Hub motor with internal gears?

[sjuft]

I'm looking to convert a cargo bike (Babboe Curve).
I already own a few bikes with tsdz2 mid-motors and would like to do the same to the curve. But due to the design around the bottom bracket, this wont be possible.

The bike comes with a Shimano 7 speed rear hub, and therefore no eyelet for a derailleur. So not sure if external gears with derailleur is possible.

Is there any good hub motors with internal gear's? Or other options i could look into?

 

[Chalo]

Is there any good hub motors with internal gear's?

Grin sells the TDCM hub motor with 5 speed internal gears. Other than ancient SRAM Sparc internally geared hub motors, that's the only one I'm aware of.

https://ebikes.ca/shop/electric-bicycle-kits/tdcm-igh.html

You could fit dual Grin All-Axle hub motors to the front wheels, but that would be a bigger project.

 

[999zip999]

I like that bike. I think Chalo nail it. Just have to get it laced. You must map out how everything fits before you try to make things fit. As some frames wouldn't let a rear hub because a rear derailleur that has no room for a nut ect.

 

[LewTwo]

Grin sells the TDCM hub motor with 5 speed internal gears.

Except it has been listed as "Out of Stock" for over a year.

 

[amberwolf]

Assuming the TDCM hub is no longer available new (I haven't checked), then if you have either the skills and tools or the money for someone that does, you could modify many DD hubmotors to accept an IGH in place of their original axle and stator support. It's a significant modification and would require machining a number of new parts to fit them together, but it's possible, and is basically what the TDCM IGH DD hubmotor is (an "Ultramotor" with an IGH installed in it's core).

Some time ago I considered doing exactly this with an old 9C DD hubmotor and a Sturmy Archer 3speed, but I didn't have the knowledge or ability to do it myself, or money to pay anyone to, so it's just a list of considerations for doing such a conversion:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=75874

 

[amberwolf]

Regarding other options, is this the trike you have?
https://www.babboe.co.uk/babboe-curve



If so, then depending on your assist needs, you might consider a motor mounted above the rear wheel behind the seat that drives the *left* side of the wheel, with a sprocket mounted to the disc rotor attachment point. If there is space you can do it alongside the rotor, otherwise you'd be replacing it (since you have front discs on both sides, that shouldn't impede your braking ability significantly).

If you want the motor to run thru the gears, you can place it instead somewhere near the cranks and have it drive the left side of the cranks, stokemonkey-style, using a narrow motor (like a hubmotor not in a wheel). The catch with this configuration is it is throttle-only; if you used PAS it would be driven by the motor and thus can only go faster or have more power applied than whatever level it would be running at at that moment, unless you first disengage the motor power so it stops driving the pedals and thus the PAS. (there are possible systems that would detect *only* the torque between pedal and crankshaft, across the crank itself, but they aren't standard ebike control systems and would have to be designed for your trike or adapted to it).


Optionally, since your front wheels are double-ended axles, you could replace one or both with small hubmotors. If they are unusually-narrow dropouts, folding-bike hubmotors may fit.

Note that even if you only use one front hubmotor, while it will torque-steer, it's easily possible to get used to this and control the trike perfectly fine, though it will take some practice under various conditions.

 

[Chalo]

If your dropouts open to the front, you can use a common derailleur hanger claw.

If your dropouts open to the rear, you can use a derailleur hanger designed for track ends, though this will require a bit of metalworking to fit a hub motor axle.

 

[amberwolf]

There are also these threads about the Babboe Curve (and it's E version) that may give you some ideas, but unfortunately none of them actually went to the conversion stage:

https://endless-sphere.com/forums/viewtopic.php?f=3&t=101075
https://endless-sphere.com/forums/viewtopic.php?f=3&t=116356
https://endless-sphere.com/forums/viewtopic.php?f=2&t=111060

There are others that may have useful info if you search on Babboe or bakfiets or even just cargo trike, though they may not directly apply to your specific trike design.


This one has a post stating that some people have modified the frame a bit to successfully use the TSDZ2 middrive
https://endless-sphere.com/forums/viewtopic.php?f=28&t=95693&p=1478035&hilit=babboe#p1478035

This post showed a complete conversion but the converted image is missing, so you'd have to contact the poster (yapi) to find out what they did, since they never bothered to post about any of it.
https://endless-sphere.com/forums/viewtopic.php?f=6&t=235&p=1012985&hilit=babboe#p1012985
it might be one of the ones here in their flickr stream though
https://www.flickr.com/groups/ebikes/pool/v-fiets

 

[sjuft]

Thanks for all the answers.

I think i have to make a mid motor work. Especially as i have tsdz2 on 2 other bikes and i would like that theyre all the same.
Upon inspecting the babboe curve, i think it may be possible with som modifying,

Under the frame tube, theres a flat piece of 3mm metal, i guess for extra support. This goes all the way from the front end to the bottom bracket. (Image attached)
It's only supporting in a few spots where it is actually welded to the rest of the frame. Everywhere else theres actually a 1-2mm gap.
So i guess it would be easy to remove just 2 inches right underneath the bottombracket, which would make enough room for a motor.
But im not sure if this would ruin the strength of the frame.
And in that case, if it would be possible to add a new weld 3 inches in front of the bottom bracket.

 

[nicobie]

Obviously I'm missing something. Why not just use a rear hub motor? The motor has plenty of power. It won't need gears to get it up a hill.

 

[sjuft]

Obviously I'm missing something. Why not just use a rear hub motor? The motor has plenty of power. It won't need gears to get it up a hill.

- Requires a whole new wheel.
- Only external gear (bike is for my sister, so low maintenance is preferred = internal gears)
- There's no derailleur hanger on the frame.
- I already own 2 tsdz2 systems. Huge advantage running same system and batteries on all my bikes.