Would you run a chainring this close to the chainstay?
02-24-23, 02:49 PM
#26
The Wheezing Geezer
Join Date: Oct 2021
Location: Española, NM
Posts: 677
Bikes: 1976 Fredo Speciale, Jamis Citizen 1, Ellis-Briggs FAVORI, Rivendell Clem Smith Jr.
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 296 Post(s)
Liked 557 Times
in
275 Posts
So far, so good, on mine:
We have clearance, Clarence!
We have clearance, Clarence!
02-24-23, 07:12 PM
#27
Senior Member
Join Date: Oct 2013
Location: Mich
Posts: 6,427
Bikes: RSO E-tire dropper fixie brifter
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked 2,317 Times
in
1,552 Posts
FWIW; I had a modern sram crankset with sram BB that had about the same gap as the OP. It "walked" just enough to grind a quarter moon into the chainstay. It didn't take much. It was a new frame too.
__________________
-Oh Hey!
-Oh Hey!
02-24-23, 10:51 PM
#28
Senior Member
Originally Posted by Troul
FWIW; I had a modern sram crankset with sram BB that had about the same gap as the OP. It "walked" just enough to grind a quarter moon into the chainstay. It didn't take much. It was a new frame too.
02-28-23, 06:23 AM
#30
Tinker-er
Join Date: Oct 2007
Location: Mid-Atlantic
Posts: 176
Bikes: 1956 Rudge Sports; 1958 Rudge Sports; 1983 Univega Alpina Uno; 1981 Miyata 610; 1973 Raleigh Twenty; 1971 Raleigh Twenty; 1992 Breezer Lightning, V4 Yuba Mundo aka "The Schlepper"
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 69 Post(s)
Liked 99 Times
in
73 Posts
You're more likely to have a crank spider arm or chainring bent enough to contact the frame, than the frame itself bending that much.
I ran my chainrings close to the stay on my old Vitus 979, which was like a springy piece of penne pasta, and the small ring never contacted the stay.
I ran my chainrings close to the stay on my old Vitus 979, which was like a springy piece of penne pasta, and the small ring never contacted the stay.
Likes For PhilFo:
02-28-23, 07:42 AM
#31
Senior Member
Join Date: Feb 2017
Location: Northern Shenandoah Valley
Posts: 4,032
Bikes: '18 Redline Zander, '14 Surly Pugsley, '97 GT Vantara, '97 Trek MultiTrack 750, '70 Peugeot UO-18 Mixte
Mentioned: 36 Post(s)
Tagged: 0 Thread(s)
Quoted: 1400 Post(s)
Liked 700 Times
in
522 Posts
mrmb if you're asking about it, I presume it's because you're concerned about the paintwork. No judgement here...I would be also. I guess I'd ask myself what the costs are in just spacing the chainring over a little bit. I think someone suggested gaining a mil or two with a crank spacer, or even a slightly longer spindle. I understand the concern about Q-factor, but I don't think your legs, knees, or body will notice an extra couple of millimeters (my fat bike has a 168mm spindle in a 100mm bottom bracket!). I think I'd personally spend the 30 bucks now (or less if you use a thin spacer) to know you won't have any problems in the future.
03-02-23, 01:52 PM
#32
Senior Member
Join Date: Nov 2014
Location: Eugene, Oregon, USA
Posts: 27,524
Mentioned: 217 Post(s)
Tagged: 0 Thread(s)
Quoted: 17501 Post(s)
Liked 4,131 Times
in
3,071 Posts
I think the gap should be fine. The biggest risk is if you drop your chain between that gap, and have to extract it.
I'm trying to remember the mechanics of a trapped chain. It may be that it always happens on the middle/outer ring, and requires a smaller ring to pull the chain through.
In that case, it won't happen with the close small ring.
Perhaps what I'm thinking about is "Chain Suck".
Again, that may be more an interaction with outer rings than something that regularly happens with the inner ring.
I'm trying to remember the mechanics of a trapped chain. It may be that it always happens on the middle/outer ring, and requires a smaller ring to pull the chain through.
In that case, it won't happen with the close small ring.
Perhaps what I'm thinking about is "Chain Suck".
Again, that may be more an interaction with outer rings than something that regularly happens with the inner ring.
Last edited by CliffordK; 03-02-23 at 01:57 PM.
03-02-23, 02:52 PM
#33
Senior Member
Originally Posted by mitchmellow62
OP: How's the chainline look?
03-12-23, 03:56 PM
#34
Newbie
Originally Posted by mrmb
Just under 2mm
Would you run this?
Would you run this?
03-12-23, 09:14 PM
#36
Full Member
Thread Starter
Originally Posted by hokiefyd
mrmb if you're asking about it, I presume it's because you're concerned about the paintwork. No judgement here...I would be also. I guess I'd ask myself what the costs are in just spacing the chainring over a little bit. I think someone suggested gaining a mil or two with a crank spacer, or even a slightly longer spindle. I understand the concern about Q-factor, but I don't think your legs, knees, or body will notice an extra couple of millimeters (my fat bike has a 168mm spindle in a 100mm bottom bracket!). I think I'd personally spend the 30 bucks now (or less if you use a thin spacer) to know you won't have any problems in the future.
03-12-23, 09:15 PM
#37
Full Member
Thread Starter
Originally Posted by icemilkcoffee
Very easy way to test. push the front wheel into a wall corner. Put all your weight on the right pedal and bounce up and down and see if anything touches. I bet nothing touches. The chain stays will pretty much flex together with the BB.
03-12-23, 09:16 PM
#38
Full Member
Thread Starter
Originally Posted by Kapusta
Count me among those having a hard time seeing the frame flexing enough to move the stay over 2mm that close to the BB.
I’ve had really tight clearances in the past (I’d guess 2mm) and never had them gouge.
I’ve had really tight clearances in the past (I’d guess 2mm) and never had them gouge.
The gap is actually UNDER 2mm. Just barely under 2mm.
03-13-23, 05:24 AM
#39
Advanced Slacker
Join Date: Feb 2017
Posts: 5,934
Bikes: Soma Fog Cutter, Surly Wednesday, Canfielld Tilt
Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 2637 Post(s)
Liked 2,367 Times
in
1,334 Posts
Originally Posted by mrmb
It's not over 2mm.
The gap is actually UNDER 2mm. Just barely under 2mm.
The gap is actually UNDER 2mm. Just barely under 2mm.
03-16-23, 08:10 PM
#41
señor miembro
Join Date: Dec 2018
Location: Pac NW
Posts: 7,324
Bikes: Old school lightweights
Mentioned: 83 Post(s)
Tagged: 0 Thread(s)
Quoted: 3145 Post(s)
Liked 4,691 Times
in
2,446 Posts
Is the chainring steel?
03-19-23, 03:29 PM
#42
Full Member
Join Date: Apr 2016
Posts: 384
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 147 Post(s)
Liked 119 Times
in
99 Posts
Originally Posted by freeranger
Looks like I'm in the minority on this one. I wouldn't run it that close and risk scratching up that good looking paint. Why risk scratching it if you don't have to?
03-19-23, 09:02 PM
#44
Full Member
Thread Starter
Originally Posted by icemilkcoffee
Very easy way to test. push the front wheel into a wall corner. Put all your weight on the right pedal and bounce up and down and see if anything touches. I bet nothing touches. The chain stays will pretty much flex together with the BB.
