# Electric motor retrofit



## Mesozoic (Apr 20, 2004)

Bicycle enthusiast from an early age and fortunate to have a small collection - even more fortunate to live near a greenway that easily takes me from my home to my office downtown (about 15 miles) without having to share a path with cars/trucks/motorcycles. I'm interested in taking one of my lesser used bicycles and retrofitting it with an electric motor for assist or even all out full power motorization. Since my office does not have showers and I live in one of the hottest climates in the US, I'm interested in this because I cannot afford to be sweaty all day at the shop. 

Does anyone have any recommendations or suggestions on the best kits and resources available to begin a retrofit project? I'm also an avid sport bike enthusiast, but again, I'm sharing the road with cars and trucks. The greenway with its dedicated path next to the "river" is extremely appealing as COVID retreats.


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## Old & Slow (May 3, 2020)

Do a search on Bafang both here and Google for mid-drive conversions. As to hub drive many of those too. Sounds like you are doing pavement, therefore modest grades. I had an Lectric XP hub drive which has a a big fan base, but I would strongly suggest modest grades only. Its biggest appeal is $800 to your door which beats most conversions. Again Google is your friend.


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## EKram (Oct 30, 2020)

I have had same thoughts on retrofit. See what the eBike stuff is all about.
My hesitation is wondering if the frame can stand up to the different stress on it? I think initially the frame will be fine but before I expend time and money I don't want to create a "Frankenstein" bike.


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## fos'l (May 27, 2009)

I have an offroad Bafang BBS02-equipped bike and an errand bike with a 48V, 1000w rear hub motor (operated at 52V, 33+ mph). Both are six years old and show no signs of wear in either the motor systems, or bikes. If your commute doesn't involve steep hills, a rear motor should serve you well (look at the tutorials at ebikesca). If hilly, a mid-drive is best IMO.


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## Mesozoic (Apr 20, 2004)

fos'l said:


> I have an offroad Bafang BBS02-equipped bike and an errand bike with a 48V, 1000w rear hub motor (operated at 52V, 33+ mph). Both are six years old and show no signs of wear in either the motor systems, or bikes. If your commute doesn't involve steep hills, a rear motor should serve you well (look at the tutorials at ebikesca). If hilly, a mid-drive is best IMO.


No major hills on the commuter bike path here. This is the 1st time I've heard that the mid-drive would be better for large elevation gain, but I appreciate that. The rear hub motor system seems to be the least invasive route. Seriously, I'm thinking of slapping on some paniers and going for it. I feel like an asshole when I ride my motorcycle and bypass 50 cars in a jam via the bike lane. It's time to just commit to the retrofit e-bike and be done with it.


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## RickBullottaPA (Mar 4, 2015)

For a commuter bike, I'd consider it, but for an eMTB, no way. I'd want a purpose-built design with the drive system integrated into the frame properly.


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## calimander (Feb 25, 2020)

Luna ebikes has a lot ideas you could use


Sent from my iPhone using Tapatalk


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## sgltrak (Feb 19, 2005)

What about one of those electric push trailers? 








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## Mesozoic (Apr 20, 2004)

sgltrak said:


> What about one of those electric push trailers?
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Haha, for the pricepoint you're looking at to do a powered rear-hub retrofit, that's not a bad option at all! Then you can avoid the paniers and just use the trailer.


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## fos'l (May 27, 2009)

RickBullottaPA said:


> For a commuter bike, I'd consider it, but for an eMTB, no way. I'd want a purpose-built design with the drive system integrated into the frame properly.


I've got both (Haibike and BBS02 conversion) and I like the DIY better riding off road only. Additionally, if there's ever a problem with the DIY, probably I can diagnose and repair. Hasn't occurred in six years though.


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## Mesozoic (Apr 20, 2004)

I did some research and it sounds like people are very happy with their Bafang mid drive conversions. I've got an old 2008 Felt 29 Elite frame I picked up at the local bike swap for $40 in mint condition a few years back, cobbled together a 1x9 arrangement using spare cranks, BB, pedals, wheels, and crappy disk brakes (Hayes Sole) - the frame is unfortunately a small and I'm 5'10", but after stretching the cockpit out a bit it's not bad for pedestrian pedaling about. I've even ridden this thing offroad on mild trails and it seems to do alright. I ordered a BBS02 kit and will attempt to retrofit this rig.


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## dundundata (May 15, 2009)

I'd say that's a good choice. Nice motor, fairly powerful and light, compact. 

The HD is more powerful and needs a sturdy steed to install on, with powerful brakes, etc.

I haven't tried a hub motor because I figured it would make fixing a flat more of a hassle.


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## Mesozoic (Apr 20, 2004)

Received the BBS02 kit yesterday and couldn't help myself - had to start. Being a 73mm BB, I'm unable to use the nice finishing locknut for the motor assembly, but it'll be more or less concealed by the crank arm anyway. I may redo it with Loctite, however. I had to grind down a portion of the plastic rear derailleur shift cable guide to clear the motor, but it fits pretty well.


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## fos'l (May 27, 2009)

Don't be surprised if the motor loosens. Also Luna, as well as others, sells an arm that should prevent rotation. I just changed mine to a 68 mm frame and haven't had a problem in six years or so.


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## Mesozoic (Apr 20, 2004)

Battery pack doesn't fit in the frame. Might have to look into mounting it on a rear rack or just find a different frame altogether. This one is a small.


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## TNC (Jan 21, 2004)

I'm currently doing a build on the BBSHD and have a question on your comment about the 73mm BB issue. I thought the BBS02 was a 68mm-73mm just like the HD...larger BB fatbike options aside. My bike has a 68mm BB, and I used a 5mm spacer to fill out the difference as the HD comes delivered as a 75mm...which of course still allows 68mm fitment. I'm curious on why your locknut wouldn't fit. I'm no expert on these mid-drives as I'm just getting into them, and maybe there's a slight difference in the BB sizing on the BBS02 that I missed.


