Alfine 11 Hub gear?

Sedentix

Finding my (electric) wheels
Apr 18, 2022
12
4
Any thoughts on putting a Bafang mid drive motor on a bike that has Shimano Alfine 11 Speed Hub Gear?
Should I be worried about the input power, it's a 250Watt. It's possibly going on a Genesis Fortitude Adventure.
Ideas, warnings and Large sums of money appreciated.
Ta Muchly.
 

peter.c

Esteemed Pedelecer
Apr 24, 2018
1,611
491
thurrock essex
The alfine 11 would not be my first choice can prove fragile .Have used alfine 8 and nexus 8 with success. But depends on the bb style if eccentric type this can cause a problem, and always fitted a alfine chain tensioner. The picture i found of the 2013 version it looks perfect as has horizontal rear dropouts and smooth bb
 
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Sedentix

Finding my (electric) wheels
Apr 18, 2022
12
4
Thank Peter. I was thinking that, with it's need for fine tuning, the 11 Might be a bit too far. I'll scratch that thought.
 

Bonzo Banana

Esteemed Pedelecer
Sep 29, 2019
733
428
I don't think its related to the wattage its always about the torque the motor can generate. You get mid-drive motors that range from about 40Nm output which are typically used with hub gears to other motors that are close to 100Nm and typically used for e-mountain bikes and would not be ideal for hub gears except perhaps for the very strong and basic 3 speed hub gears, Sturmey Archer, Nexus 3 etc. Those can take a lot of abuse.

Ideally if you have more complicated hub gears a front hub motor is the best combination as it takes a huge amount of the workload off the hub gears so can massively extend the life of hub gears and these can actually be more powerful than the very low power 40Nm mid-drive motors that are used with hub gears plus you can choose lower gearing more safely for when the motor isn't assisting. You also get all the benefits of hugely extended drivetrain life and much reduced instances of chains snapping.

Some of the pre-configured ebikes with Bosch mid-drive motors of 40Nm and with lets say Nexus 8 or Nexus 7 don't have great low gearing, perhaps a 46T chainring at the front and a smaller cog on the rear so they are protecting the hub gears by avoiding very low gearing.

I personally think a front hub motor is the best combination to go with hub gears most of the time but it really depends how you use the bike. If you are clocking up 1000s of miles commuting then I think a hub motor is the best option but for more casual occasional riding then I guess a mid-drive is a good option.
 
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Sedentix

Finding my (electric) wheels
Apr 18, 2022
12
4
Thanks, you've articulated what I was thinking. I'm in no hurry to do that bike, funds being tight as they are, so I'll follow your advice. I do have an, older, Nexus 7 wheel, might think of putting something together using that. My main idea with the mid drive is to put in on my Trice recumbent. Just thought I'd get ideas on my other options.