Anyone here build a rear hub motor with 12g spokes & what tension do you tighten it to? I have a Juiced Bikes Cross Current with a 700c eyeleted double wall rim 12g spoked Bafang geared hub rear wheel & have recently had to deal with spokes breaking (5 so far). I have a park tension meter & have had the drive side at 130 Kgf & non drive side 100 Kgf.
Spoke Tension For 12g 700c Rear Wheel?
- Thread starter youth
- Start date
I'd get thinner spokes, like 13/14 butted Sapim (mine are from ebikes.ca but there are lots of places to get good name-brand spokes).
They will tension correctly without damaging your rim, where the 12g may not be able to--you might have to put such high tension on them that the rim deforms or cracks around the nipple holes, and then the spokes loosen, then you have to retension, etc. What happens at that point depends; if you ride it enough while they're loose the elbows take the force of supporting the rim and then they snap. :/
Use thinner spokes and you end up with a stronger wheel.
There's a lot of spoke size and wheel building and lacing threads around ES; I'd recommend looking around for those and reading them for more info on this. At least one is linked in one of the forum Sticky Index threads.
They will tension correctly without damaging your rim, where the 12g may not be able to--you might have to put such high tension on them that the rim deforms or cracks around the nipple holes, and then the spokes loosen, then you have to retension, etc. What happens at that point depends; if you ride it enough while they're loose the elbows take the force of supporting the rim and then they snap. :/
Use thinner spokes and you end up with a stronger wheel.
There's a lot of spoke size and wheel building and lacing threads around ES; I'd recommend looking around for those and reading them for more info on this. At least one is linked in one of the forum Sticky Index threads.
wesnewell
100 GW
If they're decent spokes and you're breaking them, I guarantee they aren't tight enough. You don't need thinner spokes, you just need to get the ones you have good and tight. It's really hard to get them too tight with most small spoke wrenches.
I don't know the quality of the spokes, but they held up for over 2000 miles on not the best of streets. I guess I will tighten them more then. The Park tension meter has a conversion table for the reading from the tool. My drive side were mostly 34 which equate to 130Kgf & the chart only goes up to 36 which is 172Kgf which I guess could be considered a limit.
wesnewell
100 GW
I don't have a gauge, but I've got over 15K miles on mine. Some rough roads up to 61.4 mph. And they've never come loose. After building my first wheel, I think I continued to tighten them after the first at least 5 rides.If I hadn't already had the right length 12G spokes when I built my MXUS 3000 wheel I'd have gone to 10G spokes.
I don't know any reason more typical bicycle spokes wouldnt' work without washers on that motor--on much bigger motors, like the MXUS "3K" or "3000" "45H", you would need larger washers or redrill the flanges for smaller spokes (I have this issue presently, on my SB Cruiser trike, and will probably be drilling rather than washers).
But even if you found that you did need washers, most likely you can just use some from the hardware store; I used some regular stainless steel washers from Lowes or HomeDepot (forget which) to lace up the rear wheel on my CrazyBike2, which also had large spoke holes.
If you were using a tougher rim then the thicker spokes could easily be properly tensioned and stay that way, but I really suspect that the reason your spokes break is because they get loose because the rim is not strong enough for that size spoke, and deforms.
If you check carefully in sunlight around the spoke nipple holes in the rim, you may find cracks, like these:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=12500&hilit=crack+nipple+rim&start=875#p796519
https://endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=625212&hilit=crack%2A+rim%2A#p625212
This is what happens when the spokes don't stay tensioned.
https://endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=752897&hilit=crack+nipple+rim#p752897
But even if you found that you did need washers, most likely you can just use some from the hardware store; I used some regular stainless steel washers from Lowes or HomeDepot (forget which) to lace up the rear wheel on my CrazyBike2, which also had large spoke holes.
If you were using a tougher rim then the thicker spokes could easily be properly tensioned and stay that way, but I really suspect that the reason your spokes break is because they get loose because the rim is not strong enough for that size spoke, and deforms.
If you check carefully in sunlight around the spoke nipple holes in the rim, you may find cracks, like these:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=12500&hilit=crack+nipple+rim&start=875#p796519
https://endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=625212&hilit=crack%2A+rim%2A#p625212
This is what happens when the spokes don't stay tensioned.
https://endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=752897&hilit=crack+nipple+rim#p752897
