I'm considering treating myself to a road / tour / gravel bike maybe the Croix De Fer 10. Mostly for cycling on poor quality roads and tracks, sometimes for longish rides (50-100 miles). I'm also considering fitting a kit to the above bike. Rear wheel preferably. I would like to be able to swap out the motor wheel and ride with the original wheel at times. To this end I would like as many of the kit bits to live in a removable crossbar bag. I'm happy to just have a throttle so even the led display is not needed on the bars. Everything could then be easily removed when not needed. The motor wheel would be fitted with the same cassette and disc rotor. Would this work? I have fitted another kit previously but I'm no expert so would like something fool proof . Given these requirements, what would you recommend?
Genesis Croix De Fer
- Thread starter Jonah
- Start date
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Deleted member 4366
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If you're going to swap out the motor wheel, you'd need a front motor unless you want to adjust the gears each time you change the wheel because the spacing will be slightly different.
If you put the controller and battery in a frame bag and use velcro straps for the motor cable, you'd only need to disconnect the PAS and LCD cables when you swap, which is no big deal. I'd use a 260 rpm Q100H or a 201 rpm Q100H at 48v. That will give an assisted speed of about 22 mph. At 48v, you get 30% more torque. If you're sure, you want to restrict to 15.5 mph, then use a 201 rpm motor at 36v.
For a controller, at 36v, it's the S06S from BMSB, and at 48v, it's one of these, which is the same but 48v:
https://www.aliexpress.com/store/product/Free-Shipping-36V-250W-48V-350W-Controller-LCD-LCD6-display-PAS-Set-for-E-bike-kit/738588_32834523159.html?spm=2114.12010612.0.0.7e293d38ddcB77
The new tiny Xiongda motor is much lighter, and it still gives pretty good power and is very cheap, but the control system in their controller is not as nice as say a KT one.
If you put the controller and battery in a frame bag and use velcro straps for the motor cable, you'd only need to disconnect the PAS and LCD cables when you swap, which is no big deal. I'd use a 260 rpm Q100H or a 201 rpm Q100H at 48v. That will give an assisted speed of about 22 mph. At 48v, you get 30% more torque. If you're sure, you want to restrict to 15.5 mph, then use a 201 rpm motor at 36v.
For a controller, at 36v, it's the S06S from BMSB, and at 48v, it's one of these, which is the same but 48v:
https://www.aliexpress.com/store/product/Free-Shipping-36V-250W-48V-350W-Controller-LCD-LCD6-display-PAS-Set-for-E-bike-kit/738588_32834523159.html?spm=2114.12010612.0.0.7e293d38ddcB77
The new tiny Xiongda motor is much lighter, and it still gives pretty good power and is very cheap, but the control system in their controller is not as nice as say a KT one.
Thanks for the quick reply. I like the sound of small and light. Is the Xiongda available with 48v? Where can I get one? What is the downside with the controller? What about the Q128 (I think) mentioned in another thread? Can I give the motor to any wheel builder and get them to make the wheel up?
If the motor is light and drag free I might not need to worry about removing the wheel, just all the other components. If this was the case, could I give the bike wheel from the bike and the motor to a wheel builder and just ask them to fit it (with shorter spokes presumably)?
If the motor is light and drag free I might not need to worry about removing the wheel, just all the other components. If this was the case, could I give the bike wheel from the bike and the motor to a wheel builder and just ask them to fit it (with shorter spokes presumably)?
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Deleted member 4366
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The Q100 is more or less drag-free. The Xiongda has a little bit of drag, but you don't notice it when riding. It comes in 48v and 36v versions.
You get the Xiongda from bonnie@xiongdsmotor.com.cn
The motor is the YTW06. You have to ask for the Li Shui sinewave controller, Bigstone LCD and a PAS. It's about $180 for all that including shipping, then about £15 duty. You have to build your own wheel. The motor looks like this - if you can see it:
You get the Xiongda from bonnie@xiongdsmotor.com.cn
The motor is the YTW06. You have to ask for the Li Shui sinewave controller, Bigstone LCD and a PAS. It's about $180 for all that including shipping, then about £15 duty. You have to build your own wheel. The motor looks like this - if you can see it:
D
Deleted member 4366
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Yes, but a PAS is much more convenient than a throttle, and a throttle isn't easy to fit to drop bars.
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Deleted member 4366
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Deleted member 4366
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That's a good question because it has a difficult answer. Generally, I'd recommend 20A max at 36v and 15A at 48v, but it depends a lot on which speed version you have, wheel size, weight, hills, etc.
I've been assuming for a while that if I convert a bike it'll be with a Q128. But having a fairly heavy motor in a bike with rear sus I'm very conscious of the weight so wondering if the Q100 would be a nice power for weight compromise. But how do you compare the torque of motors with different reduction ratios?
Lets say you have a SWX02 and a Q100 with the same amperage and voltage. I suppose the latter would have more torque due to it's reduction ratio, but can you put a percentage on how much more? Assume everything else is the same for the sake of simplicity...
Lets say you have a SWX02 and a Q100 with the same amperage and voltage. I suppose the latter would have more torque due to it's reduction ratio, but can you put a percentage on how much more? Assume everything else is the same for the sake of simplicity...
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Deleted member 4366
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My bike has air suspension and a Q128C. The suspension works very well for absorbing road bumps, but I can imagine that it would struggle to keep up on a serious off-road down-hill run. It's always the case that the lighter your wheel, the better the suspension works. That's more on rebound than compresion. You therefore have to make a judgement between how much mass you can tolerate against how much power you can have. Both the Q100 and Q128 can handle/give good power considering their mass.
Torque is directly proportional to current. Also, increasing voltage increases torque, but you have to be mindful of how it effects efficiency. A slow Q100 can go to 20A at 36v. A Q128 can manage at least 25A and I would estimate an SWX02 at around 22A.
Torque is directly proportional to current. Also, increasing voltage increases torque, but you have to be mindful of how it effects efficiency. A slow Q100 can go to 20A at 36v. A Q128 can manage at least 25A and I would estimate an SWX02 at around 22A.
I thought the Q100 had a greater reduction ratio than typical motors—like the SWX02—and I thought that increased torque...
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