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  1. #1
    RC Competitor
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    Spur gear question

    I replaced my sons 20 tooth pinion gear with a 19 tooth.
    He lost a little quickness, but gained top speed.

    What is the difference if I go from a 90 tooth SPUR gear to an 87 tooth?
    Will that effect speed or quickness or neither?

    Thanks

  2. #2
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    Absolutely. Look in the manual. It has a chart with all of the combinations. It also has a formula for calculating your own.

    Lower final gear ratio is higher speed, less torque. Higher gear ratio equals more torque, less top end.

  3. #3
    RC Turnbuckle Jr. O.G.'s Avatar
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    I've never tried this so I wonder how much difference you'd actually notice.
    My Black & Blue Rally is faster than your color...

  4. #4
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    20t to 19t, u wont see the difference especially in top speed because lower the pinion better the acceleration and slower top speeds. There is no way he would gain top speed. If you lower the spur gear then it will add top speed. And again from 90 to 87, it will be 0.5-2 mph difference, not that much, why do it at all ?

  5. #5
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    Agriganosa - That's what I thought. Which is why I'm confused. I dropped him from a 20 T pinion to a 19 T pinion and now he can't do wheelies anymore, but all the sudden can keep up with my Raptor.
    So now we both have 19T P, but my Spur is 90T, and his is 87.
    I have 12 T motor and he has a 15 T.

    I've never messed with gearing before.

    Thanks for everyone's input.

  6. #6
    RC Turnbuckle Jr. rag6's Avatar
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    Changing the spur by 3 teeth is about equal to changing the pinion by 1 tooth. Are you sure his is an 87 tooth? If its the stock style spur, then it is either 76,83,86, or 90t.
    Wanna bash at Greenwood Bashplex in Pittsburgh ???

  7. #7
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    yaah it should be either 86t or 90t spur gear. Depending on the year of your car there is going to be a difference in spur gears.
    My friend bought his slash in 2008 with 90t spur and 12t titan setup. I bought mine in 2011 and i had 86t spur.

  8. #8
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    i bought mine in 2011 and it had both the 90 tooth and 86 tooth but the 90 was installed.
    Slash 2wd Vxl, ERBE; Crash N Learn

  9. #9
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    Quote Originally Posted by wmckay96 View Post
    i bought mine in 2011 and it had both the 90 tooth and 86 tooth but the 90 was installed.
    What i meant is the year the car was manufactured. We both bought our cars last year, but mine was newer and had different spur gear because it was manufactured that year, my friend bough his car the same day, but his model was 2008 lol, What a looser

  10. #10
    RC Turnbuckle Jr. rag6's Avatar
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    The old traxxas peg slipper setups came with 87t spurs. That was much older though.
    Wanna bash at Greenwood Bashplex in Pittsburgh ???

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