GR8DAIN

My '71 has 225/70-15 tires. Is that the original size?

MidShark

That is the modern day equivilant. Your car came with F70x15 tires.

Rich

wfo76

215/70-15 is the modern equivalent

The original F70-15s were 26.92 inches on diameter and that is the spec of the 215

The 225/70-15 are 27.4 inches and are wider and about a 1/2 inch taller than stock

215/70s are harder to find so most go with the 225 but they are larger than original

The 225/70 is the correct size for GR70-15 used 73-77 but big for the 68-72

bashcraft

I have 225/70-15 BFG's on my '69. After mounted they actually measure 27" tall rather than 27.4". Next time I'm going with 235/70-15.

Jim71Vette

But... will a 235/70-15 fit in the spare tire carrier?

bashcraft

I don't know, but I have a new 225/70 for the spare which I will keep. If I would need to use it on the back, I'll just make not to drive it anymore than necessary.