Redonred81

Could this be.its a 78 silver anniversary,tire pressure sticker on door says 225 70 but original owner claims it came with the 255 GT radials.maybe it was optional?

gbvette62

P225/70R15's were standard, and P255/60R15 GT Radials were optional.

The Tire Pressure Information Label was part of the Federal Certification Label and would have listed the tires originally installed on the car. It's highly unlikely that the tire information could be wrong. The information listed on the labels, is Federally mandated.

A build sheet would show the original tire size, but there may be something else to look for. On 78-79 Corvettes with factory installed 255/60's, the lower front wheel lips should be trimmed back about 6 to 8 inches. This was done to provided a little extra tire clearance.

tomvr

gbvette62 is right. My 78 L82 S/A car was ordered with the optional tires. Front wheel lips were definitely trimmed back quite a bit for clearance. I had the opportunity to compare mine with a standard tire car.

7T1vette

According to the Corvette Black Book, both of those tires were 'optional'. I suspect that the standard tire was a 225R70-15 blackwall. The tire pressure sticker could have been for the blackwall or the white-letter tires. The 255R60-15 tires were almost $200 more for that option!! I'm sure those would have had lower recommended pressures and a different tag.

Apparently, the 255's were not originally ordered on that car.

KapsSA

If your fender is trimmed like this it came with the 255s.

Redonred81

Thanks for input

Redonred81

Thanks for input.

hunt4cleanair

If you've concluded there were two tire options, in addition to the standard P225 blackwall tire, you're math is working nicely.

The article (link follows) was published in the Corvette Enthusiast and describes the introduction of the 1978 Good Year P series tire and the options from 1978-82.

Rebirth of a Class: The P255 Series GT Radial

As GB states, a build sheet would confirm what set of tires were shipped with your 1978 which is expected to sync with the tire pressure label. And as others state, front wheelwell trim will further confirm how the body was prepped for the P series tire.

Hope this helps!