I reacently read about a road test of a 57 Corvette with Fuel Injection. The Magizine ( Road & track I believe) said it had a top speed of 132 MPH. I understand that the 427 C2 had a top speed of about 140 plus MPH. My question is did Chevrolet put special speed rated ties on these cars like today's Corvettes or were the tires the same as a regular passanger car?
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Re: C1 & C2 tire rating
Walter-------
In those days the only special tires were racing tires. Those tires were not really suitable for use on the road and GM never installed them on ANY PRODUCTION vehicle. The tires used on Corvettes were essentially the same as those used on other passenger cars.In Appreciation of John Hinckley -
Re: C1 & C2 tire rating
There were no tire speed ratings in that era. Speed ratings started in Europe sometime in the sixties. The first speed rated tires I ever installed on my SWC was a set of 205HR-15 Pirelli CN72s in 1968 to replace the non-speed rated 6.70-15 Michelin X set installed in 1964.
The first model year speed rated tires were installed on production Corvettes was 1984.
Specialized racing tires of that era were not speed rated, but they were generally low angle nylon cord (which made for very stiff sidewalls) with relatively hard compounds and were actually pretty robust. They were probably closer in design to truck tires, and didn't have much more grip than passenger car tires.
Racing tire technology really took off beginning in the mid sixties as they became wider with softer, gripier tread compounds with little more than siping, and the first road racing slicks showed up in the early seventies after slicks were already in drag racing use.
DukeComment
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Re: C1 & C2 tire rating
I recall Sportsman class 1/4 mile oval racing cars in 1962 running on 4 slick tread tires on asphalt tracks in the east. I was stationed at Ft. Belvoir, Va. And toured the tracks around VA. And MD., both drag and oval on weekends.
Stu FoxComment
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Re: C1 & C2 tire rating
Back in the late '50s early '60s the best tire for drag racers were Atlas Bucrons. You could only get them at Standard gas stations. They were sticky as hell which was great for racing but you'd be lucky to get 10,000 miles out of them.Comment
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Re: C1 & C2 tire rating
Mark -
I was raised on Woodward Avenue in the 50's and 60's, and in those wide-open days (and nights), a pair of Bucrons was good for one weekend; I'd buy a pair of 8.20-15's on Thursday night for $18.00, and they were showing cord by Sunday night.
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Re: C1 & C2 tire rating
So was it safe to say that the tires were safe or unsafe on new Corvettes ? I rember once seeing a test how tires started to change there shape in a negitive way at speed over 100MPH. I remember Caroll Shelby putting blue Dot tires on all 65 GT 350 Mustangs. I think that was some kind of speed rated tire.Comment
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Re: C1 & C2 tire rating
The tires you refer to for the 1957 Corvette road test in the Road & Track issue was in all likelihood Firestone Super Sports. This tire was first used at Daytona and Sebring in 1956. From a technical standpoint it was in fact offered by Chevrolet as: "TIRES - 7.10/7.60 x 15 racing tires and tubes (available in sets of 5, 8 or 12); relieved wheel housings." This was part of the option package first offered by Chevrolet in 1956 and carried over in part to 1957. Just how many people were aware of these options at the time is a matter of conjecture.Comment
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Re: C1 & C2 tire rating
John H.;
I raced 59 through 61 with a 57 post Chevy in sanctioned and unsanctioned drag racing. We were allowed two sizes over in sanctioned (Great Lakes Dragway B/S) events so we ran Goodyear Double Eagles (8.50 x 14's ??). We would try to find used tires at tire stores and gas stations, and attempt to further break them in to near slick (no tread left) condition. We would make it near a full season on one set. For unsanctioned racing (Kilbourne Road WI/IL state line), we'd change to M & H slicks and my buddy would drive (better power shifter) to take home the $50.00 a pop match race. We'd split the take from the commandoes, who couldn't/wouldn't run at the track, and set out for the nearest Sunoco station to tank up for next week.
You must have been just showin off on Woodward Avenue doing burnout contests or something to go through to the cords so quick, Ha !
Stu FoxComment
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Re: C1 & C2 tire rating
Walter------
Driving at high sustained speeds on these old tires was inherently unsafe. Most folks didn't know it, then, though. Of course, the vast majority of cars couldn't achieve high speeds for extended periods anyway. I don't know that the Goodyear Blue Streak tires were "speed rated". However, they were, basically, a racing tire. While Shelby did use them, GM never installed them on any production car that I am aware of.In Appreciation of John HinckleyComment
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Re: C1 & C2 tire rating
Here is a good article about the famous tire test car Shelby did in 1967 for Goodyear. Shelby and Ford were very interested in getting tires from Goodyear that could handle high speeds in hot weather.
Big Tanks In the High Mountains of New MexicoComment
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Re: C1 & C2 tire rating
Bias ply tires of yore were, in a sense, safer than typical modern radials - the common T or below speed rated type that lack a spiral wound nylon cap belt.
Bias ply tires can develop a "standing wave" in the sidewall that can cause failure, but they are not prone to tread separations that can occur on modern low speed rated radials because of the heavy steel belt package, and there have also been significant manfacturing quality issues in the industry. The spiral wound nylon cap belt of H and above spreed rated radials will prevent sudden disintegration in the event of an internal structural failure, which IMO makes them an order of magnitude safer than lesser tires.
Most racing tires are still bias ply, and they have low cord angle construction to stiffen the sidewall which places the standing wave resonance at a very high speed, and they are very light which minimizes radial inertia force at high speed.
Modern aircraft tires are also bias ply. President Reagan's Air Force One (Air Force VC-137 version of the Boeing 707-320B) sits on pedestals that place the main gear tires at about eye level at the Reagan Library in Simi Valley, California, so you can read the information molded into the sidewall. IIRC, they are something like at least 12 plys and have a speed rating something on the order of 250 MPH.
DukeComment
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Re: C1 & C2 tire rating
Makes me wonder what the old USAC and NASCAR cars ran for tires on the paved ovals. I used to watch them back as far as 1955 up at Milwaukee, Wisconsin. They seemed to hold up well, even on the big Chrysler 300's. My favorites were the Packards with their self leveling torsion bar suspensions. It looked like they were duck waddling through the corners. Guess it's like Duke says; the bias ply tires ran well at speed. That's good to know as I thought I was nuts, as I think back, the number of sustained high speed runs I did with my 63 in Nevada on leave (130 mph +) on U.S. Royal 6.70 x 15's (I still have the original new spare in the tub).
Stu FoxComment
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Re: C1 & C2 tire rating
I recall Firestone made special tires for Indy cars back to pre-war days, and maybe sprint cars, but in the early post war years stock cars usually used oversized passenger car or truck tires and word would get around about which ones worked best.
...same with sports car racing tires and some used Michelin X radials beginning in the early fifties. Since most early sports cars were small and of European origin, they usually used European tires until Goodyear and Firestone started making specialized sports car racing tires in the late fifties to early sixties. Dunlop was the first European tire manufacturer to offer specialized sports car racing tires as far back as many the mid-fifties.
DukeComment
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