C2 Spare Tire Fit

[Dave B.]

I know there have been many previous postings regarding the fit of repro tires in the spare tire tub - I'm trying to get the latest info and opinions on my problem. I recently purchased my first C2 (65) which happend to not have a spare installed. I located a correct wheel and decided to purchase a repro Firestone 7.75x15 bias ply tire since it would be close to correct for any future judging. I knew there was an issue with radials fitting the tub but at the time I had not seached the archives sufficiently to learn that many repro bias ply tires would not fit either.

Previous postings indicate that the repro Firestones and Goodyears will not fit. Coker tire's website shows B.F Goodrich dimensions virtually the same as Firestone. Does anyone know of any current production repros that will fit the original tub? I recall one post that indicated some manufacturing procedure on new tires causes a increased tire diameter compared to the original tires. Is my only choice to search for an old non dot tire?

Thanks in advance for any help and guidance.

Dave Brown

[Douglas L.]

Re: C2 Spare Tire Fit

Dave,

Just went through this exercise. Newer 7.75 x 15 Firestone would not fit with more than 15 - 18 lbs. of pressure. And the fit was "very" tight. Went back to older DOT 8.25 x 15 - fit no problem even though it's wider.

Interesting though, in another car I have a Coker 7.75 x 15 bought in 1989 - fits no problem.

I'm not sure what the answer it, but I do not think it's a DOT vs non-DOT thing.

[Edward S.]

Re: C2 Spare Tire Fit

When I bought my 65 it had goldlines on it, dot Coker ordered Goodrich, which at the first show I went to I found out that Goodrich did not supply Corvette in 1965. I bought Goodyear Goldlines which required longer hardware, I got tired of cleaning that narrow gold wall and then bought Firestone DeLuxe Champions DOT for judging and went back to original hardware without a problem. This whole thing could revert back to all tires being made not being exactly the same. Good luck.

[Larry M.]

Re: C2 Spare Tire Fit

I know there have been many previous postings regarding the fit of repro tires in the spare tire tub - I'm trying to get the latest info and opinions on my problem. I recently purchased my first C2 (65) which happend to not have a spare installed. I located a correct wheel and decided to purchase a repro Firestone 7.75x15 bias ply tire since it would be close to correct for any future judging. I knew there was an issue with radials fitting the tub but at the time I had not seached the archives sufficiently to learn that many repro bias ply tires would not fit either.

Previous postings indicate that the repro Firestones and Goodyears will not fit. Coker tire's website shows B.F Goodrich dimensions virtually the same as Firestone. Does anyone know of any current production repros that will fit the original tub? I recall one post that indicated some manufacturing procedure on new tires causes a increased tire diameter compared to the original tires. Is my only choice to search for an old non dot tire?

Thanks in advance for any help and guidance.

Dave Brown

Dave:

A couple of suggestions:

First, I would buy a cloth tape measure and accurately measure the inside circumference of YOUR tire tub. This can vary depending on whether it is original or a later reproduction/service replacement. Another method is to run masking tape all around in the inside and then remove and measure the tape. Once you have the exact inside circumference, divide by 3.14 to get the inside diameter.

Most of the current reproduction tire manufacturers provide both a tire circumference and a tire diameter for their tires. You can then determine what fits.

Second, you can have a tire thread shaved to slightly reduce the circumference or diameter. I'm not certain who does this anymore, but there should be someone in your area that can provide this service. Check around with a few local tire suppliers. Also, if you are close to a racetrack, there should be someone who does this for the racers.

In a previous TDB post (June 21, 2006), Wayne Midkiff stated that "C2 tubs can accept up to 88 inch circumference tire. If larger than this, they will jam in the tub. Examples of those that fit are: original Uniroyal whitewall 7.75 (86.75" circ), original Firestone Goldline Supersport 7.75 (86.375" circ), and reproduction Firestone Goldline 7.75 (85.875" circ)."

A circumference of 88 inches equals a diameter of 28.0 inches.

On my 1967 car, the (original) tire tub inside diameter is approximately 27.875 inches. I have no problems with fit on 7.75 Firestone Deluxe Champion whitewall DOT tire from 1968 time period (27.0 inches diameter) or 7.75 Firestone Deluxe Champion Redline reproduction tire from 1995 time period.

The current reproduction and service replacement tire carriers seem to be slightly larger in diameter/circumference than the originals. Measure YOUR tub and then check current manufacturer's tire data before ordering.

These suggestions are for tire diameter/circumference only. Tire cross-sectional width is another consideration. However, there are different length bolts for the tire tub/lid that are currently available to accomodate the larger cross-section or width of the redline, goldline and radial tires. Hope this helps.

Larry

[Wayne M.]

Re: C2 Spare Tire Fit

.
....In a previous TDB post (June 21, 2006), Wayne Midkiff stated that "C2 tubs can accept up to 88 inch circumference tire. If larger than this, they will jam in the tub. Examples of those that fit are: original Uniroyal whitewall 7.75 (86.75" circ), original Firestone Goldline Supersport 7.75 (86.375" circ), and reproduction Firestone Goldline 7.75 (85.875" circ)."

A circumference of 88 inches equals a diameter of 28.0 inches.
Larry

Larry, others -- I can add 2 points since I posted that info. The problem tire (original - but not on a Corvette - 7.75 by 15 Firestone Dual [something].., that was almost 89" circumference, and wouldn't fit) was solved by soaking a rag with Armor-All and wiping the contact surface circumference on the original tub, as well as the tread surface of the tire itself. With 22 lbs pressure, it still hangs up in the tub when you drop the lid, but with a yank you can at least get it out. So that might be a solution for marginally oversize tires.

Since my earlier post, I've bought a set of recent (3-4 years ago) repro 7.75 by 15 Firestone Deluxe Champ white walls, and yes, even un-mounted the fit is snug -- so I don't know how they'll fit with air in them. So maybe the later repops are of larger diameter --- if so, too bad.