On-One Fatty 750W Bafang mid drive build.

[Realtwin]

Here is the progress and development of the On One Fatty 750W Bafang mid drive that I have built for my dad.

I'll start this thread with a big thank you to Doug Snyder of California e-bike, as without his help and generosity in sharing his parts for the 100mm wide conversion, this bike probably wouldn't have come about. At least not with the Bafang drive. http://california-ebike.com/

It developed from my dad loving the look of the big fat tyres but not having the fitness to get over the local hills around us. So, I thought why not build him an electric assist fat bike? How hard can that be?

It started last October with the purchase from On-One in the UK of a fatty with carbon forks and a few other nice components, which came in the biggest bicycle box I have ever seen

https://drive.google.com/file/d/0B-NweBO6XNEUekVHR2RDZmtoLU0/view?usp=sharing

I had decided on a mid drive over hub so took the plunge and bought the 750W Bafang mid drive from Eclipse bikes in the UK. I also bought their 11AH battery and the hydraulic brake sensors.

I had done some research and knew that the bottom bracket sizes were different and had found a conversion for the Bafang in the USA made by California e-bike. The main issue for me was the expense as the conversion is only available as a complete unit due to the CNC machining required. So after some interesting discussions with Doug Snyder of California e-bike he agreed to sell me the parts in kit form for me to adapt without the CNC machining. I waited excitedly for them to arrive and clear customs (took five days alone, two days longer than them arriving from the USA)

I then completed the Bafang shaft extension as shown below.

Firstly it was stripped down. I made a castleated nut for removal but you could use circlip pliers.

https://drive.google.com/file/d/0B-NweBO6XNEUSDktaDJFdlUwc2M/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUSkpsV0NGQ2d4RTg/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUTGQ4VmFmRGJZOHM/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUcERYYnBIMndEQ0U/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUaWtOOEw4OVBjckE/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUTXdGQUNXZWlIbWc/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUbXhfbzdwdC00RVE/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEURWFDMTExZlVfekk/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUYk92QXZyY2Q2R00/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUWGYxR0dYU1dzRmc/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUR0FVbHZNcy1oVm8/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUbmw0YlhaMWRmR2M/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUVVFud0REUHI0ZDg/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUbllQRF9wVUtwUHM/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUazhremVWX1VGQW8/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUUXNRSmlfSXM3VTA/view?usp=sharing

I haven't gone into mega detail of the strip down and re-assembly of the motor as there are videos on You tube already. I machining the threaded tube extender down to the correct size for pressing it into the mid drive.(If this becomes a kit then this will already be done for you) I pressed it in and then held it with a piece of threaded bar and some washers. I then drilled and tapped four holes and loctited four M6 grub screws in which will stop it getting pulled out or moving. I then fitted the longer shaft and put it all back together. Very pleased with myself and the quality of the parts Doug had sent.

Next up was to fit it to the bike, so out came the Double chainring crank and the bottom bracket and in went the Bafang..........................not quite that easy.

The motor gear casing was hitting the chainstays and sticking out 6mm more on the drive side.

https://drive.google.com/file/d/0B-NweBO6XNEUYTItWXFYMGVRN2c/view?usp=sharing

I was loathed to do it especially on a brand new bike, but out came the hammer and some round bar. I (as carefully as you can be with a hammer) adjusted the frame clearance as much as I dared without getitng silly with the force I had to use. Unfortunately it did crack the paint though, which posed another problem in trying to locate some touch up paint, I ended up trying some Honda pearl whites and got close on the second try. Maybe I should have tried a custom made touch up but the paint code is an Asian standard so I wasn't sure about getting it made in the UK. It is hardly noticeable behind the gear case anyway.

https://drive.google.com/file/d/0B-NweBO6XNEUODBXUXVWY3VZZ3M/view?usp=sharing

I also filed some material from the Bafang gearcase at the point were it touches the frame. All of this got me to the motor sticking out 2mm instead of 6mm. Without cutting the frame and welding this was as far as I would go. So I made a 2mm ring spacer for the motor and some 2mm longer tube spacers for the Bafang clamp.

