You are right!! Imeant 10:30 etc in the first place!! Sorry for that!
Thank you very much! I did not know about 70% efficiency for tires. Also i made a mistake, i meant 10:30 or 1:3 etc in the first place.
a 12s4p 30q can totally do 15miles you just got to take it easy, also your efficiency heavily depends on tyre pressure
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This would be the gearing ratio I choose if I need to put 70% efficiency because of the tires:
I think that is enough torque for a mountainboard and I will decide if I get a battery that has more that 12 s groups to boost speed afterwards.
Please feel free to comment!
imo it’s way better to run higher kv motors and have a larger gear ratio,
personally i’d run a 1:5 gear ratio 170kv motors
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Are there even 36T pulleys for MTB hubs? That seems really small, and you’re probably going to need a custom pulley to reach the bolt holes. Also the Wh/km seems a little optimistic for pneumatics.
Thank you very much for your reply! That will make the gear drive more noisy, so I prefer going with 90kv motors that will also support up to 18s.
I will use 3dservisas gear drive wich comes in 1:2.6. I just lest wh/km to default values, I do not know how to calculate that. Do you know?
Battery and motors are more expensive than gears as far as tuning your setup goes.
On my 8" tire setup, I get on average 25 wh/mile which is 15 wh/km. Pushing it hard through the woods or rough terrain makes it go way up to 25 wh/km and beyond.
I’m also a pretty light guy at 155lbs
I also average about 25 wh/mile on 6 inch pnuemmies. I’m also light, but it’s pretty hilly around here
This is a street board though
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I second this
I’m usually heavy throttling on my 6" pneumatic street board and get that so good to know.
@JulienB your urethane build will have muuuch better efficiency/lower consumption than the mtb as I’m sure you’re aware.
Thanks for all your input! Very informative! Yeah that is why in the end the urethane board will have the 12s4p battery.
also i’m pretty sure most motors will handle whatever voltage you throw at them (amps cause the heat i believe) and i don’t think a higher gear ratio causes more sound, gear drives are hella quiet, it’s when you use compound drives that the sound builds up
I am sorry to derail the thread a bit 
There is two reasons why this isn’t true. The first is that the bearings won’t like to rotate so fast all the time, but this can be mitigated to a degree by changing them out with higher quality ones.
The second reason is that in the motor there are two kind of losses. One type is called copper loss, thats basically the energy dumped into heat because of the amperage and this is not influenced by the rotational speed of the motor. The other type of losses are the iron losses, and those are getting worse as the motor spins faster and faster. I have not seen any tests comparing iron losses and copper losses in esk8 motors, so I don’t actually know how bad iron losses are… But they definitely exist, especially if you go with too high voltage and kv. The torque that the motor puts out is also a factor in the losses, but lets ignore that now.
This picture below showcases both losses for a random motor, obviously for the motors we use the numbers would change.
Sidenote, somewhere I read that the outrunners we use are the most efficient around 10k rpm. Probably thats the point where the losses are balanced out?
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I have tried to get the discussion about the “magical erpm” limit going a few times but always end up getting “I believe” answers and assumptions with no data proving anything but a lot to think about.
Some discussion here I’d love to get kicked back up 
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tbh the motors we use are pretty damn small, and losses does not equal not able to use higher voltage. if you looking for efficiency the drive train should be the first place to look at.
I agree, but shouldn’t it mean more heat because of more losses?
due to the size of the motors we use the losses are pretty small. running higher voltage with a higher gear ratio would keep the motor cooler then a low voltage high amps (torque output the same)