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  1. #1
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    Question Right gear setup om New Brushless

    Hej.
    Just unbrushed my ST Rally with a 4000Kv setup.
    Now im thinking GEARS ?
    The standard 12T on 83T Spur, the would be "eaten" somewhat fastere, right ?
    Thinking about 16T or 19T Pinion and Maybe Going 76T on Spur, or staying on the 83T Spur...
    Going for a littel bit more acceleration. And somewhat more topspeed.
    Should i stay om the 48pitch or go down(up) to 32pitch...

  2. #2
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    Hi, fellow Scandinavian!
    Are the rest of the ST Rally stock? If so, definately get the slipper clutch from the Slash 4x4 (#6878) and the aluminium slipper clutch adapter (#6893X). Also the plastic center drive shaft has to be replaced by the aluminium shaft (#6855) together with the front steel drive hub (#6888X).
    This also means that you'll have to get a 32p motor pinion (the slipper assembly comes with a 54T 32p spur gear).
    With a 4000kV motor a 12T pinion is a good starting point, depending on where and how you drive it.
    Last edited by Viking; 04-05-2018 at 10:35 AM.

  3. #3
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    ^ Perfect list of upgrades

    I have an older rally (currently race it in 4x4 SCT) and I've had no problems with any of the gears (I did have to replace the spur gear after bending the blue driveshaft). All you have to worry about is gear mesh. Oh it has that slipper clutch. Yeah, you're going to want an actual slipper clutch and not the 'high stall' clutch.
    Last edited by Sprinkletron; 04-05-2018 at 11:55 AM. Reason: Slipper
    Guess who's back.
    Back again.

  4. #4
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    Talking

    Hei Viking. Tak skal du have !
    As of now it is total standard setup, the engine and esc is in the mail (Hobbywing quicrun 5660"4000kv"+10BL60 esc).
    That trx6893x is that a bearing ? I was thinking of getting the trx5352r HD Rebuild kit. Slipper clutch.
    The swaybar kit trx6898 is also in the mail �� along with 76t spur and 18t pinion both at 48 pitch.

  5. #5
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    Remember to watch that center plastic shaft.
    Guess who's back.
    Back again.

  6. #6
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    Bare hyggelig kunne hjelpe, Warley!

    The alu slipper clutch adapter 6893X is not a bearing but a bushing on the slipper clutch assembly (which seats into the motor mount bearing). The stock plastic part (6893) on the Slash 4x4 slipper clutch often melts and has to be replaced with the alu part.

    The reason for recommending the slipper clutch from the Slash 4x4 is that the "high stall clutch" in the ST Rally won't hold up to brushless power.
    The Tra5352R rebuild kit must be combined with Tra5351 to build the Revo spec slipper clutch. This is a good upgrade, even better than the stock Slash 4x4 parts. You will need a new 32p spur gear also (Tra3956 is the stock 54T spur gear on the Slash 4x4).

  7. #7
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    With these geears, Where am i in speed kmt/mph.
    The Stock Rally aint that fast but the slash is Much faster. Seen it at 90 Kmt Stock! Is this Where im ending ��
    Motor Pinion 16t plus 50t Spur. @ 4000kv .
    Setting it jo like Viking told me ��

  8. #8
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    Sprinkletron.
    Im changing it. Or its plastic all over the place ��.
    Looking forward to throttle it..
    Thanks ��

  9. #9
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    Quote Originally Posted by Warley View Post
    With these geears, Where am i in speed kmt/mph.
    The Stock Rally aint that fast but the slash is Much faster. Seen it at 90 Kmt Stock! Is this Where im ending ��
    Motor Pinion 16t plus 50t Spur. @ 4000kv .
    Setting it jo like Viking told me ��
    The stock Slash 4x4 is nowhere near reaching 90 km/h without overheating (a few speed run passed may be possible on 3S and 13/54T gearing -> 80km/h). For consistent high speed running without overheating you'll need an 1/8 scale power system.

    I assume you are going to run a 2S LiPo battery with the 4000kV motor (on 3S you better watch the temps closely, or change to a lower kV motor and gear it higher).

    Expected top speed with 16/50T gearing and 4000kV motor:
    2S: 70 km/h (43mph)
    3S: 105 km/h (65mph) (But you will likely overheat and burn the motor and possibly also smoke your 60A ESC - GEAR DOWN!)
    Last edited by Viking; 04-06-2018 at 08:39 AM.

  10. #10
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    @Viking,

    Thanks for listing those parts in the original reply a few months ago. I had picked up the driveshaft and slipper but there was no information about needing the adapter anywhere. I discovered it wouldn't fit when I had it all apart and figured I was missing something. Just wanted to say thanks for that info, I wish it was listed under the parts list on the Traxxas parts page.

  11. #11
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    Hey guys I to run the rally in act racing but I run outside dirt oval. The only thing I have done was put the velinium system in it of course the slipper upgrade. The rest is still stock. This thing is a beast n tough as nails.flipped to no end hit the wall harder than I want to but keeps going strong. Im sorry I also put the slash a arms just to widen it up with the adjustable links. Now I'm going to throw mod 1 gears into it and see what happens. Best of luck to myself and others who race/bash..
    Sometimes you have to turn right to go left !!

  12. #12
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    Quote Originally Posted by Viking View Post
    I assume you are going to run a 2S LiPo battery with the 4000kV motor (on 3S you better watch the temps closely, or change to a lower kV motor and gear it higher).

    3S: 105 km/h (65mph) (But you will likely overheat and burn the motor and possibly also smoke your 60A ESC - GEAR DOWN!)
    +1 on this. Been there and done that with a Slash on a Reedy 4000kv

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