C3: Wheel rims

[Rob M.]

Hi all,

Today I wanted to get correct tires on my '69 car but unfortunately I found out it had 8" wide rims (instead of the original 7" types). Does anyone has a clue where I could locate a set of original rims for my early '69 car (build date sept. 68)?

thanks all for your help,
Rob.

[Terry M.]

Re: C3: Wheel rims

Rob,

1969 had 8-inch wide rims. 1968 had 7-inch wide rims. I don't think early 1969 was different.

[Rob M.]

Re: C3: Wheel rims

But the tires are less wide than 8", and would be smaller than the rim? Is this indeed the case?

greetings,
Rob.

[Steven C.]

Re: C3: Wheel rims

Rob:

I believe '68 through early 70's used F or G70-15, even though '68 had 7" rims and '69 up had 8" rims.

You are correct in saying that the tread width is less than the rim width (the tread width was maybe 6-7 inches) - this is entirely OK, the air does the work. The "correct" replacement size is apparently 215-70-15, which is about 8.5" of tread width.

Rims and tires can be very forgiving, for both narrower and wider tread widths.

Steve

[Terry M.]

Re: C3: Wheel rims

Yes -- F-70x15 for 1968-1972

[Duke W.]

Re: C3: Wheel rims

The OE '68-'72 tire was F70-15, which is about 775 revs/mile, which is the same as 215/70R-15, but the Corvette speedo gearing was originally set up for the 6.70-15 and did not change - at least with manuals, so the speedos will typically read a couple percent high. Seven inch wide wheels were a '68-only feature. All '69-'82 OE wheels were 8" wide. Beginning in 1973 the base tire was 225/70R-15 and 255/60R-15s were added in '78 as optional equipment and were standard on some later models.

The 225/70R-15 has the same revs per mile - 760 - as 6.70-15s and there is plenty of wheel width and fenderwell clearance space for either of these sizes under C3s, but I recommend 225/70R-15s for all C3s.

"Tread width" is a function tire width, profile, and shoulder design, and radial tires have more rounded shoulders than bias ply tires. Tread width will vary somewhat among manufacturers/models within a given size designation. What's important to matching wheel width to tire size is OVERALL SECTION WIDTH, and section width changes about 40 percent of wheel width variation from the "design" wheel width. The range of acceptable wheel width is about +/- one inch from design width, but is specified for each tire size. It's an industry standard. A 215/70R-15 has about 8.5" SECTION WIDTH, NOT TREAD WIDTH, on the design 6.5" wheel. One an 8" wheel the section will measure about 9.2" and a 225/70 will be about 9.6".

If you want to educate yourself on tires you will find a very thorough and comprehesive discussion of C2 and C3 replacement tires (for driving, not judging) including every number you can imagine - correctly listed - and the best currently available replacements that are suitable for a sports car in the spring and summer issues of The Corvette Restorer.

Duke

[Duke W.]

That's the Spring and summer, 2003 issues... *NM*

[Rob M.]

Re: C3: Wheel rims

Ok, I have a set of F70-15 RWL Firestone Wide Oval tires and the 8" rims. Is this an acceptable, safe combination or should I try to swap the tires for wider versions? The thread width is app. 7" (185mm ?).

thanks for all your help,
Rob.

[Joe L.]

Re: C3: Wheel rims

Rob-----

It's not only safe and acceptable, it's the exact combination of tire and wheel that was used for 1969.

The raised white letter tires were also an optional tire sidewall configuration available for 1969.

The Firestone Wide Oval tires available in reproduction today, though, are not exactly the same tire used for 68-72 Corvettes originally equipped with Firestone tires. The reproductions are a fiberglass belted tire. Although some cars of the period did use the belted version of the Firestone Wide Oval, Corvettes were not among them. The Corvette Wide Ovals were a bias ply, nylon cord tire without any belts.

While the Firestone reproduction tires are not 100% correct for Corvettes, they are, functionally, a better tire than the original Corvette tires. They will ride a bit harder than the original tires, but they'll wear a lot better.

[Duke W.]

Re: C3: Wheel rims

It depends on your objectives and what you mean by "acceptable and safe". If you are looking for a period look, the tires you mention are close and should meet minimum DOT performance standards (which have not been updated since about the time your car was built).

If you are looking for the best and safest "driving tires", the available modern 215/70ZR-15 97W and 225/70R-15 100V radials will provide the best ride and handling with the built-in safety of a modern spiral-wrapped nylon cap belt.

If you are concerned about judging deductions, you'll have to refer to your year JG to determine point deductions for the various tire installations.

Duke

[Mark #28455]

RWL tires after Sept 1969

The RWL tires were a late 1969 option, starting somewhere around Sept 1969, so they would NOT be appropriate for an early car.
Sorry
Mark

[Rob M.]

Re: RWL tires after Sept 1969

Ok, thanks all for your responses. I'll get the tires mounted (allthough they are only for later '69 cars) since I do like the looks so much. Next step: take the car to LeMans for a nice road trip and spectacular races... (organized by our fellow UK chapter).

Corvette Rules!!!

greetings,
Rob.

[Rob M.]

Re: RWL tires after Sept 1969

I had the car back yesterday from the garage and it really looks terrific with the new tires. thanks all for your comments and remarks!!!

Photo's will be posted later...

greetings,
Rob.