I assume that when Audi changed from 205/60 x 15 on the early analog dash UR they recalibrated the speedo for the smaller diameter tyres ? When I get my UR back on the road I will be fiting some V8 1 piece BBS wheels that are 16 inch so was thinking of 225/50 x 16 tyres.

My problem with an early car is that in using 215/50 x 15 tyres these are almost 5% smaller diameter where as 225/50 on a 16 is just 0.7 % larger. Using 225/50 on a 15 is only 3.3% smaller so a bit closer to the original 205/60 diameter. I think it depends on make of tyre as to if it tramlines, back in the 90's I ran 225/50 Fulda's and at the time these were OK.

One interesting comment on modern(ish) cars I recently convinced my brother to put winter tyres/wheels on his X type AWD which was fitted with 225/40 x18 on 8J (sport premium spec) we used 16 inch 7J rims from a lower spec X type with 205/55 tyres, all I can say is that what a difference, the car feels much better still handles as well as an X type can and absolutely no tramlining so I guess we are all becoming victims of fashion with the increasing use of super low profiles.

We've got 205/55/15 Toyo T1Rs on ours... 225/50/15's caught on the rear arches when fully loaded and the suspension compressed, and when we needed 215's they weren't available.

Toyo do a 215/50 15:

http://www.demon-tweeks.co.uk/Produc...FUfkwgodOaAAOg

Aren't they track day tyres?

The write up says:

"The Proxes R888 is a sophisticated track day tyre, but is also fully road legal - making it suitable for high performance road driving, or driving back home after a trackday. The Proxes R888 boasts an outstanding handling compound which delivers optimum results in the dry and wet".

quattros can be deceptively lively little numbers in the wet, especially standing water on motorways... I can't imagine those helping the situation..!!!!:ihih:

Agreed

I just don't like the look of those R888 road legal track day Proxes.

This little gizmo is good to compare

http://tire-size-conversion.com/tire-size-calculator/

It even gives you a visualisation of the 2 tyres to compare.

Are you interested in two tyres? I have two 215/50 Dunlop's with 6-7mm of thread. Very good condition and low miles on them.

http://www.bildites.lv/images/g58cfd7mhx2jwhnkqxn.jpg

Not cheap new, holy sheet!:eek:

http://shop.atseuromaster.co.uk/tyre...Z-0-1-4I5-1789

Cheaper

http://www.clickontyres.co.uk/premiu...sp_sport_9000z

I got mine from camskill, £495 including delivery iirc.