On the fuby vrs im picking up on thursday it has 16 inch alloys, i quite like the look of the 17 inch octy alloys but have concerns about the speedo not reading correctly. are my concerns justified?

So long as you keep the rolling radius similar (ie increase in wheel size, decrease in tyre profile) there will be negligible change Your speedo will currently overread by up to 10% at the moment, so it's not greatly accurate with the 16"'s on....

Chris

205/40/17 tyres will give you a similar rolling radius.

Some have gone for 215/40/17 but this gives slightly greater radius

I run 215/40/17's and now the speedo is about spot on. GPS reads 30mph, so does the speedo...................Sorted.......................