Topic: C3 Tire Specs
in Forum: C3 Handling Components
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I attended our local Cars and Coffee last weekend (known here as Griot's Caffeine and Gasoline) and our favorite subject of C3 tire sizes came up with several folks in attendance.
Everyone seemed to remember things a little differently so I decided to do some research and came up with the following based on information from The Corvette Black Book (2002 Edition), Corvette 1968-1982 Restoration Guide by Richard Prince and an online tire conversion chart on TireRack.com. Note these are the specs on what was stock and optional for C3 Corvettes from the factory, not what might fit based on custom wheels, tires and other modifications.
I actually found the progression of sizes and styles very interesting as the C3 matured.
1968
F70x15 BW - Std. (215/70R15)
F70x15 R/S - Opt. (215/70R15)
F70x15 W/S - Opt. (215/70R15)
1969
F70x15 BW - Std. (215/70R15)
F70x15 R/S - Opt. (215/70R15)
F70x15 W/S - Opt. (215/70R15)
F70x15 R/W/L - Opt. (215/70R15)
1970 thru 1972
F70x15 BW - Std. (215/70R15)
F70x15 W/S - Opt. (215/70R15)
F70x15 R/W/L - Opt. (215/70R15)
1973 thru 1976
GR70x15 BW - Std. (225/70R15)
GR70x15 W/S - Opt. (225/70R15)
GR70x15 R/W/L - Opt. (225/70R15)
1977
GR70x15 BW - Std. (225/70R15)
GR70x15 R/W/L - Opt. (225/70R15)
1978 and 1979
P225/70R15 BW - Std.
P225/70R15 R/W/L - Opt.
P255/60R15 R/W/L - Opt. ***
1980 thru 1982
P225/70R15 BW - Std.
P225/70R15 R/W/L - Opt.
P255/60R15 R/W/L - Opt.
*** "Larger tires necessitated trimming the front and rear lower edges of the front fenders for clearance"
In a nut shell, F70x15's (P215) were the standard for 1968 to 1972. Standard sizes upgraded to GR70x15's (P225) in 1973 when radial tires were introduced. That remained the standard size until 1982 with the P255/60's available as an optional size from 1978 to 1982. Note that P255's required trimming of the front fenders until the front ends were redesigned in 1980.
John Sigmund
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Joel Adams
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When the optional 60 series came out, we got some of these cars in the Chevy dealer where I was working. When we first saw them we thought they screwed up on the body work. The front fender lips were cut back about 1/2 inch into the lip and from the bottom edge up about 1 1/2 feet, maybe less. It took a bit of research to learn the trimming was done on purpose for the 60 series. This is an easy way to tell if the cars came from the factory with 60s. Some times the tires will fit without any trimming. I have 60 series on my 75 with no problems. Others will rub if not trimmed. Luck of the draw.
I agree with you on the hit or miss (no pun intended). I've seen a lot of 73 to 79 cars with 255-60's on, some were obviously trimmed, some were not. I think it would be great if someone could supply some pics of a factory trimmed 78-79 car, any body got one we could see ?? Send pics to my email address if you cannot post and I will add them to this thread. I can also add some shots of my untrimmed '73 for comparison.
John Sigmund
valkman57@sbcglobal.net
NCRS Member 61302
NW NCRS Chapter Member
Duct tape is the new Black !!
The C3 rims will not fit a C6 due to brake clearance. But your question was will the C6 fit the C3. The newer rim has more offset and is wider. Part of the answer depends on what tire you put on the rim, and if your car has trimmed wheel arches. By the way that was only done on the front.
I called Tire Rack trying to get rim and tire specs and the guy acted stupid. He said he did not have the info. I told him I just want the rim and tire specs. He would not even give me the bolt pattern size. I know they have this info, I'm guessing he was just lazy.
If you can get a tire store to talk you need bolt pattern, offset positive/negative and distance, rim width, and tire diameters. It will take a bit more research. A dealer will usually only go by part number.
The problem is still not completely answered until you try them on the car.
Has anyone here given it a try? I think one of our members did this but I don't really know.
|UPDATED|6/14/2015 2:01:50 PM (AZT)|/UPDATED|
|UPDATED|6/14/2015 2:01:50 PM (AZT)|/UPDATED|
It wont' change the alignment per say.
If the overall diameter and center position of the wheel is the same, it won't affect it at all.
If either of these vary, the alignment will show okay on a machine, but some of the angles won't interact with the road the same way, and may have an affect.
John,
Good info.
Thanks.
Good info.
Thanks.
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"It Takes A Little Longer To Do It Right"
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Adams' Apple said:
Joel, who is this "Kstyer" guy?
ebo|UPDATED|7/20/2015 1:53:23 PM (AZT)|/UPDATED|
eboin Forum: C3 Handling Components
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