Go Back  Bike Forums > Bike Forums > General Cycling Discussion
Reload this Page >

Does bottom bracket width matter on a single speed conversion?

Notices
General Cycling Discussion Have a cycling related question or comment that doesn't fit in one of the other specialty forums? Drop on in and post in here! When possible, please select the forum above that most fits your post!

Does bottom bracket width matter on a single speed conversion?

Old 08-12-20, 07:39 PM
  #1  
crankholio
Senior Member
Thread Starter
 
crankholio's Avatar
 
Join Date: Aug 2020
Location: Trapped near the inner circle of fault
Posts: 85
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 34 Post(s)
Liked 19 Times in 14 Posts
Does bottom bracket width matter on a single speed conversion?

Assuming the chain line is straight, does the bottom bracket width make much of a difference? I ask because I recently replaced a 118mm with a 122.5mm, since it's what I had on hand. I moved the spacers on the freehub to adjust the chain line accordingly. I was going to post an image to show how much spindle is visible between the BB shell and the crank arms, but the forum won't allow it.
crankholio is online now  
Old 08-12-20, 08:30 PM
  #2  
bwilli88 
Senior Member
 
bwilli88's Avatar
 
Join Date: Jan 2013
Location: Kampong Cham, Cambodia but I have quite a few in Lancaster, PA
Posts: 2,336

Bikes: Bikes in USA; 73 Raleigh Supercourse dingle speed, 74 Raleigh Grand Prix SS, 78 Raleigh Supercourse, 83 Centurion Pro-Tour, 82 Raleigh RRA.

Mentioned: 50 Post(s)
Tagged: 0 Thread(s)
Quoted: 603 Post(s)
Liked 208 Times in 145 Posts
Not really, it sound like you are using a freehub with a single cog and a bunch of spacers. If you were using a single cog freewheel it could be a problem.
Having an arrow straight chainline is not necessarily crucial to have but it will tend to wear out the chain a bit quicker.
bwilli88 is offline  
Likes For bwilli88:
Old 08-12-20, 08:43 PM
  #3  
Gresp15C
Senior Member
 
Gresp15C's Avatar
 
Join Date: Sep 2014
Posts: 3,149
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 812 Post(s)
Liked 235 Times in 172 Posts
To make use of a particular random selection of parts -- Bendix hub and whatever BB and crank were on hand -- I dished the rear wheel by a few mm.
Gresp15C is offline  
Old 08-13-20, 06:21 AM
  #4  
c_m_shooter
Senior Member
 
c_m_shooter's Avatar
 
Join Date: Sep 2006
Location: Paradise, TX
Posts: 1,781

Bikes: Soma Pescadero, Surly Pugsley, Salsa Fargo, Schwinn Klunker, Gravity SS

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 71 Post(s)
Liked 86 Times in 66 Posts
If youwere using a freewheel or track hub, the BB width would matter. Since you are using a freehub with spacers, it doesn't matter.
c_m_shooter is offline  
Likes For c_m_shooter:
Old 08-13-20, 07:11 AM
  #5  
ofajen
Cheerfully low end
 
Join Date: Jun 2020
Posts: 364
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 102 Post(s)
Liked 160 Times in 99 Posts
Originally Posted by Gresp15C View Post
To make use of a particular random selection of parts -- Bendix hub and whatever BB and crank were on hand -- I dished the rear wheel by a few mm.
Yeah I just did this sort of thing last weekend. Undished the rear wheel by roughly 6 mm to change the chainline from running a 7-speed to a single speed. A 5-speed would line up nicely now, too. OLD is still about 126 mm.

Funny thing is that in doing so, a rim that I was somewhat annoyed by is now running truer and rounder again. Plus itís such a blast running the bike SS. 😊

Otto
ofajen is online now  
Likes For ofajen:
Old 08-13-20, 07:58 AM
  #6  
DrIsotope
Non omnino gravis
 
DrIsotope's Avatar
 
Join Date: Feb 2015
Location: SoCal, USA!
Posts: 8,467

Bikes: Nekobasu, Pandicorn, Lakitu

Mentioned: 119 Post(s)
Tagged: 0 Thread(s)
Quoted: 4821 Post(s)
Liked 1,561 Times in 879 Posts
The advantages of "doing it wrong." I spread my cheap steel frame from 120mm to 135mm, and run a set of MTB wheels-- many spacers on the hub to set the chainline. Having to set the chainline from the crank seems like a hassle-- obviously doable, but not as easy as having a stack of freehub spacers to choose from.
__________________
DrIsotope is offline  
Old 08-13-20, 08:41 AM
  #7  
fietsbob
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 1,284 Times in 801 Posts
Originally Posted by crankholio View Post
Assuming the chain line is straight, does the bottom bracket width make much of a difference? I ask because I recently replaced a 118mm with a 122.5mm, since it's what I had on hand. I moved the spacers on the freehub to adjust the chain line accordingly. I was going to post an image to show how much spindle is visible between the BB shell and the crank arms, but the forum won't allow it.
You are talking BB spindles they are chosen with the crank arms used..

the BB shell width ... 70, (Italy) 68 (most others) 73 (mountain bikes)
fietsbob is offline  

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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.