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Gear Ratio For Sled pulling?

15K views 10 replies 6 participants last post by  BDS 
#1 ·
I am looking to possibly re-gear my truck for a better final drive ratio in 4 low for sled pulling. I have done some research but have not found what I'm looking for. I gather a 13.0-14.0 final drive is a target for sled pulling but I have a 4R100 and all I have been able to find is ZF or NV values for a final drive ratio. I'm running a 4R100 with 35's with 3:73's with a 271 T-case, with running approx 3400rpms= not enough of a final ratio for third gear in 4x4 low. I'm in the 10.0 ratio range with the convertor locked??? not sure if I did the formula right.

What gear ratio/tire size set-up is optimum for what I'm looking for?
This is for the work stock class (2.5) and I'm at the low 500hp range.
 
#3 ·
Maybe you should move this to the sled pulling section or link to it in that forum.
 
#4 ·
4.56 will get your rpms up but I preffer a 33" inch tire...if your still driving the truck on the street which I asume so with a 2.5 truck and wana keep the 35s id go with a set of 4.10s and a true-trac l/s front and rear, then your rpms will be up some on the track and not to high on the freeway
 
#5 ·
I appreciate the info...I wouldn't mind going all the way up to 4:56
and dropping tire size for pulls if it will all come together in the
end. As far as the true trac I was planning runnning one in the rear
and an ARB in the front.
Motor is good, trans is good, now its time for the axles.

What is the final drive ratio with 33,s and 4:56 gears...I'm conning up with 11.65???
 
#6 ·
should be about 12.4. thats what i came up w/ anyway cause thats what i run.
 
#7 ·
Just to give you some ideas.

When the American Ride was limited to a max of 4000 rpms. The truck ran a final drive ratio of 13.571 with 35" tall tires.

Now that it runs more rpms it runs a final drive ratio of 16.153 with 35". These were set with a 32 mph tire speed goal.

I would guess that based on your hp of around 500 or so I would shoot for a wheel speed goal of 24 mph.

In second (1.54) low range and 35" tire with 4.10 gears this would put you at 24 mph = 4002 rpms.

In second low range 33" tire and 3.73 gears this would be 24 mph = 3840 rpms.

Now if you can't get those rpm's then you will have to go to 3rd gear or 1 to 1 ratio in the transmission.

with 33" tire's at 24 mph
3.73 = 2493
4.10 = 2741
4.56 = 3048
4.88 = 3262
5.13 = 3429

With 35" tire at 24 mph. 1 to 1 in the tranny
3.73 = 2346
4.10 = 2599
4.56 = 2891
4.88 = 3093
5.13 = 3252

So based on your 3400 rpm max goal I would say either 5.13 with 33" tires maybe a 35" tire.
 
#8 ·
well Im assuming 3400 since thats pretty much where the power stops on the dyno. I was hoping since it is such a low rpm I could try and gain some back by re-gearing and tire swapping. I'm getting tired of slow pulls and not enough rpms at the big end of the track with 35's and 3:73's. I guess i'll run 35's on the street and 33's for sled pulling with 4:56 gears...

Sounds as good as I can get for a street driven sled puller?

Any other suggestions?
 
#11 ·
Thanks alot!
 
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