Help at Spa/Ring 2010

[shimmy]

Originally Posted by s.mac

why would you ?

i thought about from a cost point of view but didnt see much of a saving in the tyres

Originally Posted by mattCSLnut

Seems there is a considerable £££ difference between 18" rubber and 19" rubber. Genuine M3 18' can be had for peanuts and 18" R888 for around £600 as oppose to £1200 ish for 19" R888. Cups about the same in 19" CSL sizes.

well my original thought was that as i have a stack of 19 inch Cups i might as well get new lighter stiffer 19 inch rims. But the more i look and looking at some recommendations like Thorney on the 18 inch Rays i reckon i can get the rims about £400 cheaper, 1kg per corner lighter and stiffer on 18 inch rims over 19 inch rims and the Cup tyres (dont forget they will be 265 all round) are adding up to about £100+ cheaper a set. so currently if they are availabel in time i will be going 18 inch - but nothing for certain

Originally Posted by s.mac

R888 aren't meant to be that good on a CSL, so little difference between the 18 / 19 cups

correct

Originally Posted by mattCSLnut

I'm willing to experiment and find out for myself They can't be completely useless. I've experienced "Flatout's" Z4M Coupe (with 18" R888s) that beged to differ and a m8 of mine runs a Porker 928 GT (the Manual one) Race car with a set of 18" R888, with great success.

I have seen R888 on road M3s and GT3s and the main difeences seem to be that;

1.R888 are better in the standing wet stuff
2.R888 are only very slightly cheaper now
3. R888 do overheat quicker on road cars
4. Cups are generally slightly better and grippier in dry conditions

Item 3 is important. R888 on a heavy car like the M3/CSL at over 1400kg + driver seem to go off (overheat) after say 3-4 hot laps whereas Cups take a few laps more. Overheating means your grip goes away and the tyres loose lifespan. Now this can be managed but 3-4 laps isnt very many!

R888 seem to work much better on slightly lighter cars, not sure how heavy the Z4M is but race cars tend to be circa 1100Kg max