https://drive.google.com/file/d/0B-NweBO6XNEUemZjNFdjOGtkY1E/view?usp=sharing

That was the motor fitted to the frame. Next problem was the chainline and chainring. The Bafang chainring fouled on the chainstays and was too big for the gearing on the fat bike. I also needed to try and get back the 2mm that I had lost with the motor sticking out. I decided to remove the plastic gear cover and get a 0.5mm stainless steel plate laser cut and to machine a chainring carrier to move the chainring in as far as I could. Some turning on the lathe and an unfortunate wait of three and a half weeks for the laser cut part (made in India...............!) and I was getting close. I painted the plate black, bonded it on using loctite 5980 flange sealant and bonded a 4mm O ring seal on.

https://drive.google.com/file/d/0B-NweBO6XNEUT28xZW9pM2U1ME0/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUU1p6V3NXUy1rVzQ/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUS096RTROdDNDVEE/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEURkdpRzJaazFwQjQ/view?usp=sharing

Once fitted to the bike I found that I had got the chainline back to the same as the outer chainring on the original crank.

Onto the electrics, I did my best to keep the install as neat as possible. The battery had to be dis-assembled to get it into the frame but was worth the effort as I didn't want it on a rack. The rest of the install went straight forward and I was finally left with the brake sensors to sort out on the hydraulic discs. After two half days of trial and error and pulling my hair out, I was getting an intermittent error code on the Bafang ER 30 which isn't in the manual. Sometimes the switches would work and then I'd get the error message. I contacted Eclipse bikes and was told that the sensors were not suitable for the 48v Bafang drive. The correct ones will arrive in March/April. So I took the cable operated switches apart and have glued them to the brake levers for now, it is a bit rough for my liking but will do for now, it gets the bike useable.

https://drive.google.com/file/d/0B-NweBO6XNEUdFdGcm9rb1VLcVE/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUc1M2UVU5WldrdzQ/view?usp=sharing

I added a Rolls saddle for that British bespoke look and because my dad ran his own hand made leather good business a while back.

So here is the finished (for now) bike.

https://drive.google.com/file/d/0B-NweBO6XNEUdlVvUWRKMVB6a2s/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUd1FiU1dlSFBYMTQ/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUUGFjVlhIZFE5UHc/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUV0Jhdl9xc3JaWEU/view?usp=sharing

https://drive.google.com/file/d/0B-NweBO6XNEUa3pwd0RobjdDdFE/view?usp=sharing

I will probably post more pictures and will be happy to discuss all the aspects of the conversion, be patient with me responding as I don't always have a lot of time on my hands. I have four spare laser cut plates and O rings which I can sell if anyone needs one, and I also have some parts in the pipeline for the Bafang motor to replace my original chainring carrier.

https://drive.google.com/file/d/0B-NweBO6XNEULVhCR1VpUHNzSE0/view?usp=sharing

I'm nearly up to speed on my CNC CAD/CAM software and design.

 

[Realtwin]

Sorry that the pictures need clicking on. I'll try and work out how to get them up without the links. I used to use image shack for the picture hosting on other forums I go on, but they want a subscription now so I thought that I'd use my google drive. I'm sure that someone on here will point me in the right direction.

 

[Ade]

Nice looking bike - a pity you had so much hassle to fit Doug's conversion kit though. Mine went straight on without a problem.

 

[Realtwin]

Nice looking bike - a pity you had so much hassle to fit Doug's conversion kit though. Mine went straight on without a problem.

I must point out that fitting Doug's conversion to the motor was no problem. I had a prototype set up that I modified he now has his own way of doing it. It was the On-One frame that caused the issues. It will be the same for most people converting to 100mm BB some frames will work and some won't. It would be easy for On-One to start building in clearance at the manufacturing stage of their frames. I think that electric bikes are going to become more and more popular, converting a fatbike extends their use.

