After much searching, I finally have tracked down a suitable set of tyres for my unusual sized wheels. The fronts are 18" x 11" which equate to 285 35 18 and which were not too hard to find but the colossal rears are 18" x 13". I currently have a pair of Michelin 345 35 18 which fit fit but which Michelin stopped producing around 15 years ago so they're not ideal. They are hardly used and were stored well so are in decent condition and I will be happy with them for road use but when I am pushing on, I wouldn't be too confident. These are the same wheel sizes as a Jaguar XJ220 and tyres are made specifically for them by Bridgestone at a mere £4k+ per set so I chose to look elsewhere!
It turns out that these sized wheels are also used on a Dodge Viper and whilst they are not a UK supplied car so the tyres are not generally available through the normal sources, they can be found in the US & mainland Europe. The Viper uses 335 30 18 which are a smaller rolling circumference to mine but at least they will fit and I will be using a GPS wireless speedometer for speeds anyway as mine only has a KPH read out so I'm not too fussed about that discrepancy.
I found a guy who has just bought a Viper which came with an unused second set of four P Zero Rossos and which he wanted rid of, so a decent saving for me.
The car goes away for the new fuel tank next week and when it returns I need to fit the new bonnet clips, wheel arch liners, change the wheel, apply the decals and then it should be almost ready to go
