casanewt

Alright fellow C&V fans, who out there has gone to the dark side and done an e-bike conversion on an older bike and how would you rate the results? I am getting ready to install a Bafang BBS02B mid-drive unit on to my unappreciated 1988 Shogun Alpine GT. It just does not get ridden as much as my Treks, Fuji, and Miyata touring bikes and seemed like the right one to experiment a bit with.

Classtime 

https://www.bikeforums.net/electric-bikes/

veganbikes

There are plenty of quality e-bikes on the market I wouldn't covert an old bike that isn't designed for the loads of an e-bike.

cudak888 

Mid-drive? Should be interesting. Sticking with the derailer system, single ratio, or IGH to complement it?

Also, I'm not one to cry "e-bike stresses!" without knowing the specs of the motor. Sure, if the dropouts look like they've been brazed cold, I'd avoid such a conversion - but otherwise, I'd expect unwanted cold setting long before catastrophic failure.

I would consider a Surly tensioner on each side of the dropouts to keep the rear wheel from shifting under the torque though. They make a few versions that are adaptable to horizontal drops.

-Kurt

casanewt

Sticking with the derailleur drivetrain. Plan to be very mindful of using the motor smoothly and setting it up and riding it to put more normal stress levels on the bike. This is definitely an experiment to see how this works out. It is a 750W/48V drive.

cudak888 

There are enough BBS02B's installed on completely stock Shimano cassettes not designed for e-bikes out there. At most, you might wear out the small ring prematurely or wind up with chain skate, and if there's any damage, it'll probably bend the frame around the bottom bracket - that Bafang motor is basically acting on the frame and the drivetrain as would an immensely strong rider.

Convert that rear axle to nutted and install those Surly axle tensioners.

-Kurt

casanewt

Great info Kurt. Thanks.

casanewt

Changed my mind and decided to convert a different bike. I knew my old motorcycle buddy Michal was a serious mountain biker, but I did not know until a few years ago that he was also a big e-bike builder. Mike had a used Bafang BBS02B 750W he was selling and I jumped on it. He came over today and we built up this 1985 Panasonic ATB. I absolutely love the conversion. I wanted an urban assault bike that could also do gravel rides. I think I will throw some more gravel appropriate tires on it soon, but for now it rules the tarmac.

Wildwood 

That was quick.
Looks like a better platform.


Love a follow-up report after a hundred miles or more of familiarity. 750watts is pretty big, right?

cudak888 

Not only does that look clean, but it looks good too.

Any plans for a tensioner or chainrings on the front chainring to prevent the chain from dropping? Perhaps one of those clutched modern RDs? I know that front Bafang ring weighs almost as much as a boat anchor and has pretty beefy teeth, but I tend to fear 1x systems that don't have something to keep that chain from popping off.

-Kurt

casanewt

This is the better platform for what I wanted to do. If you look at the Bafang mid-drive kits, you will see how simple the install is. Remove the crank and the bottom bracket. Drive unit fits right through the bottom bracket. Mount the battery to the water bottle mounts & run the controls. Simple and completely reversible. The torque is fantastic from the 750W version. range should be around 30 miles using the lower assist modes, which are still plenty powerful. Not sure what my top speed is yet, but it depends on your gearing. It could probably hit close to 30 miles an hour, but real world, zipping around at 15-20MPH is plenty fast. The battery I have is the 48V 13.5 Ah.

Soody

thats awesome

casanewt

Yep, a simple tensioner or chain guide is going to be needed because the older rear derailleur has a tired main spring. Honestly, the 10 mile shakedown ride was glorious, but I did have to hop one major curb and the chain hopped off the front chain ring on the landing. No real issue because I knew it was coming, was not pedaling, and had my weight off the crank as I was hopping it.

cudak888 

It just dawned on me that the Bafang's design prevents the installation of a tensioner to the drive side of the BB.

This thread is interesting - might be just what the doctor ordered: https://www.bikeforums.net/classic-v...erailleur.html

-Kurt

casanewt

Lots of potential options:

https://www.amazon.com/Origin8-Torql...08ZTLV9W&psc=1

https://www.amazon.com/B-Labs-C-Guid...89026616&psc=1

https://www.ebay.com/itm/27383340289...kaAmixEALw_wcB

cudak888 

Not a fan of things that have to be zip-tied to the chainstay. Partial to the first one, as I believe there's less chance of the chain jumping off the entire ring if the top - where the takeup happens - is protected first.

It's also the only one that doesn't look like a kludge.

-Kurt

casanewt

I ordered a couple of different options to try out. Some recommend leaving the front derailleur on to act as a chain guide. I took it off during the install mainly because I did not want something on there that could accidentally drop the chain if the shifter was bumped and I wanted the display by my left thumb for operation.

Bianchigirll 

jeirvine 

How does it attach? Does the BB threading matter? Could you pop one into a Swiss-threaded frame?

cudak888 

Don't quote me on this, but I believe it's not threaded on the drive side - just slides in - and the opposite side is English.

An adapter might do the job though...

-Kurt

browngw 

This type of conversion has been on my mind lately. Just over a year ago, my wife and I bought a 2019 Giant Lafree ebike and have enjoyed them immensely. She has had some health problems but still continues to ride with the ebike. One of the great things about the Giant/Yamaha mid drive system is the torque (60Nm) and the seamless torque and 5 other sensor controller which other than a smooth transition of power makes it feel like riding a real bike. Now well into our seventies, it is time to start looking at other conversions. I am considering a 1995 Norco and my 2014 Salsa Vaya that I own. The Giant setup is 500W and 36V and provides lots of assistance up to 100km (real world tested!) How these motors are controlled is causing me the biggest issue. How is your Bafang unit controlled?


1995 Norco Katmandu

Fahrenheit531 

Death first.

casanewt

These Bafang units are cadence sensing. Bafang has more expensive torque sensing units as well. Torque sensing is what Bosch, Yamaha, and other more expensive units have. Tongsheng is another option with torque sensing that is a bit more value-priced. https://edrivenet.com/tongsheng-tsdz2-vs-bafang-bbs02/

casanewt

BB treading does not matter on the BBSXX series. It does not use them.

cudak888 

So that left ring doesn't thread into the BB, but threads onto itself and sandwiches the drive system between the shell ends?

-Kurt