Yuba, meet Rohloff, and this is Bafang

Trevtassie
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Re: Yuba, meet Rohloff, and this is Bafang

Postby Trevtassie » Thu May 04, 2017 9:36 am

icicic wrote:
Trevtassie wrote:Ah, bugger it, just realised the wheel I bought is laced wrong, leading spokes are head out...dang... oh well, re-lace it tomorrow.


Well that sucks a little. I've been meaning to check mine - since I bought it. Given that it's only a 32 hole, and I'm carrying some weight, I think I'd better get around to it.

I'm gonna fit the reinforcing rings while I'm at it...

Calvin27
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Re: Yuba, meet Rohloff, and this is Bafang

Postby Calvin27 » Thu May 04, 2017 9:36 am

My 2c on the bafang is to go for the torque sensing mid drive instead. Reasons why:

- Less wiring and other stuff. No cadence sensor, no throttle controller.
- If range is important, a torque sensing is much more efficient (30% measured in a bro-science standard test)
- I haven't had experience with rohloffs but I have used shimano hub gears and they hate shifting under load. The torque sensing mid drive is very progressive and shuts off once you stop applying load. Th bafang simply goes if you are spinning. The problem being sometimes it means you shift under load when you don't think there is a load.
- Weight. The bafangs weight about 40% more then the torque sensing mid drives. they are built for up to 750w and nerfed at the controller.

Good luck and let us know how you go. After building a few with my mate, I'm pulling the trigger on my build as well.
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icicic
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Re: Yuba, meet Rohloff, and this is Bafang

Postby icicic » Thu May 04, 2017 11:28 am

Calvin27 wrote:My 2c on the bafang is to go for the torque sensing mid drive instead. Reasons why:

- Less wiring and other stuff. No cadence sensor, no throttle controller.
- If range is important, a torque sensing is much more efficient (30% measured in a bro-science standard test)
- I haven't had experience with rohloffs but I have used shimano hub gears and they hate shifting under load. The torque sensing mid drive is very progressive and shuts off once you stop applying load. Th bafang simply goes if you are spinning. The problem being sometimes it means you shift under load when you don't think there is a load.
- Weight. The bafangs weight about 40% more then the torque sensing mid drives. they are built for up to 750w and nerfed at the controller.

Good luck and let us know how you go. After building a few with my mate, I'm pulling the trigger on my build as well.


Thanks for that Calvin

I do like the idea of the Bosch torque sensing mid drives and I'd like to test drive one before my next build which I hope to get onto in a couple of months. I'm in Sydney, Australia. Do you know where they can be tested?

The amount of wiring doesn't concern me either way, and the weight difference isn't particularly important to me given the combined weight of my bike, rider and load, (but it is something, I suppose).

But what is important to me is the wear and tear on my expensive gears and the reduction of maintenance or potential damage there, though I'm not sure of the level of risk with my Bafang,

Second most is potential increase of range which would add up to savings on battery replacement: 30% is a big claim though, so I'd like to see evidence of efficiencies before I got too carried away by that.

Meanwhile, I've already put my Yuba and Rohloff and Bafang mid-drive PAS system together (a few weeks back) and I'm quite happy with it's range, speed, and ability to carry my current load up some pretty good little hills. I keep it in geared lower to ensure that the motor is spinning fast and less strained, and I find that is easy to do.

The Rohloff doesn't like to shift under load. Do any gears like to, apart from the Nuvinci 360? But it's not a problem so far. A monetary pedal stop or tap of the brakes cuts the power and apparently the gear sensors do the same, much more efficiently: mine isn't yet attached).

Calvin27
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Re: Yuba, meet Rohloff, and this is Bafang

Postby Calvin27 » Thu May 04, 2017 12:28 pm

icicic wrote:
I do like the idea of the Bosch torque sensing mid drives and I'd like to test drive one before my next build which I hope to get onto in a couple of months. I'm in Sydney, Australia. Do you know where they can be tested?

The Rohloff doesn't like to shift under load. Do any gears like to, apart from the Nuvinci 360? But it's not a problem so far. A monetary pedal stop or tap of the brakes cuts the power and apparently the gear sensors do the same, much more efficiently: mine isn't yet attached).


The bosch is another price level up from the bafang. I was referring to the chinese torque sensing mid drives - about the same price as the bafang.

http://ebike-sales.co.uk/product/tongsh ... ersion-kit

As for the nuvici, my mate has tongshen torque sensing mid drive and a nuvici hub and shifting is not great. I'd imagine it would be worse with a bafang.

they are quite different systems. The bafang you get a real sensation of the motor kicking in. The torque sensing you wouldn't even know it was there. The power is quite proportional and you just feel like a more powerful rider. The ride between the two systems is quite different - definately recommend giving them a shot. After riding both, my mate and myself prefers the torque, the other is going for the bafang and the last guy has 2 bafangs and on torque (he was the beta tester haha).
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icicic
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Re: Yuba, meet Rohloff, and this is Bafang

Postby icicic » Thu May 04, 2017 12:56 pm

Calvin27 wrote:The bosch is another price level up from the bafang. I was referring to the chinese torque sensing mid drives - about the same price as the bafang.

http://ebike-sales.co.uk/product/tongsh ... ersion-kit

As for the nuvici, my mate has tongshen torque sensing mid drive and a nuvici hub and shifting is not great. I'd imagine it would be worse with a bafang.

they are quite different systems. The bafang you get a real sensation of the motor kicking in. The torque sensing you wouldn't even know it was there. The power is quite proportional and you just feel like a more powerful rider. The ride between the two systems is quite different - definately recommend giving them a shot. After riding both, my mate and myself prefers the torque, the other is going for the bafang and the last guy has 2 bafangs and on torque (he was the beta tester haha).


