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

Chainring replacement oh no!

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.

Chainring replacement oh no!

Old 05-27-19, 08:38 PM
  #1  
themp
Senior Member
Thread Starter
 
Join Date: Aug 2015
Posts: 235

Bikes: Specialized Crosstrail

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 79 Post(s)
Liked 30 Times in 22 Posts
Chainring replacement oh no!

Just replaced the cassette and chain on my Specialized Crosstrail Elite Hybrid 2016 and ended up with a set of noisy chain rings under load. Here is the symptom as stated on another thread.


Help: Why is my small chainring so noisy?


So I went to my local LBS to get a Small 64 BCD 32T chain ring and a Large 104 BCD 44T chain ring. I put them both on and found out that the large chain ring hits the chainstay after tightening down on the bottom bracket taper. The crank is a Samox 2X10 44/32. Here is a link to the large chain ring:


https://www.amazon.com/Truvativ-Chai.../dp/B006M4KG52


The only response from the LBS is to keep the large chain ring I have and just replace the small one. That does work. But I really would like a new large chain ring. The problem is tied to the original chainring that has a 4 MM offset to the outside while the new large chain ring is flat. Here is a link to a set of pictures with the old large and new small chainring installed, with the new large beside it. As you can see this offset of 4 MM is what I need in a new large chain ring. LBS was really not interested in going any further. I have replaced everything on the drive train except the large chain ring. Any ideas on how to solve this? New crank? Searching on line is quite difficult just by looking at the pictures for chain rings.


https://www.dropbox.com/sh/0qsokotn8...6M0lsTWBa?dl=0
themp is offline  
Old 05-28-19, 06:30 AM
  #2  
zacster
Senior Member
 
Join Date: Jul 2004
Location: Brooklyn NY
Posts: 7,190

Bikes: Kuota Kredo/Chorus, Trek 7000 commuter, Trek 8000 MTB and a few others

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Liked 260 Times in 209 Posts
Try to find an identical replacement. If they are made as OEM equipment for your bike, there are undoubtably replacements available.
zacster is offline  
Old 05-28-19, 06:47 AM
  #3  
Trevtassie
Senior Member
 
Join Date: Jun 2015
Location: Down Under
Posts: 1,929

Bikes: A steel framed 26" off road tourer from a manufacturer who thinks they are cool. Giant Anthem. Trek 720 Multiroad pub bike. 10 kids bikes all under 20". Assorted waifs and unfinished projects.

Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1046 Post(s)
Liked 949 Times in 532 Posts
Longer bolts and spacers
Trevtassie is offline  
Old 05-28-19, 07:12 AM
  #4  
themp
Senior Member
Thread Starter
 
Join Date: Aug 2015
Posts: 235

Bikes: Specialized Crosstrail

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 79 Post(s)
Liked 30 Times in 22 Posts
Originally Posted by Trevtassie View Post
Longer bolts and spacers
When using the large chain ring I had to use spacers on the small chain ring(4 MM) to get it in correct position since the large chain ring is 4 MM closer to the frame. I would have to mill the crank on it's spider connectors to move the large chain ring out.
themp is offline  
Old 05-28-19, 01:31 PM
  #5  
63rickert
Senior Member
 
Join Date: Dec 2013
Posts: 1,835
Mentioned: 43 Post(s)
Tagged: 0 Thread(s)
Quoted: 936 Post(s)
Liked 250 Times in 185 Posts
What you just discovered is there are no longer any standards in bike parts. Stronglight 49d crank was shown in 1932, fully marketed in 1934 and manufactured with no changes for almost 50 years. There are currently several copies of that crank being sold still (Sun XCD, Velo Orange, maybe more) and you can get chainrings easily. In fact you can use steel chainrings made before 1932. When marketers want to introduce new and unique configurations every day of the week lots of orphan parts happen. Try not to buy that kind of junk. Often you won't know in advance you have an oddball part, in many market segments you don't even have a choice to buy standard parts.

LBS could spend a lot of time and get nowhere on this one. They see it every day and usually have no good choices. Parts distribution is a train wreck. You could try to contact Specialized yourself. I'd not even know where to look to find if Samox is a real company or a name used once.
63rickert is offline  
Old 05-28-19, 01:50 PM
  #6  
headasunder
Senior Member
 
Join Date: Jul 2015
Posts: 325
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 69 Post(s)
Liked 11 Times in 8 Posts
the spacers would go on the big ring side but if you need to shift it 4mm to miss the chain-stay then that is too big a jump between the rings, was the original 32 tooth ring scalloped to match the big ring? I would look at how much the crank needs to shift and then consider whether a longer bb would still allow a reasonable chainline and front dérailleur adjustment. Option 2 and 3 would be a smaller big ring or look at new crank and bb options I prefer the outboard bearing type like the hollowtec 2 varieties.
headasunder is offline  
Old 05-28-19, 02:41 PM
  #7  
79pmooney
A Roadie Forever
 
79pmooney's Avatar
 
Join Date: Oct 2014
Location: Portland, OR
Posts: 9,665

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

Mentioned: 103 Post(s)
Tagged: 0 Thread(s)
Quoted: 2989 Post(s)
Liked 1,583 Times in 1,050 Posts
4 mm difference between the old and new chiainrings? That sounds really high. Did you take the crank off to change them? Tighten the crank tighter than it was before when you put it back on?

Now the deed is done. You can add a spacer inside the fixed cup and move the whole BB out a bit. A few of us have brought life back to overly forced crank tapers using sheet aluminum (often from soda cans) between the spindle flats and the crank flats. There was a thread recently on doing this. Another option is a new BB with a longer spindle.

If you space out the outer ring; two cautions. You could have such a large gap between the chainrings that the chain falls into it and gets stuck. The end result could be bad. Also you want to make sure that the nut side of the chainring bolts has a sleeve long enough to project into the chainring. It is that sleeve that supports the chainring, not tension from the bolt. If the sleeve isn't long enough, the chairing will slip, the bolt and sleeve will elongate the holes in the spider and chainrings and you will end up needing to replace the crankset. (Not dangerous. Just expensive.)
79pmooney is offline  
Old 05-28-19, 07:18 PM
  #8  
themp
Senior Member
Thread Starter
 
Join Date: Aug 2015
Posts: 235

Bikes: Specialized Crosstrail

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 79 Post(s)
Liked 30 Times in 22 Posts
Originally Posted by headasunder View Post
the spacers would go on the big ring side but if you need to shift it 4mm to miss the chain-stay then that is too big a jump between the rings, was the original 32 tooth ring scalloped to match the big ring? I would look at how much the crank needs to shift and then consider whether a longer bb would still allow a reasonable chainline and front dérailleur adjustment. Option 2 and 3 would be a smaller big ring or look at new crank and bb options I prefer the outboard bearing type like the hollowtec 2 varieties.
Went to a different LBS today and showed them my crank and the two large chain rings. Had the chain bolts off so they could see the setup with the new large chain ring and the old. The conclusion was to move to a new BB like the Hollowtec and dump the BB taper. So, tonight I put it back together with the old large and new small chain ring and all is back to normal shifting. The new small chain ring is quiet and the old large has some noise under load. Going to begin the process of moving to a new type of BB.

Thanks for all the comments!
themp is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Mike63
Utility Cycling
5
10-31-17 07:29 PM
providencebikes
Bicycle Mechanics
7
07-08-17 05:28 PM
CanadianBiker32
Bicycle Mechanics
5
11-15-15 03:49 PM
Ludkeh
Tandem Cycling
14
02-06-13 03:35 PM
cpk0
Road Cycling
14
08-07-10 07:05 PM

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 - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.