phiberoptik26k

i was just reading another post in the forum and it said that there can be a slight problem in changing tire/rim combos on a TT with the speedometer. Here is an excerpt

"In the mean time, I received the info I was looking for from Tirerack.com. They said they recently tested many tire/rim combos on the TT and the widest tire the car can fit without strut interference is 235/40 (on a 17" wheel). I'm not too happy about that because this will mean a circumference change from the stock 78.5 inches to 76.7 inches (over .5 inch decrease in the Diameter) giving some relatively minor odometer/speedometer problems as well as a smaller looking tire in the wheel well. Not sure what size tire I will run just yet...I have at least a month until my Zender Monza's arrive from Germany."


is this true? if so can you recalebrate your speedometer for the newer size rim? i'm thinking about going from 17" to 18" possibly a 19"

TTschwing

As rim size goes up, sidewall height is reduced retaining approximately the same rolling diameter. It's classically called the +1 or +2 ocncept.

All you need to know is here....<ul><li><a href="http://www.chris-longhurst.com/carbibles/tyre_bible.html">http://www.chris-longhurst.com/carbibles/tyre_bible.html</a</li></ul>

phiberoptik26k

what do you guys make of this info?

TTschwing

That info is accurate and Edgeracing is a reputable supplier of wheels and tires. I bought my 18" set-up from them....As long as all 4 tires have approximately the same rolling diameter and it's close to the original 225x45x17 you're fine. MANY people here have staggered setups, 18" and 19" wheels in different widths etc. Don't sweat it. Use the calculator on the link I provided and get specs on the tires you are looking at for more precise info. You're over analyzing this..

phiberoptik26k

thanks. i probably am over analyzing...