Yeah I meant just the 8mm bore portion that the pulley can sit on Edit: sorry confused myself for a minute there, yeah keyway is 19mm long, 8mm shaft portion is 25mm
wth those are tiny 
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Hehe yeah, donāt need to be any bigger 
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This have no logo right?
Yep no logo or writing of any kind
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The keyway and pulley are much longer than the key. Conceivably the key can be pushed out towards the end rather than centered along the keyway of the pulley as pictured there.
With the forces from the belt this could cause premature wear on the shaft/bearings.
If you cut/finish them yourself, they run to about 12c each from keyway stock, excluding the very expensive time of course.
Iād cut them a 1/2" longer & take the resulting financial ruinā¦thatās just me, you know to be safe. Satisfy the keyway with the right key.
2 of those 12c keys and loctite 
Now hold out your hand!
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Once the key and pulley are on, nothing is moving, having a short key has 0 impact on bearings.
Average Key Length Standard, inbalance avoidance, given these brushless motor turn at extremely high rpm there is a case for keeping them in balnce otherwise you could fatigure the shaft/bearings.
Measure the full length of both keyways(pulley keyway and shaft keyway, add the two dimensions together, and divide by two, then x .95
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Youāre thinking too much about it lol, it really has no impact
Iāll hang onto the accepted practice and thinking too much, but thank you for your opinion 
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Iāve been running short keys for a few months now, if thereās anything to consider the smaller the key the better, since youāre adding less weight to one side of the shaft
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Itās not as simple as that, really, what is best is a shaft with pulley and key on that is perfectly balanced as it spins @10k rpm, that is what avoids wear, Iām not saying it will explode and impode the universe and yes your millage will undoubtedly vary, Iāve never seen a thread with a worn bearing or shaft ever.
But if you are not interested in the accepted engineering practices/stanards, then thereās nothing more for me to say, so avoir thread!
On the plus side Iām looking forward to these motors, thanks for takling to Cindy/Sandy/Bella or whomever in Maytech or Maytech wannabe, thatās a particular pain I was looking to avoid.
But keep your keys for the next buyer!
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Dude it makes absolutely 0 difference whether the key is closer to the motor or further away. Whether it spins at 1k rpm or 10k, itās exclusively a twisting force and thereās 0 lateral load caused by the key. Even if the key was three feet long and a metre from the motor it would still be a twisting force on the shaft, except for the centrifugal force. The only thing having a short key towards the end of the shaft (away from the motor) would do is try harder to twist the shaft enough to shear it or destroy the key, which is exceedingly unlikely.
How close? You can add a couple extra spacers inbetween the wheel pulley and the trucks to kind of scoot the wheel out a bit more.
Looks like there is space between the motors too, so you could add spacers inbetween the motor and the mount.
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I have a couple threads on the trucks that I may be able to add a washer. I plan to 3D print a spacer for the motors as well. There is a small chance I will not have to hack the motor shaft. I have been slow building this because ultimately I am waiting on Focboxās to arrive.
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thatās very informative I like how physics work on your planet
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more weight on 1 side? what? Remember the key fills in the space in the shaft but also the pulley. If anything filling that space completely is what will cause the best balance. U must include the pulley in that balance
Hereās one I prepared earlier. Iāll be happy to be wrong if you can refute that 
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