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  1. #1
    RC Racer
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    can someone explain gearing please

    ok.... i don't know if i just didn't search long enough or what but i always read on here about ppl changing their gearing or fixing it. i really need someone to explain to me or maybe direct me to a thread that explains gearing. somebody had 20/40???? I'm lost on that subject. any help is appreciated. Thanks in advance
    The nitro..it's..it's..makin..me..sooo..wooozy

  2. #2
    RC Turnbuckle Jr.
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    20/40 gearing is more for top speed, but you still have good acceleration. Here is the 20t with the right pitch to run with the 40, 38, and 36 spurs. I love the 20/40 and 20/36 gearing, never tryed 20/38.
    No more money for rc trucks I got 1:1 truck

  3. #3
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    There are two gears. The spur gear and the clutchbell. The spur gear is the larger black gear near the back right wheel. The clutch bell is the smaller gear on the engine.

    When the spur gear has more teeth your car has faster acceleration but goes a little slower on top end

    When the spur gear has less teeth the car has less acceleration but will go faster on top end

    When the clutchbell has more teeth there is more top end but less acceleration

    When the clutchbell has less teeth it has more acceleration but less top end.

    Lets say you have at 40 tooth spur gear and a 12 tooth clutch bell.

    You put the 12t S/G on it with the 40 tooth CB.{clutchbell}
    You then decide to put a 16 tooth CB on it. You will get more top speed but less acceleration. If you put a smaller gear on it you will get more acceleration.

    If you put a 36t spur gear on it you will get more top speed but less acceleration.


    So combinations gives you different results such as alot more acceleration or alot more top end.

    CB=clutch bell
    S/G or sg= Spur gear
    t such as 40t= teeth

    When you get different combinations you get different results

    Tell me if you dont get it
    Last edited by rustler 007; 01-26-2009 at 08:27 PM.
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  4. #4
    RC Turnbuckle Jr. RC-Crazy's Avatar
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    20/40 is Revo gearing, ratio is 2:1(most is for on-road); stock Jato use 24/54, ratio is 2.25:1(on & off road), most ppl use 20/54 on off road w/ bigger tire, ratio is 2.70:1.
    smaller ratio means more top end speed, less tq.
    bigger ratio means more low end power but less top speed.
    Slash PE & Ja-two.

  5. #5
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    oh, i used random gear teeth.
    You can only have 2
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  6. #6
    RC Racer
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    ok thanks. i think i got it. that's just what i needed. examples. of course mine is stock. but i'ma read this example for a little while so i can fully understand it and play around with the gearing on mine. i have another thread on here that i'll keep posting what i'm doing to it. Thanks a lot. now i won't feel so lost when readin other posts
    The nitro..it's..it's..makin..me..sooo..wooozy

  7. #7
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    my favorite topic.....
    gearing is a great thing... when chossing gears, the pitch is as important as the count... therefor u can have a smaller cb (tooth count)" bhut have a bigger clutchbell...
    remeber... adding one tooth to the cb is equal to stepping down 3 on the spur....

    and just for giggles.... some of u who want to stay with the .8 module... older
    kyosho and tamiya cb 's will work on the 3.3 and u can get them in 26 and 28
    been there bought that

  8. #8
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    ooooo nice to see u pop in Forbes.
    O.S.|HiTech|RPM|THS|50wt

  9. #9
    RC Racer
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    you lost me a little forbes. so you're sayin that if i get a bigger sg, it makes the cb seem/act smaller?
    The nitro..it's..it's..makin..me..sooo..wooozy

  10. #10
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    ok this gets kinda complicated to type so i will try...

    if u step up one tooth on the cb... it is equal to steeping down 3 teeth on the spur. so with that.. it always best to get a cb to get u close to what u want... and use the spur gear for fine tuning... (peak powerband)
    now when it comes to pitch (module) that is the distance in the tooth spacing.
    for example:
    jato is .8 module
    revo is 1 module.
    look at a revo 20 cb, it is larger than a jato 24 cb. this is because the pitch/ module is wider.
    so to say a larger tooth cb is better for top end is not always true... depends oon the module/ pitch.
    so u can have a larger cb with a smaller tooth count.... same will apply with a spur gear...
    been there bought that

  11. #11
    RC Turnbuckle Jr. RC-Crazy's Avatar
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    Yep, that's why the Revo CB doesn't work w/ Jato SG....
    Slash PE & Ja-two.

  12. #12
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    Pitch is just the deepness of the gap beetween the teeth. The revo has a deeper gap than the jato
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  13. #13
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    actually... it is measured from the top of the tooth...
    been there bought that

  14. #14
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    I think the easiest way to think of it is... consider a multi-speed bicycle, like a 10-speed. Imagine the engine/clutchbell is the front gear.

    When you have the chain on the smaller front gear and the larger rear gear, you can accelerate/climb better, but you can't go very fast, even on flat pavement.

    When you have the chain on the larger front gear and on the smaller rear gear, you won't accelerate/climb very quickly, but you can reach a faster top speed once you get going.

  15. #15
    RC Racer
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    thanks ya'll i'm startin to understand, i think. i saw one of desert's threads and he said he uses 20/40 revo gearing. Example: I would have to use the whole revo setup for it to work? or can the gears be interchangeable? or are the gears almost like "general" gears and the setup is the only thing that is different

    i'm understanding the beginning of the thread. i guess this is my other question about it
    The nitro..it's..it's..makin..me..sooo..wooozy

  16. #16
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    You have to use the revo clutch bell and spur. Gears are 95 percent of the time different pitch when you come across different classes or manfactures of rc. For instance the monster trucks usualy have different pitch than stadium trucks. HPI uses different pitches than traxxas. Nitro trucks usualy wont have the same pitch as electric ones.
    You can only have 2
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  17. #17
    RC Racer
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    Quote Originally Posted by rustler 007
    You have to use the revo clutch bell and spur. Gears are 95 percent of the time different pitch when you come across different classes or manfactures of rc. For instance the monster trucks usualy have different pitch than stadium trucks. HPI uses different pitches than traxxas. Nitro trucks usualy wont have the same pitch as electric ones.
    gotcha. Thanks
    The nitro..it's..it's..makin..me..sooo..wooozy

  18. #18
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    on the issue of gearing has any one used the 22 tooth clutch bell from axial and like a 36 or 38 tooth spur from a revo I have been thinking about doing this to use some of the power from my axial .28 let me know what you think.....

  19. #19
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    As long as we are on gearing I am looking for offroad tires and I am concerned how it will effect performance and shift point if I get a different size tire. I am thinking about the Pro-Line Dirt Hawg 30. They are bigger then the 2.8 Traxxas uses...correct? Can I just put them on or will they require adjustments?

    Sorry for all the newbie questions.

  20. #20
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    Quote Originally Posted by rustler 007
    You have to use the revo clutch bell and spur. Gears are 95 percent of the time different pitch when you come across different classes or manfactures of rc. For instance the monster trucks usualy have different pitch than stadium trucks. HPI uses different pitches than traxxas. Nitro trucks usualy wont have the same pitch as electric ones.

    false.... there are only 5 diff pitches i know of when it comes to nitro....
    electric is 4 diff....
    true elec and nitro will diff in pitch.... i have several kyosho, hpi. tamiya cb that will match.... depending on ur spur... find a cool LHS that will let u mesh gears and spend a day browsing... u will be suprised how much stuff actually meshes and works...
    been there bought that

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