custom Tyres and wheels 1/6th

Hi all, new to this forum so i bet ive listed this in the wrong area. but ill carry on anyway.

I am currently working to make a scale model of a Triumph GT6 in 1/6th scale and ive
hit a wall when it came to the tyres. I have been looking on the internet to
find/research either premade or a method of making them and a process and materials
that will fulfil my requirements. I think im going to find the tyres the hardest to
get the right products, the rims will be a still a challenge but not too bad.
Sizes are roughtly 58mm rim diameter, 92mm outer diameter, and about 20mm wide.

If anyone can help or advise me on what process or product is best which i can use in a
mould (which i think will be best) and will dry/set black and very similar to a tyre,
and show similar properties to a fully size tyre. I would like to make it hollow and
no just a solid lump.

Source: http://cs.scaleautomag.com/SCACS/forums/thread/975594.aspx

Art Cross Geoff Crossley Chuck Daigh