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  1. #1
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    Transmission demystified

    This is in response to the comments about swapping gears inside the tranny to further reduce final drive ratio.







  2. #2
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    i guess im wrong... it looks like it does fit
    .
    .___/ ```i____"""""""ex racer
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  3. #3
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    so did you put it back together and try it out?

  4. #4
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    Quote Originally Posted by ProxyWRX
    so did you put it back together and try it out?
    No. I have a Slash. I don't have a need for reduction.

    It fits perfectly though. Almost like they planned it...

    EDIT: I guess I should say (since the pictures don't show it) that I did put all the gears in and held the shells together while spinning it. It DOES fit. I just did not install it in the truck.
    Last edited by Peowraaku; 06-23-2009 at 10:20 PM.

  5. #5
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    Hmm I wonder how fast it would go like that ?
    At WARN 80% and climbing !

  6. #6
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    Wow, thank you for showing us this. Did you happen to count all the teeth so we can calculate the gear ratio change?

  7. #7
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    from counting the number of teeth from the pic...

    18 and 25 are the number of teeth for the gears that can be switched

    13 is the number of teeth of the other small (looks like metal) gear

    and the diff is 35 teeth

    now i could be wrong i was counting from the pics that he provided
    .
    .___/ ```i____"""""""ex racer
    [_^______ ^ _]Now RCdrifter & Revo
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  8. #8
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    Quote Originally Posted by konaman
    from counting the number of teeth from the pic...
    .
    Duh, why didn't I think of that. Thanks.

  9. #9
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    Small gear has 18 teeth and bigger gear has 25 teeth.

    You guys beat me to it.

    That will probably give it a max speed of about 20 mph with the stock pinion and battery.
    Last edited by Precision Man; 06-23-2009 at 11:08 PM.
    HPI Savage LOSI Mini/MicroT, MRC Traxxas Revo VXL

  10. #10
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    Quote Originally Posted by MuddyTire
    Duh, why didn't I think of that. Thanks.
    no problem... now its up to you to do the math i could but dont really feel like it...

    remember divide gears that are meshing and multiply ratios that are on the same axle.
    .
    .___/ ```i____"""""""ex racer
    [_^______ ^ _]Now RCdrifter & Revo
    .( o )____( o )___Backyard basher

  11. #11
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    Hey guys, guess what, Traxxas did build their tranny for that. If you look on the specs sheet for our little truck it specifies the internal gear ratio of the center tranny. It has two, 5.04:1, (reversed input: 9.72:1). That means that by reversing the internal gears you will get just over half the speed and almost twice the torque. They built it that way so that you could add really big tires. Just check out the manual where it talks about tires. Last paragraph on page 25.
    Last edited by Precision Man; 06-23-2009 at 11:14 PM.
    HPI Savage LOSI Mini/MicroT, MRC Traxxas Revo VXL

  12. #12
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    What is that I can hear, is it a 1/16 summit comming MMMMMM!!!

  13. #13
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    That is awsome Peowraaku thank you for trying this!!

  14. #14
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    I have the original, first shipment of the slash. I still have the original slash tires (converted mine to use 1/8th scale tires)... they fit my revo. Maybe I should make a monster conversion.

  15. #15
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    Quote Originally Posted by konaman
    13 is the number of teeth of the other small (looks like metal) gear
    all shafts are metal. all gears are plastic except for that small one, and it is part of the shaft. the whole thing spins VERY smoothly. i was quite impressed by the build quality. it was that clean when i opened it, and my truck has had the snot beat out of it. i was also impressed by the ceramic looking plate on the slipper. it looks like the brake rotor on a super car. does traxxas spec that material on all their vehicles?
    Last edited by Peowraaku; 06-24-2009 at 01:17 AM.

  16. #16
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    that material is semi-metallic which is in all their "revo" spec slipper clutches if i remember right in the original advertisement for the nitro revo 2.5 they said its the same material that is in brake shoes for 1:1 cars
    .
    .___/ ```i____"""""""ex racer
    [_^______ ^ _]Now RCdrifter & Revo
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  17. #17
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    very cool, thanks for the response. i was away from the hobby when the revo came out.

  18. #18
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    Are those plastic gears in there?

  19. #19
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    Fanatic1074 Are those plastic gears in there?



    Quote Originally Posted by Peowraaku
    all shafts are metal. all gears are plastic except for that small one, and it is part of the shaft. the whole thing spins VERY smoothly. i was quite impressed by the build quality. it was that clean when i opened it, and my truck has had the snot beat out of it. i was also impressed by the ceramic looking plate on the slipper. it looks like the brake rotor on a super car. does traxxas spec that material on all their vehicles?
    Hi everyone, Im a newb!

  20. #20
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    Hehe, sorry i guess thats what i get for skimming through the posts. thanks.

  21. #21
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    So did anyone try switching the gears to see what the speed ended up being?
    MMP-NEU 1112 1.5D 4S MERBE
    BEAST MODE [ON] OFF

  22. #22
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    Quote Originally Posted by Precision Man
    Hey guys, guess what, Traxxas did build their tranny for that. If you look on the specs sheet for our little truck it specifies the internal gear ratio of the center tranny. It has two, 5.04:1, (reversed input: 9.72:1). That means that by reversing the internal gears you will get just over half the speed and almost twice the torque. They built it that way so that you could add really big tires. Just check out the manual where it talks about tires. Last paragraph on page 25.
    maybe this plus 4s lipo would make for cool running and purfect racing speed?

  23. #23
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    yea doing this and putting it on 4s it would prolly do about 30 and have tons of torque
    mini revo on order :)

  24. #24
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    Done thus, 4S A123 LiFePo4, motor was 146f and esc was 125f

  25. #25
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    Put on some Crawler Tires and maki it a Mini-Summit!
    Savage-Modified!, E-Revo VXL, Slash 2wd, Mini-T

  26. #26
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    Sorry for bringing back this old thread, but I had a question regarding the transmission 'underdrive' I just called traxxas and customer support says that the underdrive in the manual is referring to the spur pinion combo to compensate for the larger tires, but Im not buying it. So what I see here in the orignal post is what the underdrive gearing is?

    Also if the above is the underdrive gearing and I run 4" tires, do I just stick with the pinion I was previously running the the stock tires. Thanks for the help.
    ERBE... Best RC Ever!

  27. #27
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    Quote Originally Posted by cch1978
    So did anyone try switching the gears to see what the speed ended up being?
    did anyone, I guess I will have to try it!!!
    MMP-NEU 1112 1.5D 4S MERBE
    BEAST MODE [ON] OFF

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