hi gang...

I presently have Michelin 255/40ZR17 (diameter 26.1") tires on my 2001 A6 4.2 Is bigger possible with stock suspension??? thanks ahead of time... jtv4.2

 

That's generally considered as wide as you want to go. Why do you want to go wider? What effect are you hoping to achieve?

 

Two reasons for wanting more diameter/ bigger tire... 1. for my winter tires, I live in northern lower michigan 70-80 inches of snow. soooooo I need as much road clearance as reasonably possible. (narrow but taller) Goodyear tripletread are my choice (I have a set on my wifes 2002 A4) 2. back for summer driving now, I love wide tires for cornering & stability. does anyone have larger then 255/40 17 ???? thanks gang jtv4.2

 

oh by the way southboroaudiguy... I like your wheels. nice lookn car... I have not decided on 18' or 19 for summer tread. I will post a pic when I get my car washed and detailed. thanks

 

Not sure what having a bigger diameter has to do with winter driving. I also live in the snow belt and have dedicated snows. I run 215/55s on 16x7" wheels. You should probably be looking at something similar -- probably 225s or 235s on your 17x8 rims -- for your winter wheels. Narrower is better so the tires can bite through instead of riding on top of the snow.

As for your summer wheels, you probably don't want to go larger than 255s -- you may run into fitment issues. That's an awfully wide patch anyway so I don't think you need to worry about performance. As for the diameter, you can go with either 18 or 19 inch wheels. The key is to use the "plus concept" of going down in aspect ratio as you go up in wheel size so that the outer diameter is maintained. Going from a 17" to an 18" wheel will produce a very noticable difference. You'll get better turn-in and more road feel. That last one is a double edged sword. Meaning, you'll get better performance but along with it will come a loss of ride quality.

<soapbox>
I'm of the opinion that 19" wheels do NOT belong on an A6. NONE of the people I communicate with regularly use that size when putting the car on a track (many weekend racers use 17" wheels!) so it's obviously not a performance requirement. Everybody I've spoken to who's opinion I know I can count on say that the loss of ride quality when going from 17" to 18" is pretty signficant. So... why do people go to 19" wheels? I think it's all about the current trend toward BLING. The wheel and tire manufacturers love it because they get to sell higher margin products that need to be replaced more often.

Form follows function for me. Thus, I'm quite content with my 17x8" wheels. 18"s are workable. Anything larger than that is pointless in my book until somebody can convince me otherwise.
</soapbox>

So, what to do with the money you saved on wheels and tires? H-Sport sway bars. No brainer. Best mod for the buck. EVEN if you have a sport suspension (as I do), it's a geat upgrade. If you don't have the OEM sport suspension, there's the first place to put some money if you're concerned about performance.

Good luck and thanks for the compliment on my car.

 

darn... i should not have gone with 20" wheels on my 04 tahoe... sorry

 

Heh heh. No worries on a truck. It's all about the aspect ratio...

Lowest I saw on some Porches recently was 35 but that's only because it was a 295mm tire on a 19" rim! You run that kind of aspect ratio on my narrow-body A6 -- what you'd have to for 19" wheels and 235 tires -- and you've got almost no sidewall. On the Porche it worked because you still had a lot of sidewall (295 is a REALLY wide tire!). It also makes a ton of sense on a Porche with their tendency to oversteer and radically staggered wheels.

 

ttt winter size & summer size???

 

I'm running the following...

Winter: 215/55R16 Dunlop Wintersport M3s on 16x7" OEM 2001 Sport six spokers
Summer: 235/45R17 General Exclaim UHPs on 17x8" BBS RKs

Love both setups.