I've just bought a set of polished FPV copy wheels for my NL Fairlane, and I need some help with tyre sizes for it.

The wheels are 18x8 and I want to run 2 different tyre sizes front to back.

A bit of background info, the car is lowered and is running 225/50 16's at the moment, when I bought it they were rubbing on the guards going over bigger bumps at the front and pulling the guard lips down, so I had them rolled and clearance has not been an issue since.

I'm thinking of running either a 225, which I know will more than likely provide plenty of clearance, or maybe a 235, but clearance is my concern here, I don't want to go back to having the tyres rub on the guards. More than likely a 235 and hope it won't rub, it should be ok.

On the back I want to run 255's.

Can anyone give me a tyre size and aspect ratio for both a 255 18 rear and a 235 18 front that will match or come close to the rolling diameter of the 225/50/16's. I think when the car was new it used a higher profile than the 225/50/16's as the spare is a 215/60/16, which may have something to do with the speedo reading a fair bit lower than it should. 107 on the speedo when its really doing 100.

Cheers.

255/35/18 and 225/40/18's would be the closest.

Thanks