Singlespeed & Fixed Gear "I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"-- Henri Desgrange (31 January 1865 - 16 August 1940)

First fixie build

Reply

Old 10-11-18, 07:08 AM
  #26  
j_e_r_e_m_y
Minor Annoyance
 
j_e_r_e_m_y's Avatar
 
Join Date: May 2015
Location: Milwaukee
Posts: 199

Bikes: 2016 Soma Rush, Swobo Accomplice

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 60 Post(s)
Originally Posted by vailskier3 View Post
gotcha, it didn't even occur to me that the crankset would matter with the BB. Is it safe to go a couple milimeters wider?
Well, every mm you deviate from that recommendation will theoretically move your chainline farther from being perfectly straight. That said, a deviation of 2-3mm probably wouldn't be that big a of a deal.
j_e_r_e_m_y is offline  
Reply With Quote
Old 10-13-18, 05:46 AM
  #27  
vailskier3
Member
 
Join Date: Sep 2018
Location: St. Petersburg, FL
Posts: 28

Bikes: 2011 GT Series 2 SRAM Apex, 1980's Bianchi Rekord 841

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Ok, so I just measured my bottom bracket shell and it looks like its 70mm. That means it is italian thread, correct?
vailskier3 is offline  
Reply With Quote
Old 10-14-18, 09:00 AM
  #28  
seamuis
aire díthrub
 
seamuis's Avatar
 
Join Date: Sep 2017
Location: chatham
Posts: 364

Bikes: Raleigh Competition, Pashley Roadster Sovereign, Cielo Sportif Classic, Mercian Vincitore Speciale

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 165 Post(s)
Originally Posted by vailskier3 View Post
Ok, so I just measured my bottom bracket shell and it looks like its 70mm. That means it is italian thread, correct?
typically yes, if the shell is 70mm it’s ITL threaded.
seamuis is offline  
Reply With Quote
Old 10-14-18, 04:24 PM
  #29  
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Posts: 19,859

Bikes: Several, mostly not name brands.

Mentioned: 87 Post(s)
Tagged: 0 Thread(s)
Quoted: 1478 Post(s)
Originally Posted by vailskier3 View Post
Ok, so I just measured my bottom bracket shell and it looks like its 70mm. That means it is italian thread, correct?
Not necessarily. Shell width is only loosely correlated with thread spec. While many Italian road bikes have 70mm wide shells and Italian thread, some Japanese road bikes from the 70s and early 80s have 70mm wide shells and English thread. And some Italian track bikes from the 60s and 70s have 65mm wide shells and Italian thread. And some frames start out with 68mm shells and English thread, then get cross-theaded and stripped so an English thread bottom bracket is not secure, so the frame gets reamed and re-tapped to Italian thread.

The only way to be sure what thread your bottom bracket shell uses is to check it directly. If it's Italian thread, a known English thread cup will fall into the shell without engaging any threads.
JohnDThompson is offline  
Reply With Quote
Old 10-15-18, 05:20 AM
  #30  
vailskier3
Member
 
Join Date: Sep 2018
Location: St. Petersburg, FL
Posts: 28

Bikes: 2011 GT Series 2 SRAM Apex, 1980's Bianchi Rekord 841

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Thanks for the info guys. I ordered an italian thread BB, so I guess we will see if it works!
vailskier3 is offline  
Reply With Quote
Old 10-16-18, 09:49 AM
  #31  
vailskier3
Member
 
Join Date: Sep 2018
Location: St. Petersburg, FL
Posts: 28

Bikes: 2011 GT Series 2 SRAM Apex, 1980's Bianchi Rekord 841

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Originally Posted by j_e_r_e_m_y View Post
Well, every mm you deviate from that recommendation will theoretically move your chainline farther from being perfectly straight. That said, a deviation of 2-3mm probably wouldn't be that big a of a deal.
also, couldn't you just add spacers to the hub to correct the chainline? So my thought was it would be better to go a few mm wider and just add spacers if needed...
vailskier3 is offline  
Reply With Quote
Old 10-16-18, 09:51 AM
  #32  
j_e_r_e_m_y
Minor Annoyance
 
j_e_r_e_m_y's Avatar
 
Join Date: May 2015
Location: Milwaukee
Posts: 199

Bikes: 2016 Soma Rush, Swobo Accomplice

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 60 Post(s)
Originally Posted by vailskier3 View Post
also, couldn't you just add spacers to the hub to correct the chainline? So my thought was it would be better to go a few mm wider and just add spacers if needed...
No, because spacers sit outside of where the cog or freewheel threads on. You'd essentially make the axle wider, necessitating wider dropouts, without changing the position of the cog/freewheel or the overall chain line.
j_e_r_e_m_y is offline  
Reply With Quote
Old 01-07-19, 12:19 PM
  #33  
vailskier3
Member
 
Join Date: Sep 2018
Location: St. Petersburg, FL
Posts: 28

Bikes: 2011 GT Series 2 SRAM Apex, 1980's Bianchi Rekord 841

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Is that true? You can only add spacers after the cog? Is there no way to move the cog out? Am I better off buying wheels and having a shop dish them to correct the chainline?
vailskier3 is offline  
Reply With Quote
Old 01-07-19, 07:57 PM
  #34  
seamuis
aire díthrub
 
seamuis's Avatar
 
Join Date: Sep 2017
Location: chatham
Posts: 364

Bikes: Raleigh Competition, Pashley Roadster Sovereign, Cielo Sportif Classic, Mercian Vincitore Speciale

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 165 Post(s)
Originally Posted by vailskier3 View Post
Is that true? You can only add spacers after the cog? Is there no way to move the cog out? Am I better off buying wheels and having a shop dish them to correct the chainline?
i think there might be a misunderstanding here. Yes you can move a sprocket out (toward the drive side) by putting spacers to the inside of the sprocket, to adjust your rear chainline outward. Spacing the sprocket is different from dishing a wheel, which involves moving the axle alignment and adjusting the spoke tensions (and possibly needing to modify the spoke lengths on one side of the wheel, which can necessitate replacing spokes). If you want to adjust axle alignment on a multispeed wheel, the wheel will then require redishing. If you simply want your sprocket further outboard, all you need is spacers. Of course, you only have a very limited amount of threading to utilise for spacers, so the amount of outboard adjustment you can achieve is rather limited.

if you buy a new set of wheels that are ‘track’ wheels, they will already have a centered axle and will require no dishing. If you can’t achieve a good chainline by moving the sprocket outboard a few multimeters, then you need to move your chainring or entire crankset inboard.

Last edited by seamuis; 01-07-19 at 08:02 PM.
seamuis is offline  
Reply With Quote

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