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Thread: Gearing?

  1. #1
    RC Racer
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    Gearing?

    Okay, Im pretty new to the whole electric scene, and have been seeing a lot about changing the gearing of the spur and pinion. I have a few questions about this:

    1. What does this change in regards to speed, control, etc.?

    2. How do I do this and is it easy to do?

    3. How does it come stock? (3903)

    4. What is the best (if there is) set up for just bashing around in the backyard type thing?

  2. #2
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    1. Higher gears will give you more top end, with more control during acceleration. Lower gears will have quicker take off, but will be harder to control. 2. If you can tighten A bicycle chain, you should have no problems. 3. Don't know, I don't have an E-Max. 4. I think that Traxxas puts the best gears for general bashing in, from the factory.

  3. #3
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    Quote Originally Posted by Skink910 View Post

    1. What does this change in regards to speed, control, etc.?
    2. How do I do this and is it easy to do?
    3. How does it come stock? (3903)
    4. What is the best (if there is) set up for just bashing around in the backyard type thing?
    1. Smaller pinion = faster acceleration, lower top speed; larger pinion = slower acceleration, faster top speed. The limiting factor to how fast you can go is motor and ESC temperature. Push the truck too fast for too long and things start to smoke.

    2. Changing a pinion is as easy as changing your pants.

    3. I'm not sure what the stock pinion is on the 3903, but if you increase it by 2 teeth you'll notice higher top speed. The key is to make incremental changes in whichever direction you want to go, being mindful of those temps.

    4. The stock setup should allow you to backyard bash without overheating (as long as you're not going wide-open throttle the whole time). What surface(s) will you be running on? Grass, for example, puts more strain on the motors than dry pavement.

    Hope this helps. Welcome to electric!
    Make it idiot-proof and along comes a better idiot

  4. #4
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    2. Changing a pinion is as easy as changing your pants.
    Are there directions on how to do this that come with the truck?

    4. The stock setup should allow you to backyard bash without overheating (as long as you're not going wide-open throttle the whole time). What surface(s) will you be running on? Grass, for example, puts more strain on the motors than dry pavement.
    I will be running on pavement and grass mostly, might have some snow if it sticks around for a little longer.

  5. #5
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    Stock E Maxx 3903 comes with a 17 tooth pinion and 68 tooth spur gear, booth 32 pitch.

    Yes, there are instructions in the manual on how to change the pinion and set the mesh.

    I've found the easiest way to set the mesh between the spur and pinion is as the direction say. Cut you a strip of note book paper, push the pinion next to the spur, hand turn the spur to feed the paper between the two. What you want is a good crisp crimp but not so tight that the gears cut the paper.

    Stock gears with stock motors are the best all around for bashing. You could go higher if you are mostly running it on the road, say 20T pinion for starters. But once you go to plow through the snow you'll want to gear back down to stock 17T or lower.

    I suggest you get a little tube of Loctite and put it on the grub screw when you change up the pinion. Blue is medium strength and red is high strength.

    Hope this helps!

  6. #6
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    Quote Originally Posted by Skink910 View Post
    Are there directions on how to do this that come with the truck?
    No.

    You take off the gear cover, unscrew the pinion set screw, pull the pinion off, put another one on. You set the gear mesh between the pinion and spur using the paper method:

    http://www.youtube.com/watch?v=Dmm5hQBfAyQ

    Quote Originally Posted by M n M View Post
    I suggest you get a little tube of Loctite and put it on the grub screw when you change up the pinion. Blue is medium strength and red is high strength.
    +1 Loctite, it helps keep the grub screw where it belongs!
    Last edited by cooleocool; 03-19-2013 at 08:26 PM. Reason: merge
    Make it idiot-proof and along comes a better idiot

  7. #7
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    Quote Originally Posted by zippogeek View Post
    No.

    You take off the gear cover, unscrew the pinion set screw, pull the pinion off, put another one on. You set the gear mesh between the pinion and spur using the paper method:

    http://www.youtube.com/watch?v=Dmm5hQBfAyQ
    Yeah, I'll have to edit my comment. There is not direction to change out the pinion in the directions. But rather just directions on how to set the mesh with paper.

  8. #8
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    Okay cool, thanks guys!! Just wasnt sure about it all, this has been tons of help!

    So if I understand correctly I probably wont have to do anything if I just want all around bashing? Or do I still need to Loctite the screw and do the paper?

  9. #9
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    If you buy a brand new MAxx, u should be fine. Buy used and i would check it, among other things.

    Unless you are really hard on ur truck and really like wheelies, drive in really high grass, or live in a very hot climate, u should be fine. otherwise, when ur pushing the truck hard, id drop down to like 15/68 to keep motor temps down.

    I also recomend running in training mode for the first one or two runs to allow the brushes to set, but thats just me. also lets you get a feel of the truck. Welcome to the electric side.
    "American Muscle beats import any day of the week"

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