 

[Spottydog]

I had my hydrau;ic cut off sensors from Eclipse your in UK like me, I get a blank screen and ER30 code, if I run motor off throttle and brake I get ER04
code when brake is released after 2 second the display reappears as normal.
My motor is a 36v BBS 01 will ring and see what they say monday, have you made any progress with your brake sensor yet or are you still running you temp set up.
A note of caution to othes I got an On One inbred 26 frame and regret buying it,having built my own bike around a Surly troll frame for a semi fat bike this bike is for my girlfriend to use for work and when we ride out together,she wanted normal tyres and the frame looked a good buy at £199.
On paper it sounded ideal 68mm BB and I wanted to use her rock shox recon gold forks and BB7 brakes, the forks fit fine however the rear BB7 does not hence I ended up going to a hydraulic brake with a 140mm rotor.
the motor housing hits the chainstay! "sound familiar" and had to be spaced out 5mm, I decided to use a 42T alcedoitalia inset chainring for best chainline to the N360 hub the chainring teeth just clear the chainstay.
Sos not meaning to hijack your thread just venting off a little steam about on one frame design, my last hurdle to finishing this build is brake cutouts for the hydraulic brake as it would be nice to have the back and front brake as a matched pair shimano slx. If not it will have to retain the BB7 up front and use the cutout lever from kit, love your fat bike build and detail/pics included.

 

[KINNINVIEKID]

I use Photobucket for free photo hosting then just copy the img code straight here
looking good but I agree its a pain in the but when the chainline is out.
My Cannondale has a 73mm bb and the chainline is perfect,I was worried the chainring(46t) would hit the chainstay but it was 1mm off and now its running 44t so spot on.

 

[spinningmagnets]

If you resize the pics so they are smaller than 512 kb they should show up. I have found that shrinking them to 600 X 400 (or smaller) usually works.

 

[Realtwin]

Hi Spottydog

My new sensors have arrived on Saturday from Eclipse. I haven't looked at fitting them yet. As you know the size and shape isn't great for hiding neatly out of the way. While my temporary set up isn't how I'd like to leave it it is working well and my dad is using the bike a lot, which was the whole idea.
As for your frame issues I feel your pain, it looks to be pot luck even with a 68mm BB! I certainly wouldn't advise people to do what I did and massage (dent) the frame in a bit but I was willing to take the chance. I really think electric bikes are here to stay and will become massive in the near future with the commuter market especially. I was going to give On One some info and to see if they would consider adding frame clearance to some of their bike frames (it would be easy to do at the manufacturing stage), If they don't then I think that they will be missing missing a trick especially with the fat bikes.
I'll update this thread when I use the correct brake sensors with however I mount them as it might help others.

Hi Kinninviekid, Spinning magnets.
thanks for the info, I have used a resizing software recommended by another forum user to lower the size and resolution of the pictures. I have made another file and I will add them under the existing links when I have a bit of time, so that the option is there to see the bigger hi res photo's too.

Thanks for the positive comments about the bike, it get's noticed a lot when it is out and about. One poor roadie went past out of breath asking if it had a bloody motor on, which made my dad smile and say "it might have".

 

[Spottydog]

Good luck working something out will do likewise if I come up with a solution, have emailed eclipse but had no reply yet and they don't have a contact number on website. I have a 750w 48v motor on my bike the switches did the same thing as they did on my 350w 36v build, ER30 code when brake applied.The motor will not run without a sensor plugged into brake cutout lead so for now have retained the BB7 caliper on the front and using the brake lever supplied with kit.
For the hydrulic rear have just plugged in one of the eclipse cutout sensors with the magnetic washer taped to the end of it so motor runs and the front brake cuts the power not ideal but ok for now.
I doubt planet x / On one will be much interested in frame improvments as for normal bike use the frame is prob ok, I thump my tub about the great future ahead of e bikes it largely gets blank stares of disinterest, even my other half isn't really convinced she needs this bike am sure that will change when she gets the hang of riding it tho.
Her 350w is similar spec to mine running N360 hub and a retro fit harmony electric gear shift kit, I love how it rides the motor assists the gears sort themselves out you just enjoy a very easy riding experience no jolts, crunching or mis shifts or puffing for breath, e biking how it should be.
Fat bikes rock I love ur build, I bottled it and built semi fat but one big benifit was the standard BBS motor fitted in BB and the Surly frame gave non of the issues I had with the On one inbred frame.

