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  1. #1
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    Stampede Studdering Start

    Hope you folks can help me where my local hobby store could not. Just dropped in a new motor and drive gear. I think I got the motor tension and gear spacing right (my 3rd motor). Now the truck stutters on start. Sometimes so bad it won't get to speed, other times is stutters a few times then all's good. Truck feels great once it's uip to speed; just get this stutter5 start.

    Here's video of stutter in action: https://www.youtube.com/watch?v=fepF...ature=youtu.be

    All batteries are all fine. No stuttering if I hold it off the ground to take all tension off the wheels.

    Why do I get this stuttering on start?

    Thanks!!

  2. #2
    RC Champion SlashMaxx4x4's Avatar
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    Is there any binding in the drive shafts? (Center or axles)

    Sent from my SM-G930T using Tapatalk
    "Gone racing"

  3. #3
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    How do you mean 'binding'? Everything turns by hand with nothin blocked. When I roll truck by hand I can feel it's not smooth. The drive train 'rattles', or catches a little, as I roll it. I see the center driveshaft turning but not sure if it should be totally smooth.

  4. #4
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    Geared to high? Maby not enough punch in the battery , c rating to low . To less amps from the esc?
    Stampede 4X4 VXL
    Rustler VXL

  5. #5
    RC Turnbuckle Jr. Petertje60's Avatar
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    What you experience is called cogging. Not something to worry about a lot. Can be solved by lowering gearing or using batteries which can deliver more current.
    Nobody is born with experience

  6. #6
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    The gearing/pinion is stock. Batteries are replacements the hobby store sold me: Onyx 3000mAH, 7cell,8.4v. Perhaps I should try new 4000mAH battery?

  7. #7
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    You have to remeber that the battery can delivet the amps you ask to get the car running. In small explained , it is the c rating that has to deliver the punch to move a car. 3000ma on 20 c means that it can deliver 60 amps on burst . The amps will raise by weight , drag , weel dia. , motor etc . Get a battery that has 20 a 30%more than the nominal amps of your motor.

    I ride on an5200ma 50c to punch on start
    Stampede 4X4 VXL
    Rustler VXL

  8. #8
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    Looking around web ... How do I find the 'c rating' on a battery? It's not a common spec from what I see ...

  9. #9
    RC Turnbuckle Jr.
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    Quote Originally Posted by RCLakin View Post
    Looking around web ... How do I find the 'c rating' on a battery? It's not a common spec from what I see ...
    For Lipos itís super common. There is no C standard. Buy a higher amperage battery and lower your gear ratio. You could do these one at a time.

  10. #10
    RC Turnbuckle Jr. Petertje60's Avatar
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    I see that you are using NiMH batteries. Those can probably not deliver the amount of current that you car wants. In general, lipo batteries can deliver much more current than NiMH ones. Brushless motors (which you are using) are most of the time used with lipo batteries.

    The C rating of a battery (you will find that on lipos, I never saw it on NiMH batteries), gives a rough indication about the ability of the lipo. Multiply it with the capacity of the battery and you have the current that the battery can deliver (a 5000mAh 40C delivers 40x5000 = 200.000mA which equals 200A).
    Nobody is born with experience

  11. #11
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    Like Petertje tells , You need the punch of a lipo to get the pede running . If you want to use your NiMH battery , you have to look to reduce weight or drag or lower gearing so the amps to get rolling arent to high . Otherwise , get yourself a good set of lipos.Try not to be cheap because of you go for a lower C rating , You can damage more than you think , like the battery itself or the esc .

    Ex: Im gonne put a motor in my pede with a burst of 1200W on 3S . So this is 1200 / 4.2V per cell = +/-95Amps on 3S

    Same on 2S means : 1200W / 4.2V per cell = +/-150amps

    This is theoretically because the amps are gonna be higher because of weight, drag , tires size , gearing so thats wy i tell you to go 20 a 30% higher on the batterys.

    You see the big difference between 2s and 3s what means you have to see that the battery can deliver this amps and that were the C rating comes in .

    Also , Be sure your connections are all OK and you minimize the resistance , Ohm Law
    Stampede 4X4 VXL
    Rustler VXL

  12. #12
    RC Competitor
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    Sounds like a fault with the ESC. I'm having the same problem with my Slash.
    Gonna try a Hobbywing ESC.
    JES

  13. #13
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    Did the stronger battery work for you RClakin? Wondering if this issue got resolved because I had similar problem as well.

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