i currently have 4 x yokohama slicks on my ADR which have hardly even turned a wheel. there is no wear at all to tyre surface,but they have been stood for near 10 years and show signs of graining on side walls!
i have a chance to buy another 6 wheels (they are rare centerlocking items specifically for this car) 4 are a full set of wets and the other 2 are rears and have soft sprint slick on them.
i dont have the funds to buy 2 more new front wheels and put another pair of soft slicks on them for sprinting as well as another full set of circuit slicks on my current wheels so;
1.how robust are slick tyres? and would you guys replace the 4 currently on the car?
2.is there any way i could compete in sprints (sports libre) with the 2x rears with softer yoko slicks (if i buy them) and circuit slicks on the front? so i dont need 3x full sets of wheels!
3.how exactly are they sized? my rears say 220 width but are close to 300mm when i measured them?
4.how do radial and crossplys differ and which would be best suited?
cheers!

10 year old tyres will be rock hard even if stored off car at a constant cool temperature.

Best perhaps to forget the wheels and buy 4 brand new slicks --- even 2 year old slicks are well past their best.


The biggest single difference between xply and radial circuit tyres is radials work best with more negative camber than xplys.

[Edited on 27/7/13 by britishtrident]

If your current tyres are 10 years old they are probably no good.

This is based on my experience with formula renault tyres but circuit slicks won't heat up quick enough for sprinting and they don't respond we'll to hard use before they are warm. They take 2-3 laps to warm through and if you hammer them before they are warm they just scrub the surface.

Have you tried contacting any race teams to get used slicks? I get mine from a formula Renault team as they have to pay for disposal so me taking them for nothing is preferable.

Slick tyres seem to be measured from bead to bead rather than across the tread so the tread is wider than the width measurement.

Agreed. Yours will be as good as scrap. Unless pushed for space id hang on to them for rolling road and shake down use maybe. A new set of those yokos aren't 'that' expensive.

My tyres ( Avon ff2000 xplys) after 2-3yrs are scrap. Night and day difference with new ones - like 2.5s a lap at brands for me!

I suspect your tyres are the same as used by the 750 formula and sports 2000 (Sports1000 was a 750mc bike engine equivalent to 750 formula as I'm sure you are aware). For info, in the last 5 yrs I believe yoko have stopped supplying the xply version of this tyre and all have been forced onto radials.