Hi, all. I have a 2005 A6 with 245/45R17 tires on it. My brother-in-law just offered me a set of Blizzak snow tires (plus the wheels they're mounted on) - they're 255/40R18 and they came off of his 2007 S6. Can anyone tell me if these will fit my car before I make an effort picking them up and installing them? Will they be too wide or too tall and rub somewhere?

I don't see any documentation that this size will fit my '05 but sometimes you guys know better.

Thanks for any/all assistance.

 

These WILL NOT fit your wheel. The last number in the sequence tells you what size wheel they are meant for so for instance your tires now at 245/45R17 are about 245mm wide tire and the sidewall height is roughly 45% of the width. R17 tells you it's got to go on a 17" wheel. The 255/40R18 is telling you that the tire is about 255mm wide with the sidewall height being roughly 40% of the 255mm width and they are meant for an 18" wheel. Also as a general rule for a winter/snow tire, you generally want to go a little bit narrower than your standard summer tire.

 

Thanks, Mwink. It's actually not a wheel issue because as I said in the original post, the tires are already mounted and he's offered me the tire/wheel package. I was just asking if that tire (already mounted) would fit on my car in terms of the clearances.

I'm interested in your suggestion that snow tires should be narrower than typical all season tires. Any idea what the logic is behind that rule of thumb?

 

Sorry, the wheel should fit without an issue depending of the wheel's offset. As for having a narrower width for a winter tire, the idea is to go narrower so that the tire digs into snow and bites to give you better grip as opposed to a wider tire which will tend to run up on snow and slide. Think of it as having a sled with rails versus a flat sled. The sled with rails tends to dig in where the wide flat sled just planes across. Going from a 17" wheel to an 18" wheel is fine as long as the bolt pattern, centerbore and offset are correct. Sorry about the incorrect info in the first reply, I'll blame that on my not reading the initial post carefully enough,.

 

Thanks for the explanation - that makes sense. I ended up speaking with someone at my local Audi dealership and he said that the wheels should fit without any trouble and that the tires should fit, too, based on the information I have.

Thanks again for your input.