Im planning on buying some audi/vw 2 piece splits that are 18x7.5j.

I currently have the standard vrs alloys on with 205/50r17's,does anyone know what size tyres i will need for the splits, would like to run a little stretch as its on coilovers and quite low

Cheers in advance

205s are acceptable with a 7.5J width. Up to 225s will fit a standard Oct with no mods.

 

1. You presently run 205/50s, which gives us a wall height of 205*0.50 or 102.5mm. Increasing from 17 to 18 inch diameter increases wheel diameter by 1 inch, or 25.4 mm.
2. Converting that to a radius means that the wheel radius increases by 12.7mm.
3. We now need to subtract that from the tyre wall height to retain the rolling radius, so 102.5 - 12.7 gives us 89.8mm wall height. 89.8/205 = 0.438, or 43.8%.
4. There is no such thing as a 43.8 aspect ratio tyre, so you want a 45 or 40 aspect ratio in a 205.

 

Hopefuly this is clear enough that you can substitute a new tyre width in (3) if required.

You could have explained that better, thanks ever so much mate, appreciate it

Cheers