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Old 04-25-2012, 04:26 PM   #1
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Default Overgeared vs. Undergeared - Thermaled ESC

I have heard a few conflicting stories on gearing.
My motor is fine, the esc is hot
Mugen MBX6 Tekno V4
15/46
MMM and Castle 2200kv
4s
What direction is it best to go with the pinion?
Thanks,
E
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Old 04-25-2012, 04:40 PM   #2
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Usually means you are under-geared.
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Old 04-25-2012, 05:24 PM   #3
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Please explain why. I am trying to understand the reasoning.
Thanks,
E
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Old 04-25-2012, 05:34 PM   #4
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There is a few more things to consider here. What is the track condition, straight lengths, etc. Does it seem like you are hitting top speed early and asking for more? The gearing you are running is fairly common but on a large track it could end up being alittle low but I wouldn't think by a whole lot.
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Old 04-25-2012, 06:13 PM   #5
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My non-technical jargon answer, that usually works for me. Simple, if you can not hit full throttle on the track, you need to go down on the pinion. If you are constantly on full throttle and could use more at times, then you need to go up on the pinion. Electric motor system will not run properly at partial throttle like Nitro does. Electric should be geared to where you use all the motor gearing you have set up, but as mentioned, if you are constantly on full throttle, then need to go up a bit.

Mine seem to run best (Runtime, temps, performance, etc) when I am running between about 70%-90% on about half the track or more and hitting full throttle on several parts of the track.

EDIT Note: The castle 2200Kv system is a LOT of motor, I would guess you need to go down a couple teeth. I ran a 14T on my MBX6 ECO with a Tekin 2050 (Which is not near as much motor).
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Old 04-25-2012, 06:32 PM   #6
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The track is a medium sized 1/8 track. I have a tendancy to be a little trigger happy. I full pull before 1 jump and on the straight. Speed wise it has 10-20% more speed than I need on the straight. But as is said I have an on/off trigger.
E
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Old 04-25-2012, 07:19 PM   #7
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Lower gearing will put less load on the speed control.
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Old 04-25-2012, 09:58 PM   #8
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So I have 2 that say gear down and 1 that says gear up...
I think I will gear down and try to control the trigger finger.
E
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Old 04-25-2012, 10:14 PM   #9
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Usually a hot ESC is undergeared. So you could go smaller on spur or bigger on pinion. I do not have any experience with 1/8th scale, this is only my experience with sc10's.
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Old 04-26-2012, 04:03 AM   #10
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How does this equate to bashing? As there is no set limit on how fast you'll be going on a straight?
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Old 04-26-2012, 06:20 AM   #11
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Hot motor = under geared. Hot esc= over geared. IMO you need to gear down. What do you consider "hot"?
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Old 04-26-2012, 07:15 AM   #12
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Quote:
Originally Posted by rcgod View Post
Hot motor = under geared. Hot esc= over geared. IMO you need to gear down. What do you consider "hot"?
I may be wrong but the way I understood it was that if the motor was hot that it was over geared...the motor is under a big load trying to get the truck moving because it is geared toward being faster thus having less torque.
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Old 04-26-2012, 07:58 AM   #13
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Quote:
Originally Posted by rcgod View Post
Hot motor = under geared. Hot esc= over geared. IMO you need to gear down. What do you consider "hot"?
So motor will not get hot if you over gear... That's a new one on me.

If you thermaled then it should mean undergeared or batt not giving enough juice.
How long of runtime before thermal??

Your gearing is not off enough to cause a problem.

If it were me I would...
run it a few laps, temp the ESC/motor.
gear down 2 teeth, run a few laps, temp esc/motor.
Also try to gear up and run and check.
With three pinions and very little track time you can come to your own real world answers.
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Last edited by scwrod; 04-26-2012 at 08:09 AM.
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Old 04-26-2012, 08:24 AM   #14
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In my limited experience motor temp shows a bell curve with different gearing. Too high gearing it's working too hard and you get heat. Too low gearing and it's at max RPM all the time and you get heat. You need to mess around with it to see what keeps it happy.
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Old 04-26-2012, 08:52 AM   #15
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the way it has always been for me is that if i am geared to high, motor and speed control get hot.. If geared to low, just the speedo gets hot. just my 2 cents
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