1968Cutlassfallbrook

Hello,

I have a factory drum brake car but I have been thinking of swapping to front disc to help with stopping. The question I have is will the factory 14 inch rally wheels work with disc brakes as I'm thinking of finding a set of 14's or do they have to be 15 inch wheels? Also my car tires were a factory 7.75 14 and it currently has 235/60/15 what would be the correct tire to get the speedo to be correct?

Yellowstatue

The factory rallyes fit disc brakes and as for the speedo, usually you pick the tire size you want and then get the correct speedo gear to make your speedo correct... each gear is coloured for the number of teeth that it has...there are a bunch of NOS gears on e-bay right now...

1968Cutlassfallbrook

What size of rotors fit with the 14 inch rally as I'll be buying aftermarket I believe. Thanks

John

joe_padavano

If by "rally" you mean Super Stock II or III wheels, yes they clear the FACTORY 10.75" disc brakes and calipers. All bets are off with aftermarket brake kits. The Super Stock I wheels come in drum-only and disc brake versions. The former will NOT clear any disc brakes. Stock steel wheels on a 1968 drum brake car are likely to be drum-only wheels and again will not clear. The backside contour of these wheels interferes with the caliper.

The original 7.75-14 tires were just over 27" in diameter. 235/70-14s would be just about the same O.D. if you could find them, but unfortunately no one makes them anymore (except maybe Coker, but expect to shell out very large dollars). 225/75-14s are about 27.25" in diameter and probably more readily available. The extra 0.25" of diameter would result in about your speedo reading about 1% slow. Your 235/60-15s are only 26.1" in diameter and are making your speedo read fast.