Suggested axle gear ratio

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racedog98

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Jan 5, 2013
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2.5 build. What gear ratio thoughts. Truck is 97 dodge 2500. Full built auto. Wanting to run 33 inch tires.
 
4:88 and then as you build to make more power you can step up to 35's.
 
Doesn't seem to be many opinions on the subject. Or others are waiting to see posts before offering up their thoughts.
 
I run a 2.5 truck and probably make in the ball park of 850-900hp but our 2.5 turbo rules out here limit us on power compared to bob rules. My setup is a ppump 24 valve with a auto and I'm running 4.88 with 35's. I typically carry 3400-3600 just depending on the track.
 
Thanks for the info Cummins41. Have you ran 33's with your set up ? Roughly what stall speed are you using on converter. And are you going to 3rd gear during the pull ?
 
I ran 33in interco truxes last season and I actually got out of the power band a few times it seemed so that's why I went to 35's to pull the rpms back down. And for a stall, I'm running a 2900 stall. I run a manual valve body with a ratchet shifter and I control lockup. I start in 1st, shift twice and then lock it up. I'll post a video of it so you can get a better idea.
 
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Getting back to you Cummins41. Videos were great. Thanks for sharing and for the insight. Thinking at this point that 4.88s is the way to go. I just thought there may have been more opinions expressed. Thanks again.
 
I was going to comment earlier, but I'm running a manual transmission. I do run 4.88 gears with 33" tires.
 
I forgot to mention, i tried 4.30's on 33's before this setup and it flat out didn't work. Made the truck drop 2k rpms when I locked up
 
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I run BOB rules, we run 488's with 35's. Pulling DD (4th) on the low side. As Cummins41 said, put in a set of 488's and build for power to turn 35s with them.


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The top truck here in COTPC are running 4.56 or 4.56/4.63 combo for you Dana 80 guys. Gears depend on power and the type of tracks you pull on.
 
I'm running 4.56/4.63 combo with 35 truxus in front and dual 35 toyo m/t's in rear. Running an Allison with 3000 stall converter. Come out in 3rd, lock then tap shift to 4th. Never falls off charger and stays in forth the whole way down. Running a ED 2.6 Carrying between 4300-4500 rpm
 
Thanks for the information on axle ratio. What type of lockers (front and rear) are most guys using ?
 
What are you 4.88 guyss wheel speeds??!! I'm running 4.56 with 35s and hold around 3500 rpm down sticky, clay tracks. That's with an 04 common rail dodge...our rukes are identical to BOB EXCEPT, we have to run cast wheels, no billet. With 4.88s, aren't you guys blowing past torque band and not even bringing it down to it?
 
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