What's the general consensus about gear drive?

I like the idea but I’ve heard that inrunners can have heat issues and don’t have a lot of torque (very high kv) I’m curious on how it performs on your build

Also small wheels don’t leave enough room for covers which I would prefer to have with gears

it depends on whether the idler is used in the calculation of the gear ratio. if not, the idler is just there to transmit the “drive” and also to extend the total gear center distance.

i may be wrong, but that’s what i see/think it does.


Right right. Isnt computing torque via gears also dependent on the distance between the pulley and the motor? I’m taking this from a topic I’ve discussed with a friend so I may be completely wrong lol

Yes that’s wrong, lol. Distance has nothing to do with ratio. It’s just the difference between the motor gear and the wheel gear. The idler gear doesn’t even affect it overall.

Edit: Just saw you were talking about torque, not specifically ratio, so I can’t actually say that for sure. I just know about calculating the ratio. I know with belts there is many different things such as the width it the belt, but for gears, I’m not sure if that matters as much. I know they transfer torque much better than belts, but I couldn’t get into specifics just yet :smile:

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Oh sorry didn’t mean to misinform so just disregard what I said haha. So its simply for allowing a smaller gear on the wheel which increases the clearances to what you stated earlier? So no actual or significant impact to the torque delivery/output?

The ground clearance and the motor from hanger clearance are the main reasons for the design. It’ll probably take a bit of testing prototypes to determine just how the smaller gears transfer torque.

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Okay at least I got that much lol, nice work eager to see how they fare in real world use. I should’ve looked up @MoeStooge’s build sooner lol

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@uigiroux Any downsides with an idler gear beside adding complexity to calculations?


Additional moving parts means another point of maintenance.

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I can’t say just yet since we haven’t made it yet, but in terms of calculations, the idler gear actually doesn’t affect the ratio from the first and last gear I found out. What’s yet to be determined is if it’ll be better to have an idler gear that’s exactly in between the sizes of the other two gears to keep equal torque applied to both sides, or if it’ll be better to just have two of the gears be the same size. All will revealed after testing :slight_smile:

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I’d also like to point out that @idea has some very awesome looking gear drives that’s he’s made and been testing for awhile now. I’ve messaged him a few times trying to get him to sell me a set, as his do work with PU wheels and so far as I’m aware they don’t have clearance issues, but I can’t say one way or the other as he doesn’t want to make claims without the testing to back it. These look very nice though!




He has a few other drives in the works as well, though this is the one I’ve been most interested in.


Stunning! And the whole assembly is extremely compact with the 50mm motors that’s something I’d want for a compact/lightweight build! Is he using POM or steel?

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The gears are POM, case is steel.

Scorer for Derby days had Avg speed @ 46mph (74kph) for the 4.6 miles race on 56mph setup. Esc temp 135deg f (57c). Inrunner Motors cool enough to grab. Any doubts about the tourqe and speed if inrunners In the same package, the vid should clear it up.



Yeah I messaged him about it and he also gets amazing range its crazy. Very efficient from his uses


Seems like a very good option for compact builds as well I like the small diameter of inrunners and I believe you can run them with good performance just with a 4s right? How much current do they draw? I’d be curious to see if tiny 4s packs could sustain this setup that’ll mean insanely compact and light setups. How is the noise?

Not sure if the motors can affect the noise much when used with gear drives

Yeah I think unless you’re dealing with very well engineered helicals, such as @nowind has done (damn those are so crazy silent it’s incredible!) the louder sounds will be coming from the gears, not the motors… If for some reason the motor is noisier, you probably have bigger problems, lol :laughing:

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I’m curious how the clearance is with 63mm diameter motors in @idea gear drive…

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I’ve only seen photos of them reverse mounted though but they look really low to the ground or it may just be the perspective of the camera that may be doing that. Im all for lowered decks though for better stability