31x10.5W or 33x15.5W ?

[rompn63]

5 speed 3600lbs. I'm chasing poor 60" times, my tires spin at the hit.
I have 31" 10.5 W with a 5.14 rear gearset and a 2.87 1st gear. Will a change to the 33" 10.5W help or would changing to a 4.86 rear gearset help calm down my hit. How about 33" tires and a 4.86?
I'm not worried about my trap rpm's

[Jason Moulton]

The 33.0/10.5-15W (part # 3069W) will be more aggressive than the 31" tire (read - more bite). This is due to the increased contact patch with the larger rollout. As you indicated, it will also take some gear away.

The 31.0/10.5-15W (part # 3068W) is cabably of some amazing performances. Can you provide some more information about your combination? (ET, trap speed, rpm range, suspension, air pressure your using, rim width etc?)

Maybe we can help you with what you have.

Thanks,

Jason Moulton

[rompn63]

Best et was 9.64 @ 140mph 1.41 60' with a 4.57 gear set/6800rpm. 31" M/T 10.5W tires running 9.5-10psi on 10" rims.
Four link with Strange double adjustable rear shocks. I run a Boninfante 10" single disc clutch.The old engine (Pontiac 455)made788hp at 6400 and 707 lb ft torque at 5200. Putting in a new combo with 900hp @ 7200(guess)and 750 tq. (will dyno this april)
I have a 5.14 and a 4.86 available and need new tires so I though with the increased torque and horsepower the 33" Mickeys would help my 60' times. The 33x10.5 are as big as I can fit in my wheel wells.
Thanks

[Jason Moulton]

Well, for that ET your 60 ft times are certainly off, but the 31" tire should be enough. With you can being on the heavy side, have you tried higher air pressure? Can you fit a wider wheel? Other than that, you certainly have the adjustability with the chassis and clutch to make it work.

Again, the 33" tire will help, but it may mask some other areas for improvements.

BTW - Those are some stout dyno numbers!

Thanks,

Jason Moulton

[rompn63]

Jason, I will most likely stay with the 31" tires and see if I can fit a wider (12") wheel. How wide of rim would you reccommend if clearance was not an issue? Is there a lot to gain with the wider rim?
What would be the highest tire pressure you would reccomend trying?
Thanks

[Jason Moulton]

I would not go any wider than a 14" rim. Make sure if you go wider than 10", I'd put 16 rim screws per side to help better secure the tire. With bias tires, the wider rim (to a certan point) can help stability, and improve traction. Of course this goes hand in hand with the design of the tire.

Thanks,

Jason Moulton