Sounds good. It doesn't have the name recognition of the Bafang, which is always unnerving but I'll have to look at it when I have time. Thanks again.

mlavis
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Re: Yuba, meet Rohloff, and this is Bafang

Postby mlavis » Fri May 12, 2017 1:47 pm

@calvin27- I've been interested in the Bafang for a while now and had never seen the Tongsheng alternative. It looks pretty neat! Does the fact that it is a torque sensing motor mean you do not need the brake/motor shut offs? Ie as soon as you stop pedaling the motor stops running?

I have one design issue that I wonder if you could answer for me. I'm interested in using this on a bakefits style cargo bike. My bike has the cargo boom welded to the bottom bracket, the bottom of which runs parallel to the ground and attaches at the same level as the bottom of the BB shell. It looks as though the motor requires a little space in front of the BB and above the level of it's lowest point (requiring a sloping down tube) to mount. Is that the case? Or do you imagine I might be able to get it to fit with my bike's configuration. There are some pics in this thread that better illustrate what i'm talking about.

viewtopic.php?t=92939

Mark

Calvin27
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Re: Yuba, meet Rohloff, and this is Bafang

Postby Calvin27 » Fri May 12, 2017 2:20 pm

mlavis wrote:@calvin27- I've been interested in the Bafang for a while now and had never seen the Tongsheng alternative. It looks pretty neat! Does the fact that it is a torque sensing motor mean you do not need the brake/motor shut offs? Ie as soon as you stop pedaling the motor stops running?

I have one design issue that I wonder if you could answer for me. I'm interested in using this on a bakefits style cargo bike. My bike has the cargo boom welded to the bottom bracket, the bottom of which runs parallel to the ground and attaches at the same level as the bottom of the BB shell. It looks as though the motor requires a little space in front of the BB and above the level of it's lowest point (requiring a sloping down tube) to mount. Is that the case? Or do you imagine I might be able to get it to fit with my bike's configuration. There are some pics in this thread that better illustrate what i'm talking about.

viewtopic.php?t=92939

Mark


I haven't done my very own install yet (mine is still in the mail). I went torque sensing mainly for the slightly better power usage (requires your own input, but mostly because there is no brake cutoff since I'm running hydraulics. I have no idea if the motor stops automatically or not riding it, but there is definately none of that powering on after you stop pedalling you get from a bafang.

Strangely one of my mates has the tongshen on a bakefits! I haven't taken a look at his bike closely but I do recall there were some issues with the BB area since it's a bit atypical. The motor is rotated back a little and that has issues with some of the mounting hardware (had to grind a bit off) and a little play in the motor. I haven't seen the bike since the first install but he has mentioned he's done some stuff to stiffen it up and prevent movement. I can ask and see what he says, maybe pics too.

Having said that though. It looks like the standards 250W torque sensing is not quite enough for the bakefits. Mate rekons a throttle is a much better option, especially to get the heavy bike+ load moving.
Last edited by Calvin27 on Fri May 12, 2017 4:21 pm, edited 1 time in total.
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icicic
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Re: Yuba, meet Rohloff, and this is Bafang

Postby icicic » Fri May 12, 2017 3:32 pm

mlavis wrote:My bike has the cargo boom welded to the bottom bracket, the bottom of which runs parallel to the ground and attaches at the same level as the bottom of the BB shell.


I don't know about the Tongsheng but yeah, I don't think the Bafang will do it for you if you've got the boom bellow the BB. You might like to look at variations where people have mounted a hub motor to their Downtube and used those as Mid motors.

mlavis
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Re: Yuba, meet Rohloff, and this is Bafang

Postby mlavis » Fri May 12, 2017 4:35 pm

(AT) Calvin27- Interesting to hear about your mate and his bakefits. Would be great to see some photos if you can track any down. Alternatively, even if you just know the model of the bike he is using I could get an idea as to compatibility with different frame designs.

Cheers,

Mark

Calvin27
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Re: Yuba, meet Rohloff, and this is Bafang

Postby Calvin27 » Fri May 12, 2017 6:29 pm

mlavis wrote:(AT) Calvin27- Interesting to hear about your mate and his bakefits. Would be great to see some photos if you can track any down. Alternatively, even if you just know the model of the bike he is using I could get an idea as to compatibility with different frame designs.

Cheers,

Mark


Yep I'll chase up and let you know. This is the model he has though http://dutchcargobike.com.au/shop/bakfi ... argo-bike/
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