Justin79-L-82

I was looking at the tire diameters for bfg ta's and found equally matched tires for 275/50s and 275/60s. Here are the measurements for the tires with close to matching front tires

275/60r15 - 28 with 235/70r15 - 28
275/50r15 - 25.9 with 225/60r15 - 25.6
255/60r15s measure at 27.1

Would it be a bad idea to get larger diameter tires like the 275/60's? WOuld that kill off the line performance? Or would it be a better idea to get the smaller diameter tires? Or should i just stick with 255/60's all around? WOuld there really be a big traction difference between the 275's and the 255s?

Jvette73

Tire diameter does play into the overall final ratio equasion. A taller tire will theoretically yeild higher top speed if yur engine has enough power to get there. A taller tire will ruduce rpm's at criuse speed. A shorter tire will give you better tq off the line. A shorter tire may weigh less and have that weight situated closer to the hub which would rob less power from the drivetrain. It depends on the look you want as well as weather you want to increase off line tq or decrease cruise rpm? Different diameter tire will also effect the speedo reading. A taller tire will make the speedo reading slower then you are actually going. Obviously vice versa for a shorter tire. There is trade offs both ways. Rubber compound is more a factor in traction than width. There are some gear calculators on the web that will let you add different tire diameters and see the different results. I would send a link but lost it when we got a new putor. Im runnin 235/60-15 which are 26.1" diam.

Jvette73

heres the link>>>http://www.prestage.com/carmath/calc_Gears.asp

yur ratio for an auto trans in 3rd gear would be 1.00

The Money Pit

I spent a fortune learning the hard way,so concider this. If you're planning on sticking with the stock rims,the best overall combination would be P255-60's all the way around. The diameter is not that far off stock,the fit to the rim and wheel well isn't bad,and the cost for replacement is very reasonable.

Now if you're going aftermarket,and have no budget constraints the sky is the limit. I stayed with the 15 inch rims for two reasons. First the tire replacement cost. I drive mine 20,000 miles a year.Plan on tires every two years to keep the tread fresh. The roads here suck and a drywall screw in the tread every six months is not out of the realm of possibilities.Secondly I prefer the look of a 15 inch tire on this body style Vette.

The other thing to concider is the performance gain or loss by changing tire sizes.A taller tire may look right on the car,but by increasing the rear tire diameter,you not only reduce the effective gear ratio,the increased sidewall height will detract from the overall handling in the turns.I ran P275 60's on the rear once and the rear danced like a hula girl when I cornered hard.This is why I changed to the P295 50's which were shorter,yet offered more tread.
Hope some of this helps.
:steering:

bence13_33

If you take the 275-60-15 and compare how it hooks up to the 275-50-15 I would imagine the 275-60-15 will hook up better coming off the starting line. There are trade-offs when dealing with sidewall height. A taller side wall will aid in off the line traction. However a taller side wall isn't all that great when comes to handling.

FYI my buddy is currently experiencing this problem with his 514 Mustang. He is running 315/40/17s (I believe) on Cobra-R rims. The tires have a really soft tread compound but the small side wall makes it a bear to try to hook up with.