Radial tire question

[Ed Carpenter]

If you have a 31x13 radial tire how much would it hurt to put the tire on a 15x12 wheel vs a 15x14 wheel? Thanks

[Jim Caughlin]

Are you thinking about trying radials with a stick? Not a good idea, I don't know anyone who is having any luck with manual trans applications. My experience was that they hook sometimes and about every 5th run, it would just blow the tires off. Not a controlled spin either, pretty much a total abort situation.

[GTX JOHN]

I have seen no difference between 12 and 14 inch wheels
on 13/31 Tires

[weedburner]

Radials with a stick requires a different approach regarding the clutch and gearing. The clutches you guys typically run would not be my 1st choice, and something like my ClutchTamer is also needed to control the hit.

Since a radial needs to be dead hooked, there's no need for a deep 1st gear ratio to control tire spin. Less ratio in 1st means less torque available to break the tires loose, but that loss of torque at the tire is offset by spending more time in the gear with the most multiplication. More even gear splits also improve recovery rpm, with the side benefit of less energy discharge on the gearchange. Less energy discharge on the shift lowers the risk of breaking the radials loose.
...You need enough mass in the clutch so that it doesn't overheat while you are leaning on it, also need one that doesn't depend on centrifugal assist to hold.
...With a properly controlled clutch hit, you won't need a 2-step and will be able to launch off the limiter without breaking the radials loose. Higher launch rpm means more energy available to get the car moving when the clocks are running.
...Wheelspeed spikes after WOT clutchless shifts need to be minimized with radials, bring those under control by adjusting clutch base.

Grant

[Mike Rietow]

Originally Posted by Jim Caughlin

Are you thinking about trying radials with a stick? Not a good idea, I don't know anyone who is having any luck with manual trans applications. My experience was that they hook sometimes and about every 5th run, it would just blow the tires off. Not a controlled spin either, pretty much a total abort situation.

Intrinsic value.

[Hacksaw]

Originally Posted by Ed Carpenter

If you have a 31x13 radial tire how much would it hurt to put the tire on a 15x12 wheel vs a 15x14 wheel? Thanks

From everything I've tried with radials, they always liked a wider rim than the tire. When using a narrower rim I had trouble with bad wobble and less contact patch.

[Ed Wright]

I use the 13" X 31", on 14" wheels, so I can run more air (13 to 14 psi).

[Mike Rietow]

,Wide rim. If you can manage deformation early, you're managing spikes. If you can manage W/S spikes, the potential for leaving tracks could present itself, bridging the gap. Wider wheels than normal?

[Ed Wright]

Mike, what is a "W/S spike"? I've never heard that term.

[Mike Rietow]

Originally Posted by Ed Wright

Mike, what is a "W/S spike"? I've never heard that term.

After the car leaves pause, look in the groove Ed. You can get away with it, bias tire. No wheely bar it's essential to not getting on the bumper. Wheel speed spike.