Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Can't find 42mm chainline crankset in UK

Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Can't find 42mm chainline crankset in UK

Old 08-22-19, 03:13 AM
  #1  
howieleem
Member
Thread Starter
 
Join Date: May 2013
Location: London UK
Posts: 45
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 8 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Can't find 42mm chainline crankset in UK

Hi
I have an old English frame with 120mm rear dropouts (widened from 110mm)
The distance from the rear sprocket to the right-hand dropout 18mm, so I have a chainline of 42mm.
I have a bottom bracket 68mm x 103mm JIS.
Problem is I cannot find a low-cost 42mm chainline crankset in the UK. The only thing I can find is an Origin8 crankset from the USA.

Any ideas?

Last edited by howieleem; 08-22-19 at 03:24 AM. Reason: mistake
howieleem is offline  
Old 08-22-19, 09:13 AM
  #2  
cpach
Senior Member
 
Join Date: Oct 2009
Location: Mt Shasta, CA, USA
Posts: 1,177

Bikes: Too many. Cannondale SuperSix, Trek Remedy 8, Trek Crossrip+ get the most ride time.

Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 237 Post(s)
Likes: 0
Liked 15 Times in 13 Posts
Get a bottom bracket with an appropriate length spindle to match your chainline with whatever square taper crankset and/or shim out the chainring with spacers. Done.
cpach is offline  
Old 08-22-19, 09:32 AM
  #3  
Unca_Sam
The dropped
 
Unca_Sam's Avatar
 
Join Date: Oct 2018
Location: Columbus, OH
Posts: 267

Bikes: Pake C'Mute Touring/Commuter Build

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 108 Post(s)
Likes: 0
Liked 40 Times in 33 Posts
Make your chainline 51 mm with spacers at the rear

Originally Posted by cpach View Post
Get a bottom bracket with an appropriate length spindle to match your chainline with whatever square taper crankset and/or shim out the chainring with spacers. Done.
My first thought was "How do you shim a square taper BB?" Then, "Can you shim a square taper BB??"

You mean, shim out the cogs in the back though, don't you. Here's why:

With the current setup, simple math says that a 42 mm chainline is only 8 mm wider than your BB shell, and the small spindle (Dura-Ace?) you're using is overshooting the chainline by 9mm. You can't change the crankset or chainrings, they have to sit against the taper firmly. Therefore, move your cassette or freewheel or single cog right 9 mm, since you have 18mm there.

Last edited by Unca_Sam; 08-22-19 at 09:47 AM.
Unca_Sam is offline  
Old 08-22-19, 09:37 AM
  #4  
trailangel
Senior Member
 
trailangel's Avatar
 
Join Date: Feb 2014
Location: Pasadena, CA
Posts: 3,790

Bikes: Schwinn Varsity

Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 1361 Post(s)
Liked 95 Times in 63 Posts
In UK search for Chainset instead of Crankset.
They don't sell them by the chainline.... that's up to you, the installer.
trailangel is offline  
Old 08-22-19, 09:57 AM
  #5  
Unca_Sam
The dropped
 
Unca_Sam's Avatar
 
Join Date: Oct 2018
Location: Columbus, OH
Posts: 267

Bikes: Pake C'Mute Touring/Commuter Build

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 108 Post(s)
Likes: 0
Liked 40 Times in 33 Posts
Blast from the past

Bottom Bracket for 42mm Chainline W/ Origin 8 Crankset?

This thread from a decade ago seems to have dealt with similar issues. Please confirm if you're using a SS or Fixed setup.

42 mm chainline? What's the point?

An older one proposes additional solutions. I agree with trying to respace the cog. I realize that your front chainline is likely less than 51.5mm, but you'd have to provide that info.

Last edited by Unca_Sam; 08-22-19 at 10:02 AM.
Unca_Sam is offline  
Old 08-22-19, 10:20 AM
  #6  
cpach
Senior Member
 
Join Date: Oct 2009
Location: Mt Shasta, CA, USA
Posts: 1,177

Bikes: Too many. Cannondale SuperSix, Trek Remedy 8, Trek Crossrip+ get the most ride time.

Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 237 Post(s)
Likes: 0
Liked 15 Times in 13 Posts
Originally Posted by Unca_Sam View Post
My first thought was "How do you shim a square taper BB?" Then, "Can you shim a square taper BB??"

You mean, shim out the cogs in the back though, don't you. Here's why:

With the current setup, simple math says that a 42 mm chainline is only 8 mm wider than your BB shell, and the small spindle (Dura-Ace?) you're using is overshooting the chainline by 9mm. You can't change the crankset or chainrings, they have to sit against the taper firmly. Therefore, move your cassette or freewheel or single cog right 9 mm, since you have 18mm there.
You can shim the chain rings, not the bb
cpach 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

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