Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

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.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 08-11-17, 12:35 PM   #1
rec
Member
Thread Starter
 
Join Date: Jul 2006
Location: sfbay
Bikes: peugot mixte, roger, p21, raleigh sscx, rockhopper, sycip, centurion
Posts: 36
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 8 Post(s)
Brompton crankset variations

I've noticed stock Bromptons with two different types of drive side cranks: spiderless crank with cheapy looking chainring and integrated chainguard; crankset with 5-arm spider (w/ hidden arm) 130 bcd replaceable chainring and integrated chainguard.

Was there a change to the 130 bcd crank recently and only old builds have the cheapy looking spiderless crank?
rec is offline   Reply With Quote
Old 08-11-17, 12:41 PM   #2
HGR3inOK 
Senior Member
 
Join Date: Apr 2009
Location: Oklahoma, U.S.A.
Bikes: Brompton H6L-X, Dahon Curve D3
Posts: 792
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 38 Post(s)
Quote:
Originally Posted by rec View Post
I've noticed stock Bromptons with two different types of drive side cranks: spiderless crank with cheapy looking chainring and integrated chainguard; crankset with 5-arm spider (w/ hidden arm) 130 bcd replaceable chainring and integrated chainguard.

Was there a change to the 130 bcd crank recently and only old builds have the cheapy looking spiderless crank?
Brompton went to the "spider" crank in model year 2013. The change was not on some early 2013s due to parts availability issues. Most Bromptons can be upgraded to the spider crank with the replaceable chainring.

-HANK RYAN-
Norman, Oklahoma USA
__________________
DISCLOSURE: I have an ownership interest in a company that is an authorized dealer for Brompton.
HGR3inOK is offline   Reply With Quote
Old 08-11-17, 12:51 PM   #3
rec
Member
Thread Starter
 
Join Date: Jul 2006
Location: sfbay
Bikes: peugot mixte, roger, p21, raleigh sscx, rockhopper, sycip, centurion
Posts: 36
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 8 Post(s)
Thanks, Hank!
rec is offline   Reply With Quote
Old 08-12-17, 06:54 AM   #4
12boy
Senior Member
 
12boy's Avatar
 
Join Date: Oct 2012
Location: casper wy usa
Bikes: brompton sl, surly steamroller, fuji track, gary fisher bmx minivelo etc
Posts: 252
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 78 Post(s)
The cheapy cranks are lighter than the ones with replaceable chain rings. They have two disadvantages...when the teeth are worn they must be thrown away and you are stuck with only one size choice. I have used both on my Brompton, though, and the cheapy one is my current choice, partially to offset the weight of the IGH hub and my leather saddle. In over 5000 miles I have not succeeded in either wearing it out or breaking it, although I am fairly light and don't stand up and mash the gears a lot.
12boy is offline   Reply With Quote
Old 08-12-17, 09:34 AM   #5
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 8
Posts: 26,437
Mentioned: 44 Post(s)
Tagged: 0 Thread(s)
Quoted: 2396 Post(s)
the original Stronglight supplied cranks were their standard component for many years.. 3 sizes , 44, 50, 54t.

people bolted on smaller chainrings to the outside with some of the extra holes, for climbing gears,
only to find the swaged on arm spun separately from the chainring..

any 3 piece crank can do , the chainline is rather close in. to dictate what spindle length be used with your choice of cranks..

...even fit a double chainring set..




....




....

Last edited by fietsbob; 08-12-17 at 09:40 AM.
fietsbob is offline   Reply With Quote
Old 08-13-17, 09:11 PM   #6
1nterceptor
LET'S ROLL
 
1nterceptor's Avatar
 
Join Date: Nov 2009
Location: NEW YORK, NY - USA
Bikes: 2014 BMC Gran Fondo, 2013 Brompton S6L-X
Posts: 4,141
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 96 Post(s)
Quote:
Originally Posted by 12boy View Post
The cheapy cranks are lighter than the ones with replaceable chain rings. They have two disadvantages...when the teeth are worn they must be thrown away and you are stuck with only one size choice. I have used both on my Brompton, though, and the cheapy one is my current choice, partially to offset the weight of the IGH hub and my leather saddle. In over 5000 miles I have not succeeded in either wearing it out or breaking it, although I am fairly light and don't stand up and mash the gears a lot.
My 2013 has the spider cranks; pretty sure it's lighter than the old style. Dura Ace ring and protector removed.
I think the bottom bracket is different for each style as well.
__________________
Lite That Never Goes Out: https://www.youtube.com/watch?v=w-0p...6zPoymgKaIoDLA
1nterceptor is offline   Reply With Quote
Old 08-14-17, 09:47 AM   #7
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 8
Posts: 26,437
Mentioned: 44 Post(s)
Tagged: 0 Thread(s)
Quoted: 2396 Post(s)
The spider crank is machined to only take one chainring on the back side.. as shown..
fietsbob is offline   Reply With Quote
Old 08-16-17, 06:31 AM   #8
MultiplexMan
Junior Member
 
Join Date: Dec 2005
Location: Sydney
Bikes: BF NWT, BF Fixie, Danon Mu Uno, Dr Hon Mu Uno
Posts: 8
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
The current spider crank set utilises a JIS square taper BB. You can replace the stock Brompton JIS BB with Shimano UN55 in 118 or 122,5.

The earlier spiderless crank set utilised an ISO square taper BB.

I have also fitted various Shimano (XT M785, Octalink Ultegra & DuraAce) and FSA (SLK MegaExo & ISIS) cranksets without issue.
MultiplexMan is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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



All times are GMT -6. The time now is 04:39 PM.


 
  • Ask a Question
    get answers from real people!
Click to start entering your question.
I HAVE A QUESTION