Forget 15" wheels as you'll not get the front ones on over your Brembo's.

Regards,

Ian M K

 

I have attended a number of track days this year and the first lesson learnt was 5 laps round Donnington = knackered road tyres. I bought myself a set of Comp MO's with part worn slicks and I was amazed at the grip levels, I have adjustable LEDA which I set at around 20 all round, and I also lower the car for track days, this with Brembo brakes seems to do the trick. I do however eat up tyres and I was after some advice.
I have taken the now shot slicks off of my Comp MO's and put a set of SO2's, which I will use for road and wet track days. I have a part (Non road legal) set of S02's on 16" standard wheels which I plan to leave on for intermediates, or when the weather is changeable so not to destroy the 17" S02's. What I want to do next is get a set of wheels which I will use for slicks, I plan to get an old set of 16" wheels but I wondered about 15". The 15" option will be cheaper but I wondered about roll radius's etc. Any help would be most welcome.

 

The roll radius isnt that much of an issue if you get the rigth size slicks as they should be about the same size as a standard road tyre. Slicks are measured differently though and you will need to be careful about them rubbing the suspension/wings. It seems that people with 22 or 21 width slicks are getting this problem. I have had 18 width slicks which have not been a problem ideally I would like to get something a little wider possibly a 20 but these seem a little harder to come by. The second figure on Slick's is the diameter of the tyre if you work out on a standard tyre these come out at about 611 mm so a 60 or 62 diameter wheel will be about right. The only reason most people worry about rolling radius is to keep the Speedo accurate and as on a track day that doesnt really matter you could put a slightly smaller tyre on and this way you would get better acceleration.

Darren

 

Darren\Ian,

Cheers.

I don't know what profile the slicks were on 17" wheels they were but they were not what I would call low profile tyres. I took the car out at Weathersfield for load of laps and noticed a slight rubbing noise when cornering. I didn't worry about it to much until I put my normal road tyres back on and I noticed that I rubbed away sections of the plastic guard in the wheel arches. LEDA spent ages setting the car up and I am reluctant to change them as the car handles like a dream. I have left the guards as they are as I would have thought that this may be a very expensive fix. The car is fine on the road now with the 17's and SO2's but I want to get 16" wheels with low profile slicks.