this (snagitseven?), but I think it is possible the gremlins that run the ABS and TPMS systems might find a different overall tire height/diameter perplexing.

snagitseven

Besides the potential technical issues you mentioned, there's the appearance. Would anyone want their $60K luxury sport sedan to resemble a jacked-up Jeep Rubicon?
If Audi wanted you to have more ground clearance, they would have offered it. Wait...they do. A Q5 and Q7.

tenspeed

That is true. The ride will be slightly higher and there will be a error in the MPH and the miles traveled. The ABS and TPMS will not be effected because they compare the relative speeds and relative pressures of the wheels, not the speed over ground.

I have slightly larger snow tires on my DD. The odo/speed is 3% slow so my indicated speed is 2 MPH lower at 60 MPH and I travel 103 miles for every 100 indicated. I didn't get them because of ride height. I bought them because I got a great price on a set of Conti Extreme Winter Contacts.

Grapeking

There is also the question of potential rubbing, either on suspension parts or on the fender lip. That said, I took a chance and installed 245/45/19 (slightly oversized vs stock) as I wanted more sidewall under the tire for winter use. No rubbing whatsoever....but the speedometer is a bit off (1.5 mph at 60 mph)so I take that into account.

AUDIQSS

Sangitseven: To use your reasoning, if Audi wanted you to use all season tires on your 19" sport package, they would have installed them. The same goes for paint protection, etc.

No manufacturer is about to please all customers, that is why the after market exists and why we individually do what we do with and to our cars. Rather than telling the poster what YOU think he should do with his car, help him accomplish what HE wants to do with it. Now I will shut up.