Go Back  Bike Forums > Bike Forums > Folding Bikes
Reload this Page >

Brompton Wiki - Adding electric assistance

Notices
Folding Bikes Discuss the unique features and issues of folding bikes. Also a great place to learn what folding bike will work best for your needs.

Brompton Wiki - Adding electric assistance

Old 07-16-13, 07:53 AM
  #1  
Senior Member
Thread Starter
 
Join Date: Jan 2010
Posts: 433
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 2 Times in 1 Post
Brompton Wiki - Adding electric assistance

Because of the many threads that come up on the Brompton yahoo discussion forum about adding electric assistance and that many of the enthiasts like myself have had to type and re-type replies, I have agreed to update the associated area on the Brompton wiki.

As I am not a reseller hopefully it will be independent, although I must confess that having converted several Bromptons to electric assistance I have my favorite components.

However all my conversion have been DIY from motors sourced directly form China i.e. building wheels and adding electrics rather than purchasing the many kits that are now available.

Its still a work in progress, but I have added a few links at the bottom of the page to kit and component providers.

https://bromptontalk.wikispaces.com/Electric+Assist

There is also a nice video showing exactly how a kit can be fitted. Although it is provided by a specific supplier the process is pretty similar for the various kits available.

In addition much of the information is also transferable to other small wheeled bikes and folders. I myself have also added assistance to a Dahon Uno and a Xootr Swift.

Regards

Jerry

Last edited by jerrysimon; 07-16-13 at 07:56 AM.
jerrysimon is offline  
Old 07-16-13, 10:39 AM
  #2  
Senior Member
 
Still Pedaling's Avatar
 
Join Date: Jun 2013
Location: Arizona
Posts: 806

Bikes: Brompton and Dahon Curve D3

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I enjoyed that first video. It doesn't seem all that difficult really, but what about all that cable hanging down, did he not strap it securely to the cross tube?
Still Pedaling is offline  
Old 07-16-13, 11:36 AM
  #3  
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,598

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,354 Times in 861 Posts
Where does the power torque windup go?

the security hooked washer and the dropout slot seems inadequate.

saw the results of a motor stripping the dropouts of a Motor
retrofitted on a Catrike, .. owner ruined the frame, when 1 end was not fully seated.

he hot-dogged a corner and flipped the trike
I suspect then didn't do adequate safety inspection .

Last edited by fietsbob; 07-16-13 at 11:48 AM.
fietsbob is offline  
Old 07-16-13, 12:08 PM
  #4  
Senior Member
Thread Starter
 
Join Date: Jan 2010
Posts: 433
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 2 Times in 1 Post
The first video is using a heavier more powerful motor and those replacement forks and dropouts are really beefed up. As you say a lot of wiring mess plus I don't like that battery on the seat post.

The second video is where you fit a kit into your existing forks. The wiring and battery is much more subtle being in the bag. This motor is less powerful 180W but adequate and I have used a similar motor for the last 3 years and 6000 miles pretty much daily, without any problems with motor or frame

As stated I am not a retailer of any of the systems listed and have no affiliation with them, but I do buy all the component parts direct from China to make up my own kits. I have converted a few family and friends bikes but pretty much at cost of the parts only.

Regards

Jerry

Last edited by jerrysimon; 07-16-13 at 12:21 PM.
jerrysimon is offline  
Old 07-16-13, 12:28 PM
  #5  
Senior Member
 
Join Date: Jun 2008
Posts: 449
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 14 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Jerry - Thanks for posting this. I have always been intrigued by electric bicycles but have never owned one. From reading your posts in the past, I know that you have explored the world of electric bikes, particularly folders, and I believe that what you have assembled DYI is an ideal arrangement, preferable to what I have seen available as kits or fully outfitted bikes, thanks to the high value you place on light weight.

Maybe someday I will take the plunge, but until then, I will take vicarious enjoyment from your efforts, and those of others.
DoubleDiamonDog is offline  
Old 07-17-13, 06:28 AM
  #6  
Senior Member
Thread Starter
 
Join Date: Jan 2010
Posts: 433
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 2 Times in 1 Post
Originally Posted by DoubleDiamonDog
From reading your posts in the past, I know that you have explored the world of electric bikes, particularly folders, and I believe that what you have assembled DYI is an ideal arrangement, preferable to what I have seen available as kits or fully outfitted bikes, thanks to the high value you place on light weight.
Thanks. I have spent a lot of time and money designing and installing the lightest system possible, but then for me it is a hobby

Given that a Brompton is often purchased for its small fold and portability, I considered minimising the weight of any electric assistance is important. Maintaining/not compromising the fold is also one of the other big challenges when retrofitting e assist.

After three years of tinkering this is my final solution for lightweight portable e biking.




An M2L-X with motor fitted that weighs 11.5kg (same as a stock M3L) in terms of carrying with battery and controller in the bag.

Not cheap, but by far my most successful portable conversion.

Regards

Jerry
jerrysimon is offline  
Old 07-17-13, 09:04 AM
  #7  
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,598

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,354 Times in 861 Posts
they all require spreading the forks to 10+?
fietsbob is offline  
Old 07-17-13, 12:40 PM
  #8  
Senior Member
Thread Starter
 
Join Date: Jan 2010
Posts: 433
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 2 Times in 1 Post
The 80mm wide motors I use, require about 5-6mm spread though in practice wider as they spring back.

The dropouts also need to be opened out from 8mm-10mm to accept the flat of the motor shaft i.e. about 1mm on each edge.

All shown in the video on the wiki.

Jerry
jerrysimon is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
bent4me
Folding Bikes
12
02-05-21 08:58 AM
BruceMetras
Folding Bikes
19
12-29-15 10:41 AM
Kevin Harvey
Electric Bikes
6
12-17-12 03:42 AM
romanmar
Electric Bikes
2
06-10-12 12:32 PM
wandt
Folding Bikes
2
11-09-10 09:32 PM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.