Chewed-up chainring

Workshop tales, trials and disasters.
Maintenance tips, techniques and myths.
Technical discussion, description and outright lies

Chewed-up chainring

Postby Howzat » Thu Jan 31, 2013 9:42 am

I was cleaning the bike and noticed these chewed-up teeth on the front chainring (compact 50T). Any ideas as to what might have caused this?

Image
Image
Image

The bike has only about 1000kms on it. I did have a chain break on me a couple of months back, but otherwise no unusual drivetrain incidents. The inner 34T chainring looks fine, and I spend about 50% of the time on each ring. Is it possibly just normal wear and tear?
User avatar
Howzat
 
Posts: 530
Joined: Wed Aug 15, 2012 7:08 pm
Location: Canberra

by BNA » Thu Jan 31, 2013 9:51 am

BNA
 

Re: Chewed-up chainring

Postby Jesmol » Thu Jan 31, 2013 9:51 am

Chainrings on my SRAM chainset look the same, in fact one of mine had bent slightly causing an issue when back pedalling. I suspect they're made of fairly soft material and dont really like the chain running at funny angles across them
Jesmol
 
Posts: 247
Joined: Tue Feb 07, 2012 2:48 pm

Re: Chewed-up chainring

Postby MattyK » Thu Jan 31, 2013 10:33 am

They make them like that to aid shifting.
MattyK
 
Posts: 1312
Joined: Fri Oct 01, 2010 1:07 pm
Location: Melbourne

Re: Chewed-up chainring

Postby Howzat » Thu Jan 31, 2013 10:58 am

Interesting :!: :idea: . I noticed the asymmetric pins and scalloping on the big chain ring, I have no idea how it is supposed to work.

I did find a metal shaving I removed with a file from one of the gaps between the teeth, and some other minor marks. But that those funny-looking short teeth are a design feature is good to know.

Image
User avatar
Howzat
 
Posts: 530
Joined: Wed Aug 15, 2012 7:08 pm
Location: Canberra

Re: Chewed-up chainring

Postby jacks1071 » Thu Jan 31, 2013 11:48 am

Get yourself a set of "Needle Files" from your local Bunnings or hardware store.

Image

You can tidy up the chain ring with those, only remove as much material as is necessary.

As to the cause, the same thing that broke your chain would have damaged them - most likely shifting under too much load or an excessively worn chain. If the chain only had 1000kms on it then refer to the first cause.
Our Website is: http://www.pro-liteoz.com Find us on Facebook by searching for "Pro-Lite Australia"
User avatar
jacks1071
 
Posts: 2869
Joined: Thu Aug 20, 2009 9:47 pm
Location: Mackay, QLD


Return to The Shed

Who is online

Users browsing this forum: Google [Bot]



Popular Bike Shops
Torpedo 7 Torpedo7 AU
Ground Effect Ground Effect NZ
Chain Reaction Cycles CRC UK
Wiggle Wiggle UK
Ebay Ebay AU



InTouch with BNA
“Bicycles BNA Twitter
“Bicycles BNA Facebook
“Google+ BNA Google+
“Bicycles BNA Newsletter