Will a mid drive fit this front loader cargo bike?

[pnwscooter]

Hi all,

I've been puzzling over whether I can fit a 1000w BBSHD in the upper "triangle" area (rectangle here) above the bottom bracket. This particular cargo bike design has two horizontal tubes extending forward from the bottom bracket. 68mm shell width.

Any thoughts/advice? I guess I could go with a hub motor, but I'm intrigued by the mid drive...

Thanks!

 

[Balmorhea]

You can probably fit a BBSHD in the space above the horizontal boom tube.

Also consider a BBS02, which doesn’t put your feet quite as far apart.

 

[pnwscooter]

My concern is the “probably” part. Not sure I want to gamble the $1k... It looks close, but I’m having trouble finding dims of the BBSHD motor’s diameters and their spacing from the BB center.

I guess if it doesn’t fit I can just find a cool bike to build up anyways.

 

[pwd]

Anything here help?:
https://www.google.com/search?q=bbshd+dimensions&rlz=1C1KAFB_enCA525CA525&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiHnrap46zrAhXiT98KHS3UAFwQ_AUoAXoECA4QAw&biw=1536&bih=754

 

[E-HP]

This article has some good pictures to get a better idea. Not the same frame situation, but the photos help to show where the contact points might be.
http://dukesmotoelectric.blogspot.com/2018/02/bbshd-mounted-in-triangle-on-in-barrel.html

 

[pnwscooter]

E-HP, thanks for the link. I found a similar post on an electra cruiser:
https://electricbike.com/forum/forum/builds/ebike-building-directions/7325-bbshd-on-an-electra-cruiser

I think the BBSHD works in the triangle on those cruisers since the seat tube is set back from the BB. I've mocked this up and I need to double check the scale, but I don't think there's enough room for the motor with the seat tube right above the BB. Those tabs get in the way, and then some... Maybe the rule for in-the-triangle mounting is that the seat tube needs to be set back a certain distance from the BB?

I have dug the googles for diagrams, but they're limited and require some guesstimating. i just wish they had a few more dims so I could determine if it would fit better.

 

[Bigwheel]

If you are in PDX swing by either PX Cycles in North PDX or Nomad Cycles in SE. They both have installed lots of Bafang mid drive kits and you could get hard data from either on fit and take measurements from an actual motor.

 

[E-HP]

If you can get a good photo of the motor installed on a straight tubed frame, you may be able to extrapolate the opposite angle required, sort of like this, making some assumptions relative to your frame tube diameters:

I don't think it will fit.

 

[pwd]

If you aren't able to mount the BBSHD, you can probably use a more modular mid-drive system like the Cyclone 3kw etc... when the motor to crank reduction isn't integrated like on the BBSXX ,you can mount the motor further away from the crank like this (would require some custom mounts):


This solution looks like it works well using shaft collars if you have a normal tube frame. Link to his video if you want more detail on the mounting brackets:
https://www.youtube.com/watch?v=3FVt1rPqHIg

 

[pnwscooter]

Well, I rode the bike over to Nomad Cycles and showed it to Brad. He was super helpful and figured that it wouldn't fit, without cutting out a section of the added horizontal tube and adding reinforcements, and $, etc.

So it seems like the best solution will be some kind of hub motor drive. I could chase the mid drive and spend a lot of $, or just do the hub motor for now and pick up a different mid drive compatible cargo bike in the future.

 

[Balmorhea]

So it seems like the best solution will be some kind of hub motor drive. I could chase the mid drive and spend a lot of $, or just do the hub motor for now and pick up a different mid drive compatible cargo bike in the future.

Or hang the mid drive underneath. It's not like you're going rock crawling with your long john.

 

[pnwscooter]

Or hang the mid drive underneath. It's not like you're going rock crawling with your long john.

The problem is that second horizontal tube. Even with the motor rotated back towards the tire, it's likely too tight.

 

[Nightdiver13]

You could also try a different form factor mid motor like the Revel Propulsion one. Currently sold out as far as I know, but you could contact him and see if it would fit.

 

[Bigwheel]

Well, I rode the bike over to Nomad Cycles and showed it to Brad. He was super helpful and figured that it wouldn't fit, without cutting out a section of the added horizontal tube and adding reinforcements, and $, etc.

So it seems like the best solution will be some kind of hub motor drive. I could chase the mid drive and spend a lot of $, or just do the hub motor for now and pick up a different mid drive compatible cargo bike in the future.

Personally I don't feel there is any shame in going with a hub drive for your bike. I'd take a serious look at a Grin GMac series clutchless geared hub motor. A Grin system might cost more but according to my experience with them it is a lifetime investment in quality and support, although they have been a bit behind due to Covid they seem to be getting on track here by 9/1.