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## fos'l (May 27, 2009)

I've never built a BBSHD, so don't know what the BB is like. However, have built several BBS02's and they are fine with 68mm BB's, but haven't been able to use the "jam" nut on 73.


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## TNC (Jan 21, 2004)

fos'l said:


> I've never built a BBSHD, so don't know what the BB is like. However, have built several BBS02's and they are fine with 68mm BB's, but haven't been able to use the "jam" nut on 73.


Yes, in retrospect you're correct...like I said, I'm new to this mid-drive concept. After my post the other day, I played with this 73mm BBSHD in my SC Nomad. It has a 73mm BB and everything works as advertised. After putzing with this motor between my 68mm BB SC Bullit and this 73mm Nomad, I can see the problem. However, I also see this is an accepted formula not to run the aluminum "locknut" in many applications as it's a pants-and-suspenders component rather than a necessary component. Still, I understand one wanting an application where all provided parts are used as they were designed.


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## dundundata (May 15, 2009)

Well parts like the little motor bracket don't work so well. It's supposed to keep the motor in place but you really need to tighten the locknut and even then it can rotate, especially the heavy HD motor. Some sort of bracket like the Luna helps keep everything in place, even if the locknut came loose.

Bafang is not the most refined setup and the installation hardware not the best from the factory.

I recommend loctite on that nut. On my HD build with 73mm BB and luna bracket my little cover doesn't fit either. Though it's very secure with 2 hose clamps and the bracket.


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## Mesozoic (Apr 20, 2004)

I completed the BBS02 retrofit into my Felt Nine Elite which had already been relegated to milder street duty and I'm quite happy with it! I can easily cruise at 25-30 mph with pedal assist. I added a Topeak rear rack in order to mount a pannier for my work laptop and other bits as well as top mounting the battery pack. It's definitely added a fair bit of weight with all of those things, but the bike is very pleasant to ride and commuting on it today so will find out what the battery life/range is (52V Dolphin pack) - I've heard that the motor controller doesn't last particularly long with a 52V pack, but we'll see.


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## dundundata (May 15, 2009)

I haven't had any issues running a 52v battery, the 02 is pretty effecient.


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## minimusprime (May 26, 2009)




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## TNC (Jan 21, 2004)

I'm certainly no expert here, as I'm just getting into the mid-drive conversion on my SC Nomad. However, I think there is info that you can set the controller amperage down to 18 amps or so which apparently preserves the controller in the 02 model Bafang. I'm a long time bike mechanic but a relative greenhorn on these conversions. I read up a ton on the major ebike sites and gleaned a lot info about these motors and options.


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## Old & Slow (May 3, 2020)

dundundata said:


> On my HD build with 73mm BB and luna bracket my little cover doesn't fit either. Though it's very secure with 2 hose clamps and the bracket.


I must have a later version of the BBSHD, my locknut had one thread to spare on my 73mm BB using the lock cap.









Do you have a photo and/or link to the Luna bracket you mention?

Thanks


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## fos'l (May 27, 2009)

Mesozoic said:


> I completed the BBS02 retrofit into my Felt Nine Elite which had already been relegated to milder street duty and I'm quite happy with it! I can easily cruise at 25-30 mph with pedal assist. I added a Topeak rear rack in order to mount a pannier for my work laptop and other bits as well as top mounting the battery pack. It's definitely added a fair bit of weight with all of those things, but the bike is very pleasant to ride and commuting on it today so will find out what the battery life/range is (52V Dolphin pack) - I've heard that the motor controller doesn't last particularly long with a 52V pack, but we'll see.


I've been using a 52V pack for six years in hilly, eroded off road areas with the "old" BBS02 which, reportedly had an inferior controller, with no problems.


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## fos'l (May 27, 2009)

Old & Slow said:


> I must have a later version of the BBSHD, my locknut had one thread to spare on my 73mm BB using the lock cap.
> View attachment 1927221
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Pretty sure the BBSHD is "73 mm compatible", while the BBS02 isn't from the standpoint of using the "jam" nut.


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## dundundata (May 15, 2009)

BSB-1 Stabilizer Bar for BBS02 and BBSHD


Providers of quality ebikes, electric bike batteries, motors and components at affordable pricing.




lunacycle.com





Actually I checked and do have the little cover on. I think initially it wasn't fitting until I bent the bracket a bit.


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## Mesozoic (Apr 20, 2004)

Well, I'd have to say that the retrofit is nothing short of amazing. It's breathed new life into an old bike that was not going to be used and probably scrapped. I rode 17 miles on the greenway with a pannier loaded up with about 20 lbs of gear - no problem cruising at 25-30 mph. I probably need to upgrade the brakes from the crappy Hayes Sole units I have, but I could've done worse and it's hard to beat free. Inspection showed that the motor had moved and the locknut needed tightening so I used some Loctite 271 on the threads and tightened it as much as I could. If it continues to rotate I'll consider purchasing the Luna bracket or perhaps fabricating something myself since I have access to a water jet. I really like the reinforcement that the individual with the light blue Santa Cruz installed on the down tube.

Battery life is no concern at all - I bet I could do a full round trip (34 miles total) on a single charge of the 52V battery. It was ridiculously fun to ride.


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## fos'l (May 27, 2009)

Don't know whether you can shoehorn the motor in the frame, but Wolf has a unit that locates the water bottle mounts where you want them. I was able to fit a battery in the triangle using them. Probably won't fit even with them though.


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