Gentlemen, can anyone tell me what is the widest tire and rim size they have had experience with that would fit the front of my 74. What I would like to do is put on the widest combination available, (without interference problems) and then measure the exposed fender line and choose a similiar rear tire and wheel combination. Any pictures of aftermarket tire wheel combinations would be appreciated. I also would like to know the offset you may have tried. Any help would be appreciated, Carl.
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Re: Oversize wheels and tires
When I bought my '72 coupe, it had 245/60's with late 70's 15"x8" aluminum Corvette wheels on it. They were about as big as I would want to go because the fronts rubbed on the inner fender wells when turned full lock. I have since replaced them with 225/70's on 15"x8" steel rallys (to closely approximate the orig. F-70 tires) and are just about right, maybe a little tall (the speedo reads about 8 mph slow probably due to the slightly taller than factory F-70 bias plys). The cross reference chart says that 215/70's will most closely match the orig. F-70's. One book I read said that you can go as big as 255/60 on 15"x81/2" but that seems too wide to me. Also, be sure to get wheels that are made to fit a Corvette if you're not going original. Many aftermarket wheels will rub on the brake calipers which obviously isn't good.
Hope this helps,
Bob Booth -
Re: Oversize wheels and tires
255/60s on the regular production wheels were offered as an option in the mid to late seventies, but probably not as early as '74. They will probably work, but modern 255/60s are designed for looks, not performance, and usually only carry only an "S" speed rating. The best tire to run for performance is the 225/70VR-15 Michelin XWX. They were OEM on Ferrari Daytonas and some Pantera (rear) in the early seveties. Coker tire is the exclusive distributor in the US, and they are expensive -- about a thousand bucks a set. Compound is soft for excellent grip, but will only yield about 20K miles of "normal" driving. Speed rating is the old "V" or "over 150 MPH with the top speed determined by the vehicle manufacturer".
DukeComment
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Re: Oversize wheels and tires
Carl,
I am not sure how applicable the "chrome bumper" stuff is, but as was said above I know of a friend running 245/60 Gaterbacks on stock rims on a 1972 and they rub slightly on the front (back of tire hits the frame at full lock). He seems not to find it a problem. I run 225/60 on a stock rim on my 1970 and have no contact with frame or fiberglass.
In both cases rear tires clear just fine.
If you are considering this you should be aware that the modern 60 series tires are substantially shorter than the F70's that are stock on these cars. I have not done the math, but I believe it turned my 3:70 into at least 4:11 He He He. More fun than I can stand around town. On the road???? Oh well there is a price for every bit of FUN.
Terry
TerryComment
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Re: Depends on width of tire.....
Some 60's series tires are shorter than 70's series depending on the width of the tire. The width designation is a constant, but the profile is relative to the width. For instance, a 255/60 designation on a tire means that it is 255 millimeters wide and the sidewall height is 60% of the width, or 153 mm. So the tire is about 10-1/4" wide with the sidewall being about 6" tall. Total mounted tire height on a 15" wheel is about 27". Conversely, a 195/70 tire is about 7-3/4" wide with a 5-1/2" sidewall. On a 15" wheel, this tire is 26" tall, 1" shorter than the 255/60. So you can see that if you do the math, you can end up with exactly the size tire you need. Of course there are some variables, like, if you use a wider wheel than normal the tire will be spread apart more at the bead and will make the tire slightly shorter, as a narrower wheel will do the opposite. These numbers are based on the reccommended wheel width for the tire being used.
Regards,
Bob BoothComment
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