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  1. #1
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    Dewalt 14.4v emaxx gear ratio question *(with pics)

    We purchased the kershaw designs single dewalt kit for an emaxx 3903

    It came with the motor mount which looks great, but my problem with it is that bc of the way it is designed, the smallest pinion that can be used with it(and stock 68 spur) is a 25t.

    This is because the motor sits on top of the transmission, therefore if you run a smaller pinion, you will not be able to mesh it together with the 68t spur.

    I also have the dewalt in my erevo with a 19t and 68t spur and it gets pretty hot. So i can imagine what a 25t will do. Plus, 25t seems inappropriate for hard offroad bashing imo.

    So if i want to maintain decent temperatures and have decent torque, what can i do? Bigger spur? I'm not too good with gear ratios etc.

    Here are some pics.

    with the 25T....


    with the 19t


    Does it look like there is enough room for a 23t pinion? or even a 24t?
    I would hate to buy one and not have it fit..

  2. #2
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    I don't have that tranny but isn't there some grinding down needs to be done to use a smaller pinion, If not run with the 25 and check temps. The temps on mine was higher using the lower pinion size, I run 28T and change the spurs.
    But looking at the pic would the motor fit on the left hand side hole better, or is it camera trickery.
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  3. #3
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    Quote Originally Posted by trax de max View Post
    I don't have that tranny but isn't there some grinding down needs to be done to use a smaller pinion, If not run with the 25 and check temps. The temps on mine was higher using the lower pinion size, I run 28T and change the spurs.
    But looking at the pic would the motor fit on the left hand side hole better, or is it camera trickery.
    Even if I grinded it down to allow a smaller pinion, it would not work bc the motor is on top of the trans, so it would not be able to move over anymore.

    I could put it on the other side of the motor mount, but then it would be off balanced bc the motor would be on the right side instead of the center. And the pinion would still not reach.

    So if I ran an even larger pinion and a smaller spur would the temps be better?

  4. #4
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    The temps should be worse because how gearing works. But i found it much better going from 24T to a 28T. Single motor.
    I'm thinking you have a dual plate, so with two motors you could happily use a higher gearing as the torque comes from two motors not one. Is there a single motor plate i'm not sure. Always check temps when changing gearing and try to keep in range of 140-160. With 140 being the better side.
    Last edited by trax de max; 11-05-2012 at 04:20 PM.
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  5. #5
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    I'll check the temps once we take it for a run. Thanks for the help.

  6. #6
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    I ran a 22T pinion with the stock 68T spur on my 14.4 DeWalt. It ran fine, temps were ok, speed was decent. I worked up to a 28T pinion. Speed was about 30mph but the temps got high enough the thermal protection for the ESC kicked in.

    Now I'm running a modified 70T spur from a Rustler and the 22T pinion. Temps are good, speed is fine (23ish MPH) but plenty of torque.

  7. #7
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    Thanks for the post. It really puts things in perspective.

    We're currently running a 25t and 68 spur and reached 28mph. Temps were fine, but it was freezing outside. We'll see how things go this summer...

    Quote Originally Posted by M n M View Post
    I ran a 22T pinion with the stock 68T spur on my 14.4 DeWalt. It ran fine, temps were ok, speed was decent. I worked up to a 28T pinion. Speed was about 30mph but the temps got high enough the thermal protection for the ESC kicked in.

    Now I'm running a modified 70T spur from a Rustler and the 22T pinion. Temps are good, speed is fine (23ish MPH) but plenty of torque.
    Traxxas ERevo 5603 - 14.4 Dewalt -

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