@Skyart has tested 300kv reachers at 18s on the solos and reports that it’s stable, but if it’s really not workable then the worst case is that I have a suboptimal board and need to buy new motors to hit max revs.
The math says that 20kW should be enough to hit 75mph at the max with long gearing, but I’m expecting it to do sprints at 65 and hopefully 45-50 is thermally sustainable.
I wonder if it’s a mass thing because I didn’t notice much of a difference when I added linnpower adapters to normal 6 inch open gear set ups. I think that adds about as much mass as the extra teeth would
With a 300kv 14pole motor at 75.6V you have 158,760 erpm (erpm/60=2,646 Hz)
Samples per Cycle=15,000 Hz/2,646 Hz≈5.67
Imo you want to be at 10 minimum otherwise the risk of an overcurrent fault is high
I would like to respectfully ask why @Flyboy don’t use remotes, is it because of a physical disability or just innovating in a very risky way?
anyway that leg throttle looks cool! but it’s a lot of work to use and I would be scared to physically attach myself to the board. my 2 cents
I think it’s explained in the thread. He has a condition where his hands will hurt if they hold the same position for too long like when using a remote.
I got to try it myself in person and it works a lot better and it’s a lot more intuitive than I was expecting. It’s not what I would use but I could see why he likes it
It’s 245Kv and that’s only true while free spinning on the bench. Under load, the battery will never be higher than 4V/cell and the motors top out around 90% of the free load speed.
72v * 245kv * 0.9 * 7 pole pairs = 111keRPM which gives 8.1 samples… Ok I see the point still.
It’s just garden variety repetitive strain issues. I’m fine now, but I use things like voice typing and hands free skateboards so it doesn’t happen again.
The rider is not strapped to the board, because the telescoping section just pulls straight out and tanks the kill switch. Separation from the board triggers the brakes automatically because the VESC is set to [current control no reverse].
There was an incident with the version 1 kill switch where it broke and threw me from the board, but there have been no failures with the current Legstick version for the past 2 years. It’s very safe IMO.
Fun fact I’m the reverse, I cannot ride remote boards, I’m like a newborn deer on the edge of falling over 
Spent a while on a work trip that wiped me out a little, but I’m back and finished modelling the extension brackets. I have a rough idea of how much material I need to order now. Next is to model the trucks and pull the trigger.
I’m also gonna order the gears at some point this week. They’ll be 2x 3/16" layers of hardened and tempered 4140, mod1.5 109T, fits MBS pattern and Jackson hubs specifically. The cost to me for a gear plus a 75-90mm CC motor mount is about $170 per set at QTY 4, but if someone else wants another set of 2 it goes down to about $160, if I end up ordering 10 it’s about $150 per. If anybody else is looking for a Big Wheel specific open gear setup and wants me to group buy these, HMU. 
It uses this spacer with a 12x28x8 bearing inside the print, plus a 12x28 flange bearing in the gear.
Kart Spacer Block.stl (1.1 MB)
You’re not worried that all of the folded steel bits will flex?
Where and how do you mean? Everything flexes.
I’m just armchair engineering over here!
Not enough folded steel, clearly 
i have no experience with what you’re doing, just seeing the almost skeletal design makes me wonder if you are in any way concerned about it’s strength
If you don’t skeletonize a steel structure it’ll be heavy as balls. I’m trying to make it in a way that preserves lateral and torsional stiffness for good handling, but creates vertical compliance so the whole thing doesn’t snap when it hits a pothole.
