Tire sizes for a C3

[Santovenia]

Any one have any idea what the maximum tire size you could fit on a 1975 vette
is? I was thinking maybe i could put 275/45/18's on the rear and maybe 255/50/18's on the front. But the www.tires.com doesn't recommend anything larger than a 255.

 

[wishuwerehere82]

You can put 275's on the back, but from my personal experience it will compromise handling and ride qualities.

If you have the 275's on the rear with either 225's or 255's on the front the back end will be raised. The end effect is a rocking effect the causes the rear end to bounce a lot more than if the vehicle is level. This effect is quite noticable on twisty roads and causes a loss of control on heavy cornering.
I had 225's on the front and 275's on the rear of my '82 with new springs and shocks, and I would literally be bounced out of the drivers seat on rises in the road.
I switched to 255/60/R15 Goodyear Eagle GT2's on all 4 wheels last Spring and feel the ride is drastically better and more controlable than with the 275's. The 255's actually have better traction too.
My .02

 

[70 LS1]

245/45/17 fronts
275/40/18 rears

 

[cool80]

Nice 70!!!!!!!

cool80

 

[lnirenberg]

I have no idea about rear clearance and as my car is street driven in season whenever possible and not autocrossed or any other kind of competition, I wimped out and went with 235/60-16s. I am very pleased as just about any 16/17/18" tire is better than anything available @ 15". If the 275/45-18s don't rub on the body at the bottom of suspension travel they are actually 1/4" smaller in diameter than 255/50-18s which means that should have a minimal effect on the relative ride heights of the front and rear. The rear size you are considering will make the speedometer understate speed by about 1 mph @ 65 mph, no biggie there.