I agree wider tyres at the front would be good so that you can get the power down better and give more grip when cornering not to mention a better feel on initial turn-in, although for all round grip then the same size tyres all round would be best. Having narrower tyres at the back than at the front would only be useful if you're trying to induce lift-off oversteer.
Like I say I only have different sizes on the front and back so I can wear out the 175s before I replace them with proper tyres. The car doesn't seem appreciably different in terms of handling at the moment but I'm sure it'll improve considerably when I get the 195s on the front.
I suspect highpowered RWD cars have wider tyres at the back purely for the purpose of traction, equally wide tyres at the front would give little real benefit (since they're already pretty wide as tyres go) and in fact would probably be detrimental with regards to reduced steering lock. |