another tire size question for a c3

hey guys, awhile back i was advised that i have the wrong size tires on the rear of my 79 ( i have 225/60...I was advised that i should be running 255/50..well my
lovcal dealer doesnt stock them but they do stock the 275/50..will these be ok for the rear?? and can i run the 225/60 on the front still?? i cant imagine going to the bigger grips on the front because of turning radius and such.. larry in va beach
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On Sat, 03 Sep 2005 17:14:13 GMT, "Larry & Michele"

====================From Memory >>>>>>>>> and to be truthful Mine is not that good .
The stock Tire size from the factory was 225x70 ...
Today I have 235x60 on the car and to be perfectly honest that tire does NOT fill up the wheel well ...looks stupid in fact... How does your present tire look?
At one time I did run 255's on the rear but can not remember why I removed them...since I had no problem on the rear...
using 50 series tires I THINK (BUT do not know) the wheelwell would look almost empty...
I would ask your tire dealer the actual height of the tires...compare that to what you have on the car now and then pull out the checkbook if you need to...
Sorry to add this BUT my 79 (an L82 ) is an automatic and still would have a hard time burning rubber even on gravel roads...why do you even think you NEED such a wide foot print on the rears...
Actually I run 225x70 on both my 72 and 76 (both 4 sp cars) and still have no need for wider rubber...
Hope this helps you a little...
Bob G 64 & 72 Ragtops 76 79 & 95 Coupes Bob G.
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Bob is right about this.
Here is what you are looking at:
Years Stock Optional Common Replacements
1968 - 1972 F70-15 235/60 - 245/60-15
1973 - 1977 GR70-15 235/60 - 255/60-15
1978 - 1982 225/70-15 255/60-15
The F70-15 was wide compared to the 6.70 and 7.75 tires on the Sting Rays when first introduced on the '68, although needed since they also used a wider (7 inch) rim. In '69, they went wider to the 8 inch rim and the F70 was really a bit narrow, but was the right compromise for ride comfort, ride height, speedometer correction, and so on. By 1973, bumper height laws helped them go to the taller GR70-15 which also filled the wheelwell better. In 1978, tires tired metric with the 225/70-15 and an optional 255/60-15 came to fill the need for a wider tire that was the common desire at the time. In the '70s, it was quite common to see G60-15, H60-15, and even L60-15 on Corvettes. With the low horsepower of the '78 and up cars, the wider 255/60-15 was mainly for looks as they were not needed for acceleration.
Since the chassis and basic body is the same, 255/60-15 tires began to appear on earlier cars quite often. However, the emergency brake cable mount on the trailing arm can rub and cut the tires with some makes and on some years. Basically, the steel 8 inch Rally wheel sits in just slightly more than the Corvette aluminum wheel. Aftermarket wheels tend to sit out much more than Corvette wheels.
On the front, the inner lip was trimmed at St. Louis for those cars receiving the 255/60-15 tires.
So you can get in trouble with larger tires on earlier cars if the wheel combination is wrong. Aftermarket wheels often rub on front when turning as they sit out more, but work at the rear since they don't rub the cable. Being further out does tend to make the rear bearings go out faster.
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Well, that came out looking like garbage.
Years .............Stock ..............Optional ......Common Replacements
1968 - 1972 ..F70-15 .............................235/60 - 245/60-15
1973 - 1977 ..GR70-15 ..........................235/60 - 255/60-15
1978 - 1982 ..225/70-15 ...255/60-15
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Larry, here's my portion of the earlier thread ( tacking on my response to Tom's reply to you):

I checked the thread but couldn't find any recommendation for the 255/50 size. 255/60 was the factory optional tire with 225/70 as standard equipment.
To fill the wheel well as it should be for appearances *and* to bring your speedo back into the usable range, you need to do some math with whatever tire you're looking at. The 50, 60, or 70 number in the tire size is the side wall height as a percentage of tread width. For instance if you reread what I posed above, you get a 157.5mm side wall height by multiplying the tread width (225) by the percentage (70). You're aiming for a 153mm to 158mm side wall height to match the engineered factory specs without going to excessively wide tread or high percentage.
The two tires you spoke with your dealer about won't do you any good with respect to changing the look of how the wheel/tire fills the well:
255/50s would only be 127.5mm tall in side wall (wheel rim to tread) 275/50s would only be 137.5mm in side wall height.
Neither one would do you any better than the tires you have right now (135mm). You ought to be asking your dealer for the factory sizes of the wider 255/60 or the standard 225/70.
Here's waving to ya - \||||
Owen ___
'67BB & '72BB
-- not affiliated with JLA forum in any way -- alt.autos.corvette is original posting -- ___
"To know the world intimately is the beginning of caring." -- Ann Hayman Zwinger
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I have a 77 L-82 and just put on FireHawk 255/60/15 on ..they look nice and handle great!!!

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