Will Having Crankset Chainline Off By 2.5mm Matter Much?
09-11-18, 08:46 AM
#1
Junior Member
Thread Starter
Join Date: Aug 2009
Location: New York City
Posts: 197
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 38 Post(s)
Likes: 0
Liked 9 Times
in
7 Posts
Will Having Crankset Chainline Off By 2.5mm Matter Much?
I'm thinking about moving a Sugino triple crankset from a Surly LHT touring bike with an english bottom bracket shell (68mm width) to a road bike having an Italian bottom bracket shell (70mm width).
The LHT currently has a bottom bracket with a 113mm spindle length for a 47.5mm chainline. The road bike has a 45mm chainline. Ideally, I'd like to put a bottom bracket with a 108mm spindle length on the road bike but that can't be done because the crank arms would touch the bottom bracket shell. I can't use a 110mm BB spindle length either because of the 70mm shell width although I could do this on the LHT if I wanted to.
Will just putting a 113mm BB on the road bike and allowing the crankset chainline to be off by being 2.5mm further out actually matter that much?
The LHT currently has a bottom bracket with a 113mm spindle length for a 47.5mm chainline. The road bike has a 45mm chainline. Ideally, I'd like to put a bottom bracket with a 108mm spindle length on the road bike but that can't be done because the crank arms would touch the bottom bracket shell. I can't use a 110mm BB spindle length either because of the 70mm shell width although I could do this on the LHT if I wanted to.
Will just putting a 113mm BB on the road bike and allowing the crankset chainline to be off by being 2.5mm further out actually matter that much?
09-11-18, 08:55 AM
#2
Really Old Senior Member
Since I use the smaller cogs a lot, I actually set mine "about that much wider".
EDIT-
The main concern is you still have enough FDER "travel" in both directions to reach the largest & smallest rings without excessive chain rub.
EDIT-
The main concern is you still have enough FDER "travel" in both directions to reach the largest & smallest rings without excessive chain rub.
Last edited by Bill Kapaun; 09-11-18 at 11:06 AM.
09-11-18, 09:05 AM
#3
Banned
it matters less the longer the chain loop is..
and if you have a derailleur drive train, not at all ..
and if you have a derailleur drive train, not at all ..
09-11-18, 11:46 PM
#4
Senior Member
Give it a try; it's probably not a big deal.
09-12-18, 02:31 AM
#5
aire díthrub
Join Date: Sep 2017
Location: chatham-savannah
Posts: 553
Bikes: Raleigh Competition, Pashley Roadster Sovereign, Mercian Vincitore Speciale
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 259 Post(s)
Likes: 0
Liked 55 Times
in
35 Posts
depending on which end of the cassette you spend more time on it could actually be beneficial. However, the only way to find out if you’re going to run into any issues with your specific setup is to try it. We can’t say it will be issue free, we can only say a 2.5mm wider chainline isn’t by itself a bad thing. Cross chained outer ring and largest cog could present an issue.
Last edited by seamuis; 09-12-18 at 02:57 AM.
09-12-18, 01:04 PM
#6
Senior Member
Join Date: Oct 2013
Location: Mich
Posts: 7,354
Bikes: RSO E-tire dropper fixie brifter
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked 2,946 Times
in
1,906 Posts
shim the cassette outboard; Unless you're unable to do so?
__________________
-Oh Hey!
-Oh Hey!
