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  1. M

    Plywood for suspension?

    Thanks for the inputs! Sounds like I could start out with plywood and if the thing is a success and the plywood proves to weak, it could be upgraded to fibreglass. Or inforced with it.
  2. M

    Plywood for suspension?

    I'm considering building a lightweight, low power ( 2 x 3 KW) kart-like vehicle. Gokart wheels, independent rear drive shafts, dual belt drive BL motors and dual ESCs with steering vectored "electronic diff". Each motor drive, shaft, brake and wheel bearing mounted in identical stiff...
  3. M

    Notes on my first build, rear belt drive

    markz, sorry for the delay. I'm about 210lbs and the weight added by motor/drive/ESC/battery is very low, like 4lbs.
  4. M

    Notes on my first build, rear belt drive

    A little update: Currently running the bike with an 4258mm NTM 500KV motor on a single 6S pack (the 3 x 3S packs were just too troublesome to charge - one at the time).With a 16T sprocket the gearing is something like 16:780 or 1:48. I have enlarged the tensioner bearings for lower friction and...
  5. M

    Convince me to upgrade to a sine wave controller.

    I'm using a VESC on a low power belt drive MTB (https://endless-sphere.com/forums/viewtopic.php?f=3&t=97578&p=1434140#p1434140). I've tried 3 or 4 different motors and voltages ranging from 4S to 9S. And I've also tried switching between FOC mode and the normal "PWM" mode. In all cases I've...
  6. M

    Notes on my first build, rear belt drive

    My VESC is equally cool in both modes. I can't really feel any temperature increase. I'm afraid that I don't have access to an oscilloscope that can sit on the bike while driving...
  7. M

    Notes on my first build, rear belt drive

    Thanks - Actually I have just replaced it with a metal pull spring :)
  8. M

    Notes on my first build, rear belt drive

    On FOC efficiency: After having run different motors in different modes (FOC/"BLDC") and configurations, it seems that the motors always run at a higher temperature and with lower efficiency in FOC mode. I may be loosing up to 20% range in FOC mode. I wonder why? Maybe because I'm running the...
  9. M

    Notes on my first build, rear belt drive

    The 25T brass pulley arrived after quite some shipping time. Meanwhile, some othe stuff also arrived, including 5 pcs of new 1524mm GT2 belts and a 280kv 5055mm SK3 motor: It was on sale ($30) at HK, so I grabbed one to get the current down (low KW = equals more cells = lower current), as my...
  10. M

    Notes on my first build, rear belt drive

    I passed the 100km mark today, and celebrated by replacing the 20T pulley with a fresh 16T Alu pulley (the only one available with the brass pulley sitting in a slow boat somewhere). I also swapped the 4240mm 650KV motor with a 4258 mm 500kv and went from 4 to 6S. The 10mm GT2 belt looks rather...
  11. M

    Notes on my first build, rear belt drive

    Pulley wear at 70km: Still no slippage, but it doesn't look like it will make it past 100km. Waiting for the brass pulley to arrive. I wonder what causes the wear: Just the fibre inforced belt, or dirt particles picked up from the non-slip surface or from the street? 3M or 5M belt and...
  12. M

    Snow Beast Refurb

    hahaha :thumb: Back to topic: I couldn't muster that kind of enthusiam for a rusty bike unless it was very, very special. And did you consider the effect of galvanic corrosion when bolting together steel and aluminum? Put those two metals together, add salt water, and the aluminum will wither...
  13. M

    Notes on my first build, rear belt drive

    I've done 60km so far. The belt looks nice and there is no slipping whatsoever, but the 20T alu motor pulley shows sign of wear. It has rotated 900.000 times now, so thats perhaps to expect. I have ordered a 25t brass pulley to better cope, but going 5mm module belt is probably a better solution.
  14. M

    Notes on my first build, rear belt drive

    My current tensioner does not allow braking. It will only make the belt slip on the motor pulley. To overcome this, I'm designing a dual way tensioner: and brake mode:
  15. M

    Notes on my first build, rear belt drive

    1mm wire through dual holes around the spokes. In 8 spoke positions I cut small recesses as half of the spokes are outside/higher than the other 8. This way, the rim/ring rests nicely on 16 spokes. I don't expect to transfer monster power this way, but it seems to cope effortlessly with the...
  16. M

    Notes on my first build, rear belt drive

    Thanks - good information. I used the 6Ah consumption, 27min drive and 15V to calculate. The return drive was a more moderate 4400mAh, and if I use 14.4V volts instead of 15V, I'm getting below 150W. More like 145W. Now subtract the belt loss (5-10%), a little higher speed, and my knobby...
  17. M

    Notes on my first build, rear belt drive

    doc, falcon, slowco, thanks :D Efficiency The recharge was 6Ah, or 6004mAh, not 600. The 600mAh is per km, resulting in the 200W. I just finished recharging after the home run, this was 4400mAh for the 26min drive, or 152W average power, so the wind has indeed an effect. 3D belt wheel I...
  18. M

    Notes on my first build, rear belt drive

    Just wanted to share a few details on my first build: - Scott Aspect MTB - 3D printed 440mm diameter belt wheel, fixed to 16 spokes. No teeths, just friction tape - NTM 4248mm 650kv outrunner w 20T GT2 timing pulley - 10mm wide 1524mm GT2 belt - 30:1 gear ratio - 4S 16Ah Multistar LiPo pack -...
  19. M

    About to order from NKON.nl - What to expect?

    I ordered a couple of 18500 cells 14 days ago, and they have not yet arrived. Usually shipment from the Netherlands to Denmarks happens in a few days. I suspect the packet is lost or was not shipped from within the EU. It's a shame, as I'd noticed they also have the NCR20700 4250mAh, but I want...
  20. M

    Left side freewheel sprocket adaptor

    Also my question: Is that a belt drive? Thats my idea :wink: I'm looking into doing a low power, parallel, free wheeling drive with a 6 or 10mm timing belt, using a 300-400W low-kv brushless RC motor. I figure a 1:20 reduction is required to maintain a reasonable bending radius on the motor...
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