I currently have 14 inch wheels on my car, with 165/55-R14 tyres which are a bit stretched as the rims are quite wide, this looks like it has been done to avoid sticking out from the arches. I have now got some arch extensions, so can fit some wider tyres, but I was wondering what sizes people have been able to run successfully without hitting the arches? (My extensions stick on to the lip and add ~15mm)

From looking at the car I recon I can get away with 195/55-R14 on the back (5.8% bigger radially than current tyres) but if I could fit 195/60-R14 (8.9% bigger) it would also sort out my speedo over-reading problem too...

So what are you all running??? (interested in any rim/tyre combo for completeness)

mine has 185/55/14 on and they didn't touch the arches when I first got the car. Since then I have altered the front suspension to bring the tyres in a bit from sticking out 35mm beyond the arches resulting in an advisory at its last MOT. They now stick out about 10mm but don't contact the front arches. On the rear I have changed to an MGF setup which has very large hubs triangular shaped which wiped off the balance weights from the rim so fettling with an angle grinder to get clearance has sorted that out but as the MGF has 15 inch wheels my speedo will be way off so I will see if I can live with it. The rears don't foul the arches either.
Peter.

Not sure if this is of any help

http://www.brspecialtuning.co.uk/Tyre%2 ... ulator.htm

Been playing with one similar to that - although rather amusingly they give slightly different results to each other (although within a mm or so)

Do you know which tyres they are on the 15 inch rims? A quick google suggests that there were a variety of different tyres fitted to MGFs...

The MGF 15 inch rims would normally have 205/50/15 on the rear and 185/55/15 on the front. Looking at the calculator it would appear that I will be reading 4 percent faster than I am actually going (28 instead of 30 and 67 instead of 70. I can live with that, it may save my license!)
Peter.

hi
I have 185/50-R14 on my car and they miss the arches but do stick out from the arches. I have now got some arch extensions on the front
i used this http://tireconvert.com/ and its saying my speedo will be out by 7.75%

Speedometer reading:
60 mph
Actual speed:
55.35 mph

-7.75 % slower

this is a bit to much
so i have got this from jaycars CORRECTOR SPEEDO MODULE


http://www.jaycar.co.uk/search?text=spe ... 90c71d978c

This module alters the digital speedometer signal up or down from 0% to 99% of the original signal. not the mechanical one
I do not no if this works yet as my car is of the road I hope to find out soon