First fixie build
10-11-18 | 07:08 AM
#26
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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.
10-13-18 | 05:46 AM
#27
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From: St. Petersburg, FL
Bikes: 2011 GT Series 2 SRAM Apex, 1980's Bianchi Rekord 841, 1954 Schwinn Twinn
Ok, so I just measured my bottom bracket shell and it looks like its 70mm. That means it is italian thread, correct?
10-14-18 | 09:00 AM
#28
aire díthrub
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From: chatham-savannah
Bikes: Raleigh Competition, Pashley Roadster Sovereign, Mercian Vincitore Speciale
10-14-18 | 04:24 PM
#29
Old fart
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From: Appleton WI
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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.
10-16-18 | 09:49 AM
#31
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From: St. Petersburg, FL
Bikes: 2011 GT Series 2 SRAM Apex, 1980's Bianchi Rekord 841, 1954 Schwinn Twinn
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...
10-16-18 | 09:51 AM
#32
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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.
01-07-19 | 12:19 PM
#33
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From: St. Petersburg, FL
Bikes: 2011 GT Series 2 SRAM Apex, 1980's Bianchi Rekord 841, 1954 Schwinn Twinn
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?
01-07-19 | 07:57 PM
#34
aire díthrub
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From: chatham-savannah
Bikes: Raleigh Competition, Pashley Roadster Sovereign, Mercian Vincitore Speciale
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.
03-25-19 | 12:22 PM
#35
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From: St. Petersburg, FL
Bikes: 2011 GT Series 2 SRAM Apex, 1980's Bianchi Rekord 841, 1954 Schwinn Twinn
thanks for clarifying. sorry it took so long for me to get back on here. been busy working on the old house. starting to look at wheelsets now. i think i'll be good to just get a track wheelset and space the cog out a bit.
03-25-19 | 01:25 PM
#36
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Umm, you're not going to be able to space out the cog very much on a track wheelset. Why are you committed to using a crank and bottom bracket that give you the wrong chainline?
03-25-19 | 01:27 PM
#37
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From: St. Petersburg, FL
Bikes: 2011 GT Series 2 SRAM Apex, 1980's Bianchi Rekord 841, 1954 Schwinn Twinn
i'm not, just never done this before and i'm having a hard time understanding the mechanisms involved. i guess i need more learning.
03-25-19 | 01:32 PM
#38
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Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers), All-City Space Horse (hers)
03-25-19 | 01:35 PM
#39
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From: St. Petersburg, FL
Bikes: 2011 GT Series 2 SRAM Apex, 1980's Bianchi Rekord 841, 1954 Schwinn Twinn
Yes, it was italian. I got a Shimano Bottom Bracket BB-UN55, Square Taper 70x110mm and paired it with a ofmega crank and 46T chainring.
03-25-19 | 02:01 PM
#40
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03-25-19 | 02:43 PM
#41
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From: Portland, OR
Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder
For my Peter Mooney fix gear project, I built up a wheel around a double sided track hub, spacing it from 120 to 126 with 4mm of dish. Had made for me a double cog "dingle" that I screwed onto the dished in side. Made up a triple crankset. Now I had a wheel with 3 cogs, each one lining up with one specific chainring, giving me three very different gears with the rear wheel moving in the dropout very little. This wheel rides rock solidly in all three gears. Yes, a true bastard, but a very happy one.
Ben
03-26-19 | 05:58 AM
#42
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From: St. Petersburg, FL
Bikes: 2011 GT Series 2 SRAM Apex, 1980's Bianchi Rekord 841, 1954 Schwinn Twinn
03-26-19 | 07:50 AM
#43
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Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers), All-City Space Horse (hers)
https://sheldonbrown.com/chainline.html
Last edited by ThermionicScott; 03-26-19 at 08:02 AM.
03-26-19 | 09:29 AM
#44
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From: St. Petersburg, FL
Bikes: 2011 GT Series 2 SRAM Apex, 1980's Bianchi Rekord 841, 1954 Schwinn Twinn
i'll have to measure that when i get home from work. thanks for the info! i'm guessing i'll need this info before i purchase my wheelset.
03-26-19 | 09:34 AM
#45
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Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers), All-City Space Horse (hers)
03-26-19 | 09:45 AM
#46
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From: St. Petersburg, FL
Bikes: 2011 GT Series 2 SRAM Apex, 1980's Bianchi Rekord 841, 1954 Schwinn Twinn
good to know. i am also realizing that most hubs are around 120mm, and my rear dropout spacing is 126mm. i guess i may have to do something different, but i don't know what that is yet, lol.
03-26-19 | 10:17 AM
#48
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Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers), All-City Space Horse (hers)
^ This. My FG conversion is the same way, it has 126mm dropout spacing. I added a 3mm spacer behind each locknut. 
03-26-19 | 03:05 PM
#49
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From: St. Petersburg, FL
Bikes: 2011 GT Series 2 SRAM Apex, 1980's Bianchi Rekord 841, 1954 Schwinn Twinn
03-26-19 | 03:23 PM
#50
aire díthrub
Joined: Sep 2017
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From: chatham-savannah
Bikes: Raleigh Competition, Pashley Roadster Sovereign, Mercian Vincitore Speciale
you wouldn’t actually need to do anything if you use a 120mm hub. I have a 126 conversion and it takes literally no extra effort to simply hand tighten the nuts down and take in the 3mm per side. I mean, there’s nothing wrong with dropping some cash on a couple of spacers, but it’s completely unnecessary.