Custom Stretch Cruiser Build - BBS02, 52V

[jfoster]

Hello, I'm new to the eBike world and am planning my first build. This bike is based on something I saw out at Burning Man this year.

I'm building this bike to learn bicycle building skills and to have something cool for bike parties and to cruise around the city. I do hope to take it out to the burn next year. If it is as great as I think it will be, I'll probably follow up and build a commuter eBike as well.

For the frame I'm planning to use this 26" stretch piece shown at the bottom of this post.

Here is a link to a spreadsheet of the components list.

I'm planning to use a springer fork, with a disc brake bracket to put a hydraulic disc brake on the front. I'm hoping to have a local shop weld disc brake tabs on the back of the frame. I'm planning for the bike to be a single gear, although if the frame ends up accommodating an internal hub, I'd consider replacing the back wheel.

I chose the Bafang BBS02 as the middrive, after being so impressed with the performance of the bike I am basing this on. It did not hurt to find out in my own research that the BBS02 is held in high regard. I'm planning a 52V 13.5ah Shark Pack for the battery, both items I'm planning to purchase from Luna.

Some of the parts I picked in my list are kind of cheap, I am trying to keep the price down somewhat. But I don't want to pick something that is likely to fail. This is not for single track or hard riding, but I do want it to be reasonably reliable and safe enough to let my friends try it.

I have some tools, but have not gotten this deep into bike maintenance and am hoping to start my collection with this project. This includes my first bicycle repair stand.

I have some bicycle maintenance skills. I can install a new crank by properly breaking and add links to a chain without popping out that important pin. I can back out the wheel to get proper tension. I can pull apart and overhaul a bottom bracket on a cruiser in the dark. I've also replaced a stem on a cruiser before.

However, I have not actually built a bike from the ground up before, so this is a reach project without adding the eBike part. I am pretty good at figuring things out though and don't mind asking for help when I have tried things.

That said, I would appreciate feedback from this group on my plan and any suggestions or heads-up on gotchas.

I think I have all the bicycle components figured out, and I've watched BBS02 install videos. But that whole portion is most foreign to me.

Again, here is a link to a spreadsheet of the components I'm planning.

Here is my current budget for the bike:

Total Regular Parts $649.44
Total Electrical Parts $962.95
Total Tools $248.69

All things $1,861.08

 

[amberwolf]

If you need any bike-maintenance / etc info to help with the build, my first stop is always http://sheldonbrown.com (which itself has links to some other good places).

 

[jfoster]

Hey, thanks for that. I’ve used the late, great Sheldon Brown's site as a reference before. My normal burning bike is a 1938 Colson step through. His site has a lot of old bike info useful for that.

 

[jfoster]

I got my frame and it has a standard american 2" bottom bracket. Here is a photo of the bottom bracket area.

My understanding is the challenge with the BBS02 is that when you convert the 2" BB using an adapter like this, is that the centering doesn't allow for a lot of room for the motor to be fit.

I found this thread discussing this issue, but doesn't seem to resolve if the bbs02 would fit in a 2" american bb with a centered american conversion to English BB.

I found another thread where people are using an "eccentric bottom bracket conversion" custom fabricated part to accomplish something similar to what i'm after.

From what I have read the BBSHD has spacing that allows for that centered version above. That said, I think the 02 is well enough for this first build and would prefer to stick with that drive.

If anyone has feedback or experience with this situation, I'd appreciate hearing it!

 

[Rassy]

This is a BBS02 gotcha that I recently encountered on my newest BBS02 purchased from Luna. I was not aware that Bafang had made a major change to their software when they added a dedicated gear sensor to the BBS02, nor was I aware that the BBS02 I purchased was equipped with a dedicated gear sensor. I'm not sure yet if all the new BBS02's are equipped with a dedicated gear sensor or not.

The issue for me is that you can now no longer pedal when using the throttle on the BBS02 unless you go to full throttle. This is true for any PAS level, 0 through 9. This is the sixth BBS02 I have purchased over the last four years and I am figuring out how to live with the change, but will probably spring for a new controller that fits when and if I can find one.

And yes, all six of them are still in good operating condition, the oldest one is resting on a shelf, two are on my trikes, and the other three are on friends/relatives trikes/bikes.

Also, imagine having to tell a guest rider that they can't use the throttle for a little extra power when pedaling up a hill because that could result in breaking a chain, the derailleur or gears, or internal Bafang gears, etc.

EDIT: I purchased and installed a new controller, manufactured 09/14/17, that does not have the Dedicated Gear Sensor/Cable, and it also has the problem with not being able to pedal with normal throttle usage. So the conclusion I have to make is that Bafang made some other change to the controllers that doesn't have anything to do with the Gear Sensor.