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 11-12-17, 12:12 PM   #1
hennypenny308
Newbie
Thread Starter
 
Join Date: Nov 2017
Bikes:
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Why changing 50T chainring to smaller 44T chainring is heavier?

Why does changing the standard 50T chainring to the smaller 44T chainring make the bike heavier? This is on the Brompton bike builder webpage.
I just assumed that the smaller 44T ring should weigh less than the larger 50T ring.
hennypenny308 is offline   Reply With Quote
Old 11-12-17, 12:15 PM   #2
dabac
Senior Member
 
Join Date: Mar 2008
Bikes:
Posts: 7,272
Mentioned: 27 Post(s)
Tagged: 0 Thread(s)
Quoted: 623 Post(s)
Steel vs aluminium perhaps?
dabac is offline   Reply With Quote
Old 11-12-17, 02:23 PM   #3
badmother
Senior Member
 
badmother's Avatar
 
Join Date: Nov 2007
Bikes:
Posts: 3,730
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 260 Post(s)
Old crankset being lighter (one piece) than the newer one where you can change out the chainring?
badmother is offline   Reply With Quote
Old 11-12-17, 02:48 PM   #4
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 8
Posts: 29,105
Mentioned: 65 Post(s)
Tagged: 0 Thread(s)
Quoted: 3184 Post(s)
Yes, both are good reasons, Ive seen a steel chainring fixed crank arm set in old SJS cycles parts for brompton listings

too bad the OP did not provide a link to their information source...

the 130 bcd current spider crank arm does take non brompton chainrings, a 39t (without the trouser guard) will weigh less than the B 50t with.


Chasing the gram shaving on your bike order? after its yours you can put that carbon fiber composite.. crankset on..

then all the after market Titanium hardware offered ..






..

Last edited by fietsbob; 11-12-17 at 03:00 PM.
fietsbob is offline   Reply With Quote
Old 11-12-17, 03:01 PM   #5
Rapido
Green lights for all
 
Rapido's Avatar
 
Join Date: Aug 2005
Location: Ohio, Germany, Florida, West Virginia, and then Georgia now
Bikes: Fuji Team SL 20 speed, Nishiki, Mercian 12 speed. Alan 10 speed, Frejus, Bauer, Morobecane, Schwinn, JC Higgins 3 spd, Columbia coaster brake,
Posts: 98
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
The foldable bikes with smaller wheels should have bigger chainrings so the gear ratios/inches make up for the smaller drive wheels. My foldable bike has 20" tires and I have (lucky) a chainring 60t. Sooo my highest gear is 85" gear inches. THAT allows me to keep up with the old fashioned "big wheeled" bikes on regular group trips. Also the pedal cranks must have the same length as other bikes for adultz, 170+ mm. These foldable bikes are verrry practical!
Rapido is offline   Reply With Quote
Old 11-12-17, 03:15 PM   #6
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 8
Posts: 29,105
Mentioned: 65 Post(s)
Tagged: 0 Thread(s)
Quoted: 3184 Post(s)
there is the 3 speed hub , with an overdrive 3rd gear, of 4/3 so a 13t cog acts like its a 9.7tooth ..




.....
fietsbob is offline   Reply With Quote
Old 11-12-17, 08:52 PM   #7
reppans
Senior Member
 
Join Date: Dec 2006
Location: New England
Bikes: Brompton M6R, Specialized Tricross Comp, Ellsworth Isis, Dahon Speed P8
Posts: 550
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 210 Post(s)
I have both 50 and 44 tooth chain rings and they look the same to me apart from size. I think it's a glitch in the Brompton Builder software programming or specs - if there is an actual difference in weight, I'd be surprised if would make the tenth of a pound rounding.
reppans is offline   Reply With Quote
Old 11-13-17, 02:05 AM   #8
hennypenny308
Newbie
Thread Starter
 
Join Date: Nov 2017
Bikes:
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
I'll speak to Brompton to get clarification. They are made from the same material, so it makes sense that a smaller ring should weigh less. I think the most likely explanation is a glitch in the Bike Builder software. I'm not the strongest cyclist and I wanted to get either a single speed or 2 speed with the smallest chainring 44T, so that I can have a nice relaxing ride on the flat and still be able to climb a small slope.
hennypenny308 is offline   Reply With Quote
Old 11-13-17, 12:21 PM   #9
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: 4,298
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 148 Post(s)
Smaller ring/protector, shorter chain = should be lighter.
I have some weights listed towards the end of my video:
__________________
WHY USE JIS DRIVERS ON JAPANESE COMPONENTS: https://www.youtube.com/watch?v=uL7H...6zPoymgKaIoDLA
1nterceptor is online now   Reply With Quote
Old 11-16-17, 02:26 PM   #10
hennypenny308
Newbie
Thread Starter
 
Join Date: Nov 2017
Bikes:
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Brompton's bike builder has not been updated since 2012. There are some errors, for instance, the reduced gearing should be -12% and -18% (not -19%). The explanation for the weigh discrepancy is another error.
Today, after trying out a 6 speed, I found the 2nd and 4th gears best suited me, so I opted for a 2 speed with -18% gearing.
hennypenny308 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 10:39 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    get answers from real people!
Click to start entering your question.
I HAVE A QUESTION