Mid drive concentric bottom bracket

Sguzman1o

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Oct 20, 2021
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I’ve got a cyc x1 pro gen 2, and looking to buy a full suspension bike capable of single speed without all the added extras needed with bikes that have vertical dropouts. My plan is to run it at 1500/2000watts a nuvinci Igh. I’ve seen a Kona bass and thought all was good but just realized the suspension main pivot is connected to the bottom bracket, would I still be able to fit the motor as normal? Also are there any other full suspension bikes that you know of that will work? Thanks people
 
Anyone?

From the web:

IMG_1123.PNG

No doubt viewing a bike frame for such advise would be better done hands on than a photo "worth a thousand words" because after a hands on look the answer could be economized to one word -- 'yes' or "no".

The first poster has ask, "...would I still be able to fit the motor as normal?" From the photo I see the likes of threads inside the BB shell. Are they 1.375" x 24 TPI? What I cannot ascertain from the photo is whether the BB shell extends laterally beyond the parts of the suspension rings that rotate near the ends of the BB shell. If the BB shell ends extends beyond the suspension frame rings that surround the BB shell ends, then the motor frame plates would easily be pressed against those shell ends and the motor mount would be "normal". If not a normal mount, I suspect some form of standoffs will get the mount satisfactory.

I do like the suspension rotating around the BB shell because upon compression of the rear suspension the chain neither tightens nor loosens and rear drops function as chain tighteners.
 
A screen-copy of that bike's BB shell:

IMG_1124.PNG

From this BB region photo it looks like the fixed BB shell does extend laterally beyond the bearing's blue seal ring. But without knowing the BB's ID, I cannot say whether or how to go about mounting, except if the size is 1.375" x 24TPI, the Cyclone motor plates would touch the shell rim and bind when the bearing cups were tightened. Hence, a normal mount.
 
On a second look it looks like the inner bearing rim extends beyond the BB shell so I must retract the premise of a normal mount until taking the BB region apart and looking for internal (hidden) bearing stops (shoulders).
 
I think you would be fine using a common BB mid-drive on this setup. The BB shell does appear to extend beyond the bearings. If it did not then It would possibly bind with any external bearing bottom bracket which is most of them these days.

As for other bikes using this concentric pivot design:
  • DMR Bolt Long
    Has bolt on vertical drop outs but you could make your own so they are horizontal for easy tension
https://www.vitalmtb.com/product/guide/Frames,7/DMR/Bolt-Long,25641

  • NS Soda Slope
    Has horizontal drop outs for chain tension
https://nsbikes.com/soda-slope,125,pl.html

  • F.U.T.R. Beta ebike frame
    Has integrated battery box that may get in the way of the mid-Drive unit
http://www.futrelectricbike.com/product/beta-snow-white/

Both the Soda Slope and the DMR Bolt are going to be more dirt jump/slope style bikes. Smaller frames with less emphasis on handling and braking. I think that means super fun but someone looking for a high speed Long travel machine similar to a Down Hill bike might not want to use one of these.

In my mind the sacrifice of a Dirt Jump style bike is pedaling efficiency. Once you have the motor that goes out the window so I think it would be great. Slam the seat all the way down since you aren't pedaling and use the motor to get from one riding zone to the next. But I understand not everyone has the same goals in mind. My ebike goals are almost exclusively late night Urban Hooligan stuff.
 
It's a good enough frame (Kona Bass) for CYC X1, I think. It fits for Dolphin or Polly 65 cells battery case.
But for Bafang BBS or TSDZ2 this frame is not suitable. So I had to install hub motor.
10nxstv.jpeg
controller6.jpg
 
Hi, thanks for the replies. All the replies are slightly mixed and I don’t want to spend the money on the bike if it won’t fit. My main worry is if I fit the motor to the bike the way the suspension pivot is connected to the bottom bracket it would cause the motor to move..?
 
ashot said:
It's a good enough frame (Kona Bass) for CYC X1, I think. It fits for Dolphin or Polly 65 cells battery case.
But for Bafang BBS or TSDZ2 this frame is not suitable. So I had to install hub motor.
10nxstv.jpeg
controller6.jpg


Why was it not suitable for the bbshd or tdz2? Wouldnt that also make it unsuitable for the cyc?
 
Sguzman1o said:
Why was it not suitable for the bbshd or tdz2? Wouldnt that also make it unsuitable for the cyc?
Sorry for necro post, I had not read this forum for a long-long time. :oops:
And what about your question. - Please look at this picture below. The frame has a massive part around bottom bracket. And this do not let to mount TSDZ2 and Bafang BBS motors.
kona bass.JPG.
 
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