 

[Realtwin]

Good luck working something out will do likewise if I come up with a solution, have emailed eclipse but had no reply yet and they don't have a contact number on website. I have a 750w 48v motor on my bike the switches did the same thing as they did on my 350w 36v build, ER30 code when brake applied.The motor will not run without a sensor plugged into brake cutout lead so for now have retained the BB7 caliper on the front and using the brake lever supplied with kit.
For the hydrulic rear have just plugged in one of the eclipse cutout sensors with the magnetic washer taped to the end of it so motor runs and the front brake cuts the power not ideal but ok for now.
I doubt planet x / On one will be much interested in frame improvments as for normal bike use the frame is prob ok, I thump my tub about the great future ahead of e bikes it largely gets blank stares of disinterest, even my other half isn't really convinced she needs this bike am sure that will change when she gets the hang of riding it tho.
Her 350w is similar spec to mine running N360 hub and a retro fit harmony electric gear shift kit, I love how it rides the motor assists the gears sort themselves out you just enjoy a very easy riding experience no jolts, crunching or mis shifts or puffing for breath, e biking how it should be.
Fat bikes rock I love ur build, I bottled it and built semi fat but one big benifit was the standard BBS motor fitted in BB and the Surly frame gave non of the issues I had with the On one inbred frame.

Your build looks good and is a bit more practical than the full fat bike. It does add a fair bit of expense and hassle with the 100mm BB. Oddly I found that my 48v Bafang worked fine without the brake sensors plugged in, I did contact Eclipse about it but just got told that the new ones would be available soon. The 750w is good and powerfull, my dad nearly flipped it when he accidentally caught the throttle while not sitting on it. I think he gets on now and then switches it on. I think for commuting electric will get more people on bikes, if I was to put a 750w kit on my road bike I could easily keep up with the traffic around town although it is just for off road :wink: It might help my Strava times a bit too.

 

[GameOverMan]

Quick question. I have the same bike that I'm trying to convert. I'm in planning phase now and wondering what should I do because I don't quite understand the issue with it. Would it fix the problem if I buy a 120mm unit? And just use spacers on both sides?

Thanks!

 

[Realtwin]

Quick question. I have the same bike that I'm trying to convert. I'm in planning phase now and wondering what should I do because I don't quite understand the issue with it. Would it fix the problem if I buy a 120mm unit? And just use spacers on both sides?

Thanks!

Hi GameOverMan
The main issues at the time was that there wasn't a 100mm BB or 120mm BB conversion. Doug did the 100mm conversion and offered it as a kit or full complete motor conversion which was brilliant as is it gave me a chance to convert the fatty.
The problem with the On One fatty frame is that the Bafang gearcase hits the frame and sticks out too far, 6mm on the chain side. This affects both the chain line and the Q factor for pedaling. With all the work I did I got it down to 2mm for the Q factor and the chainline back to where it was on the big ring. This means that you can still use all the gears for pedaling and the lower 7 of the 10 with the motor.
I don't know how the 120mm BB conversion will fit as I don't have any experience with it. Yes two 10mm spacers should offer a quick solution for fitment to the frame without the clearance issues and keep the Q factor. But it might leave you with very limited gears due to the chainline. As far as I know there are two standards for rear wheel hub width, again the fatty is the narrower of the two, leaving less to play with on the chainline.

I hope that this information is helpful.

Regards

Andrew

 

[GameOverMan]

Gotcha, well I don't have any experience with conversions but I'll give it a shot. I ordered a 120mm motor with spacers because I saw a video where a guy had to cut a piece of bottom bracket of his frame when he was installing 100mm one. I didn't think about gearing issue so I guess I would have to figure it out when I get it. Is there anything I can do to align it with gears properly? Maybe spacers for those gears/sprockets? I'm really new to this.

Any advice will go a long way.
Thanks.

 

[Realtwin]

You will have to get the motor fitted and then decide on chainring size and see where it lines up with the cassette. I'd think that you would get some of the gears. You won't know until it's all fitted. Good luck.