Wholly FAAAAAK 2500 bux for a 4535 handbuilt motor… @hummieee let’s make bank!
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I got a “geared hub” bike motor I put on this little bike which has a planetary gear in the hub. It’s pretty quiet and said to have more power to volume n weight then a standard hub motor. When people say it has more power or torque than a standard hub they almost always mean efficiency and really our little motors show we can get huge peak power or torque regardless if we’re ok with less efficiency.
I imagine in a skate wheel or DD any kind of gear style above would amount to few and little gears that would get eaten quickly and expensive to make to begin with and add another thing to possibly break.
I don’t see why those Astro motors are so expensive and they don’t even tell the detailed specs. The cobalt magnets makes me think the motor is for really high heat and seems kinda silly n they don’t have the same strength as neodymium. And then it says the winding insulation only does 200c. That’s nothing special and was using that. Got 240c wire now
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Stupid question, isn’t having a direct connection to the wheels the whole point of direct drives?
Gears:
Pro:
- low mechanical losses
- allows for higher KV motors with higher electrical effeciency
- allows for much larger motors and better ground strike resistance
- Lower maintenance than belts. Typically only requires addition of lubricants.
- moderately flexible (different motor size and Kv options)
- not likely to be seriously damaged by ground strikes
- mounts to normal trucks
- Mechanically durable and typically does not require truck alteration
- Practically unlimited power transfer ability (for our usage) No belt skip, ever.
Con:
- nosier than DD (Noise varies by gear type. Some are reasonably quiet, and some are very loud)
- takes up extra space under the board or sticks out the back
- more moving parts
- not as flexible as belts
- typically can only mount to certain trucks
Direct Drives
Pro:
- Takes up less space under the board
- Most mechanically efficient design (effectively equal to hubs)
- less moving parts, less stuff to go wrong
- near zero maintenance
- Quietest by far.
Con:
- Has to be mounted directly inline with the wheel
- Ground clearance issues because of the above
- Requires specialty trucks with much longer axles.
- Very fragile if not designed exquisitely. (look up metasurf for an example)
- Prone to axle bending (see above)
- Motors are specialty and only designed for one system
- Motors will eventually die from ground strikes
- Not flexible at all. Pick one of two Kv choices (if that) up front and forever hold your peace.
- Not powerful enough for serious off-road use
- Weak regenerative brakes at low speeds. Requires active braking for hard stops
If you add gearing of any variety to a direct drive, you gain one positive, lose all the existing positives, gain a bunch of negatives and make some of the existing negatives worse.
- no longer has weak regenerative brakes
- no longer the most mechanically efficient, now equal to regular gears
- no longer beats gears on moving part count
- added gears might require maintenance
- will take up more space for a given motor size
- no longer the quietest and likely to be equal to gears
- now it has a whole bunch of small moving parts right next to the ground
- potentially has even worse ground clearance depending on size of planetary drive
- even more specialty (fragile) parts
- you are still massively limited in the size of motor you can mount
With this in mind, why would you ever want to have a planetary direct drive? Spiral bevel, helical, herringbone and even spur are significantly better.Not only that, you can’t even call it a direct drive as direct refers to the fact the motor is directly mounted to the wheel. A hypothetical planetary “direct” drive would be more accurately called a planetary axial drive as the motor is mounted axial to the wheel.
Tl;Dr, Planetary “direct” drives seem interesting but are actually awful on nearly every level.
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Belts tho 
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Great gear video. Explains why gears of the same module and pitch can (and should) be slightly differently shaped. 9:07 gets into it specifically.
Same pitch and module gear, just different tooth count:
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Why do we always run the big gear on the wheel and the small gear on the motor? Why not the opposite?
Shouldnt really matter but would give more clearance in spur gear drives and other gear applications
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The bigger the motor gear, the more stress you are putting on the motor and the shaft
Try it on a calculator and you’ll see that it does not produce any good results. Worse than DD for torque. You want that reduction in speed an increase in torque that the normal way of gearing gives you.
The only reasonable way I’m thinking this would work is with a @moon-like 4GD geared down then up. Interesting thought but if you need clearance you should just be using massive tires/wheels and get rid of the complexity, cost and weight.
You can just use 3 gears and achieve the same thing
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ah the amount of beans I just got on my keyboard is not ok
I didn’t think about it that hard 
I referenced your project as the only 3+ gear drives I can think of besides whatever @Arzamenable has going on
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