My crossflow seven is currently very nicely setup for fast road / B road use on 185/60/14 minilite replicas (Caterham supplied KN I believe) with Yokohama AO21 tyres. The gearing is spot on and the speedo very accurate. Having been flat floored it's also got a pretty optimal 80mm beneath the sump.
i can go longer buy AO21s and they will soon be illegal having swopped front to back to wear them all out. The cheapest most obvious option is to get a set of Toyo R888R in the same size as present but fear these will have to be medium compound because the softs simply seem unavailable.
If I move down to 13" then there don't seem to be any 70 profile options these days and anything less will certainly significantly shorten the gearing and result in speedo overread, never mind result in the need to mess with the ride height.
if I went up to 15" I'm guessing that there may be more tyre options but surely they will add weight and also may need new wing stays?
Any thoughts? Recommendations? Go Toyos? I'm loath to give up grip going to a regular road car tyre...