56mm planetary gearbox

Just got this gearbox from aliexpress.
I like that it is same diameter as 56104 motor im planing to use on my build.

Cant decide sould i go with aluminum tube around motor and gearbox or just waterproof motor and gerbox and leave them without tube.

Also did anyone used this gearbox for efoil build?

Have u checked input rpm?

Motor will spin 18000 on full throttle and gearbox is rater up to 19000…

I,d put it in tube with id 56/od 60.
It is important to choose a solid coupler, best to take one with a key.

I was planing to use flexible jaw caupler.
Why do you think soild coupler would be better then flexible?

Flexible jaw or dual disk coupler with proper bearings to support the prop shaft is probably your best bet. Or are some people relying on only the gearbox bearings to support the prop? :open_mouth:

either angular contact bearing or thrust bearing to take the load oft the prop. The bearing oft the gear is not built to take axial load. For the couplers search the forum, many failed.

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What if i change bearing in gearbox with angular contact one?
Could that work?

Do you have a link to this gearbox?

HRK 159.94 7%OFF | Ratio 3.6: 1 / 4.25: 1 planetary reducer 56mm Round input flange for DC motor with motor shaft diameter 6mm or 6.35mm or 8mm

Its very difficult to say whether changing the bearings would work for you. Its not optimal in any case. I would recommend to use a flexible coupler, such as a dual disk coupler and then use two bearings to support the output shaft. One of them should be able to take axial loads. Maybe use a tapered roller bearing + normal deep groove ball bearing. That should provide a mechanically robust setup.

Are you seeing 18000 RPMs using the VESC tool or is that a calculated max RPM?

What types of RPM’s are people seeing on their setup? Mine is nowhere that high.

I dont have VSEC…
18000 is caclulated value, no load.

Im lucky.
I had this coupler im my stash, but wasn’t shure what shaft bore was.
Im lucky it is 12mm fits perfect.
It is steel :).
Just need to replace srews…

Did you end up using this gearbox? Did you go with another? I am looking into a build and am hoping you can share your experience.

Thank you,


Sorry my bulid was a little bit postponed. Corona and all that stuff.
Yes i am still planing to use that gearbox for my setup, and cant give you any opinion coz i didnt do any real test with it. Motor and propeller are spinning fine without no load.
I dont know if that informtion helps you in any way…

I ended up getting the gearbox and it works fine

Thanks for update.
I didnt test mine still.
Did you finished your foil and done some tests in water?

Got the same gearbox as a backup setup, going to test it soon.
I had to separately buy " 1M 15t " 8mm bore spur gear for everything to sit flush.
Marked and drilled the cover plate by hand

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Hi, and what are you going to drive with this system? Thanks