Looking at a different set of alloys, I wanted to keep the same profile but change the offset, however the set I want are minimum 8J. So my question is to keep the rolling radius the same and keep a nice crisp clean tyre without stretch or balloon, what profile would people recommend? The maths works out at about 225/35R17 but this seems the be really not viable :/

Cheers!

http://www.kouki.co.uk/utilities/visual-tyre-size-calculator

 

Only approximate. Tyre Brand dependent.

as in you can get 205/40 R17 Pirelli that side by with Dunlop 205/40 R17 are physically bigger, (greater Total Diameter.)

I have 215/40 R 17 that are small than the 205/40 R Pirelli.

 

http://alloywheels.com

I don't know much about offset, but increasing the width of the wheel can cause complications with clearance.

Legally, your tyres can't exceed the body width. But wider wheels may foul on the bodywork.

A rough guide is to decrease the profile for every increase in wheel size, but the profile is as a percentage of the width, so if you increase the width, but keep the same wheel size, you'd also have to decrease the profile (logically).

Your avatar says a polo - is it for that? I think George's link to that. Site will tell you whether different fitments will fit your car.

The is a Thread on this Forum showing the various Wheels & Sizes fitted to Fabias.

With pictures

 

The 'Audi A1 Competition Line' comes fitted with 18" X 7.5J, with 225/35 R 18" instead of the 215/40 R 17's fitted to other A1's.

 

The 18" x 7.5 fit ok in the arches of Fabias with the 225's fitted.

No idea about Polo's if they are for fitting to one, the 8" or the suitable ET.