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  1. #1
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    Heat question, but undergeared?

    Is it possible to get heat issues from under gearing a motor?

    My Slaja bug slash is running
    a cheap Orion Method R 17 turn motor
    new 6 cell 4500mah battery.

    First gearing was a
    16/86 and motor temp got to 182

    A little too hot, so I thought I would gear it down to help.

    So I went to a
    16/90 and then the motor temp got to 233

    Both runs were general bashing in the front yard with my kid driving on half grass and half asphalt. This is to seperate days and about the same temp outside.
    So was my first gearing already undergeared also? and I should have gone down on the spur to an 83t.

    Let me know what you think.

  2. #2
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    Are either the battery & esc getting hot also?

  3. #3
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    Quote Originally Posted by rugruner
    Are either the battery & esc getting hot also?
    Both esc and battery were at normal temps, nothing unusual.
    I might try to get and 83t gear tomorrow and see.

  4. #4
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    I have the same problem. I have a rusty, a bandit, and a slash. In the bandit, I have 26/76, slash is 17/86, rustler is 23/90. They all get hot very fast. I do not have a temp gun, but I cannot hold my finger on the motors after 10 minutes of street and light grass racing. Also, battery and ESC were fine.
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  5. #5
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    Undergearing would generally not make a brushed motor overheat. I would try both sets of gearing again and run it up and down the pavement for 5-10 minutes on one set and record tempreturs.
    Run the other gearing at exactly the same battery and the same times and record temps.
    Let me know the results as i'm curious to the temps of both gearing when driving up and down the st

  6. #6
    RC Racer
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    i would say that undergearing it makes the motor spin faster all the time which would definelty build up more heat. the faster the motor spins the more heat is created. if you have it geard properly the motor should get warm but not to hot.

  7. #7
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    I have run many set ups, with many battery, esc, Tire & gearing changes. With the Stock XL-5 w/12T Titan, Stock Slash Tires/Wheels a Team Orion 6C 4500NIMH , I've found that Gearing 19X86 gives the me the best all around performance and temp's. ESC & Battery are around ambient(90'ish) and the Stock 12T Titan end up around 155 to 165'ish after a normal Back Yard Bash, or a four minute test session on the Track...

    I have also experienced increased temperatures while testing undergearing....but this was after extended runtime,,,,,,,generally just the motor temps, esc & battery do not seem to be affected the same way?????

    fgbiv





    Quote Originally Posted by Born2Race18
    i would say that undergearing it makes the motor spin faster all the time which would definelty build up more heat. the faster the motor spins the more heat is created. if you have it geard properly the motor should get warm but not to hot.
    Slash 4X4, Slash 2WD, E-MAXX 3905, Extended Pede

  8. #8
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    16/90 is not under geared for 17 turn in a slash. The rule of thumb you hear around here a lot is 2 teeth less than the turns of the motor. That typically gets you closein the pede and rusty. The Slash is heavier and bigger so it's harder to push. Running a 17 turn i'd start at 14/90 and see how your temps look. Also keep i mine that grass is the killer of motors.
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  9. #9
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    Well I killed the motor today.
    I went back to the 16/86 gearing since that gave me the best temp at 180.
    My kid was running it in the dirt, lots of wide open throttle. After about 8 mins of running the motor wire melted off. And the temp read 282.

    I've been running this 16/86 gearing for awhile and just now had these wierd temp readings.

    But now the motor armature has about and 1/8 or more of back and forth play.
    Now I'm thinking my motor was on it's way out and thats why I kept getting different temp readings. I always oil the front and rear bushings almost every run too. I've never had this much problems with electric until I got the slash. My brushless one has no probs, just the brushed.
    I think I have a spare Orion Method motor to try.
    Time to get another Havoc 8.5 for this one.

  10. #10
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    No real surprise that the Slash is giving you temp problems. It's a little heavier than what most people are use to dealing with and having to push that big body through the air is harder on the motor. Brushless is the easy answer but if you plan to run another brushed motor then drop down 3 teeth below the turns of the motor. That's a good place to start.
    My mother
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  11. #11
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    Post

    Quote Originally Posted by john01374
    No real surprise that the Slash is giving you temp problems. It's a little heavier than what most people are use to dealing with and having to push that big body through the air is harder on the motor. Brushless is the easy answer but if you plan to run another brushed motor then drop down 3 teeth below the turns of the motor. That's a good place to start.
    ya Brushless is the way to go but if ya don't have the $ save up lol
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  12. #12
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    what is a temp that one should look for when racing for an electric motor?
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  13. #13
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    The brushes might have been worn as well. This causes poor efficiency and that generates more heat.
    Another possibility is the motor was clogged up with carbon and dust inside. This acts like an insulator and doesn't let heat escape

  14. #14
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    If you are going to run a brush motor in the slash with no problems, stick with a 19t or higher. But brushless is a way to go.
    Simply the best. The beautiful Traxxas SRT and TCP

  15. #15
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    travmac79 - I gear the motor to run in the 150's. When the temps start creeping into the 160's i either change my gearing or set the truck aside for a little while. Some say motors are good to 200F but I've seen motor performance degrade after being run in the 180 / 190F range.
    My mother
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  16. #16
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    Leave the motor under 150 and you'll be fine. I've run at the track on a stock setup with 2S LiPo for 10 minutes and I was still under 150. It may be that you have better traction on your street and then running in grass will really heat it up. Brushed motors can't get as warm as brushless so watch your temps, if you keep them under 150 like I have, you should be fine. I only have 25 runs on my Titan still but it runs very well.

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