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  1. #1
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    Convert 32p to 48p

    Done some reading and have not found anyone that's done it to a summit, but anyone converted the pinion and spur gear to 48p? I can get a much higher spur gear tooth count on a 48p. I'm trying to get the lowest gear ratio I can. Best I've found is 7t pinion and the stock 68t spur. Need moar lower ratio!! Lol

    Thoughts and suggestions?

    Thanks

  2. #2
    RC Turnbuckle Jr. Cameron's Avatar
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    Does Traxxas even make a spur that can fit the Summit/ERBE platform in 48p ?
    I dont think they do.

    Then again i run Mod1.0 on everything other than my summit on stock gearing.
    (RAH) (AH) + [ROMA (1+MA)] + (GA) + (OOH)(LA)

  3. #3
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    I have bought all sorts of different size spurs from Kimbrough in both 32 and 48 pitch for my rock crawlers and trail trucks. The spurs I bought have dozens of mounting holes to fit a plethora of different manufactures

    Search up " Kimbrough 96 Tooth 48P Precision Spur Gear #142 "

    Its the biggest I can find... it would still be smaller than the 68 32p gear.. 68t 32p works out to a 102t 48p gear.
    Last edited by madkawi650; 12-24-2012 at 05:59 AM.
    Always in Trouble for trying to help out.

  4. #4
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    Thanks for confirming my thoughts, kawi.... I kinda thought that tooth count would change for the same gear if pitch was changed.
    Whatever it is I just typed... could be wrong.

  5. #5
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    Perfect explanation, thanks

  6. #6
    RC Turnbuckle Jr. noir 522's Avatar
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    But keep in mind just cuz a gear in 48p has more teeth doesnt neccesarilly change the ratio. It more based on the diameter of the gear itself. The smaller teeth are possibly weaker and if the ultimate diameter is the same then there is no gain.
    Kinda sorta.

    What I did to get a lower gear ( first stick with the stronger 32p gears)
    1. either cut you motor shaft in half or use a 1/2 inch spacer to secure the motor further away from the spur gear. This will give you the space to use a 8t or 7t 32p 5mm pinion. You may can find a 6t but that would be cutting it close.

    2. Take a dremel and cut the area on the chassis around the spur gear. Then buy a 72t 32p old style E-MAXX spur gear. Trust me it will fit.

    When done the gearing will whine like a lawn mower out of oil but the torque will be great and the crawling is nice and slow. I forgot what the calculation was but that my man is some LOW gearing
    MAN, Use Common Sense.
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  7. #7
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    thanks for the info!

    but,gearing is gearing though isnt it, 68t spur and 10t pinion is a 6.8:1 ratio ( driven/drive= ratio) no matter of diameter. just as if you did the same tooth counts on a 48p. correct me if im wrong, but im basing this off my mechanic schooling and 4x4 building background on real size trucks. only starting to learn about scale stuff. so any info is appreciated!

    thanks

  8. #8
    RC Turnbuckle Jr. noir 522's Avatar
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    I, by no means am a high tech wizard. In college i failed calc III three times and promptly changed my major from engineering/ comp sci to nursing.

    But gear teeth are simply there to create friction/ traction for two turning wheels. And size and pitch are simply designed for strength, physical placement, and universal compatibility. Cuz when its all said and done gears are simply two circles with only there diameter making a difference

    For example lets take two equal circles 1:1




    The same size circles give a 1:1 ratio.
    Now cut either large 32p teeth into them or cut smaller 48p teeth into them. The ratio is still 1:1 all the teeth are doing is guaranteeing that the gears do not slip when turning.

    Now make one circle smaller and again cut 32p or 48p teeth into them ( assuming that the tooth size does not alter the diameter) does the ratio not equal the same?



    But you will find that smaller 48p teeth will fit better on a 1/8 inch scale motor stem while the the summits 5mm motor stem can take advantage of the larger and stronger 32p teeth

    But I still retain the wright to be rong
    MAN, Use Common Sense.
    Outside? THERE IS NO BOX !

  9. #9
    RC Turnbuckle Jr. noir 522's Avatar
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    HSomeone correct me if I am wrong, but the reasons that the different teeth size/ numbers is that on a ( for example) a 8mm diameter gear one could fit 26 teeth of size 32p, while on the same 8mm gear one could place 35 teeth of size 48p.

    Now match the first gear with a larger gear, say 10mm in diameter. On this second gear you could place 29 teeth of 32p and 41 teeth of 48 p size.

    But since both the diameters are still the same the tooth numbers ( though different ) will calculate out to the same ratio. ( ps dont use these numbers , I just threw them out there as an example. And yes I am bored and its a slow night at work right now)
    MAN, Use Common Sense.
    Outside? THERE IS NO BOX !

  10. #10
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    Quote Originally Posted by noir 522 View Post
    HSomeone correct me if I am wrong, but the reasons that the different teeth size/ numbers is that on a ( for example) a 8mm diameter gear one could fit 26 teeth of size 32p, while on the same 8mm gear one could place 35 teeth of size 48p.

    Now match the first gear with a larger gear, say 10mm in diameter. On this second gear you could place 29 teeth of 32p and 41 teeth of 48 p size.

    But since both the diameters are still the same the tooth numbers ( though different ) will calculate out to the same ratio. ( ps dont use these numbers , I just threw them out there as an example. And yes I am bored and its a slow night at work right now)
    You are absolutely right on. It is the diameter of the wheel that will affect the ratio, not the number of teeth. 32p gears having larger teeth are also stronger and harder to strip. For a heavy RC where torque is abundant, 32p would definitely be the smart choice.

  11. #11
    RC Turnbuckle Jr. pavmentsurfer's Avatar
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    The "pitch" of a gear simply refers to the number of teeth per (not sure if its inch or what). You cant fit as many larger teeth (32P) per inch as you can fit the smaller 48p teeth. So the exact same size gear will have more teeth with a 48p setup than a 32p setup.

    Before you get caught up in how many teeth you do or dont have you need to do the math and find out your gear RATIO.

    Divide the number of teeth on spur, by the number of teeth on the pinion.

    68/14= 4.85

    Your stock ratio is 4.85

    If you want LOWER gearing, you need that number to be HIGHER. Tooth count is irrelevant. The revo/summit platform is limited in how large a spur you can fit. I believe a 68t 32p spur is as big as you can go.

    But I know you can get down to an 8 or 9 tooth pinion, which would give you a ratio of 8.5

    For comparison. A 4.85 (stock) radio in 48 pitch would be ABOUT 18 or 19/68 gearing. I know you can get down to a 12 tooth 48p inion so the lowest I can see you getting in 48p would be about 5.66 (give or take a bit).

    32p really does provide the best compromise in this situation.

    The other issue you may have is with motor mounting. Because your limited in how big your spur can be, you can only really adjust your pinion. BUT, there is only so much adjustment in the stock motor mount. You may not be able to get a pinion with less than 10 teeth to mesh.

    On top of all that, I dont believe traxxas makes a 48p spur that fits the summit style slipper. Maybe they do or someone else does. Ive never seen it done. The titan 775 produces so much torque youd probably just strip the spur every run.
    Last edited by pavmentsurfer; 12-26-2012 at 01:36 PM.

  12. #12
    RC Turnbuckle Jr. noir 522's Avatar
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    A touch of dremel on the silver motor mount plus the larger 72t spur gear will allow for an 8t pinion
    Give a man a Dremel and he could end hunger and make world peace by noon.
    MAN, Use Common Sense.
    Outside? THERE IS NO BOX !

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