42. How to Check For Chain Wear

Demonstrates how to measure a worn out chain using Sheldon Brown’s ruler technique.

IMPORTANT: Nuts and bolts on your bike should always be tightened to the manufacturer's specifications.
How to Check For Chain Wear
DVD Vol. 2 DVD Volume 2
This video is available on DVD

One of the most common problems I hear about is chain skip, which is when your pedal slips forward while pedaling under pressure. This is usually either caused by a stiff chain link, worn freehub body, or by a worn chain and freewheel. In this tutorial, we'll learn how to diagnose a worn drivetrain.

Watch the stiff link tutorial first to make sure that isn't your problem. Once you've ruled out a stiff link it's time to check if your chain is actually worn. Chains will 'stretch' over time, because the pins and bushings start to wear, which causes them to start skipping. There are many tools available that measure chain wear (listed to the right of the video), but the easiest and most accurate way to check is by simply using a ruler.

Measure the Chain

With your chain still on the bike, place the ruler's '0' inch mark directly above the center of one of your chain pins. Now count 12 complete links. A complete link equals 1 inner and 1 outer. A rivet on a new chain should line up exactly with the 12 inch mark using this method.

Wear Indicators

According to Sheldon Brown, if the rivet is less than 1/16" past the mark, your chain is ok. If it's between 1/16" and 1/8" past the mark you'll likely need a new chain, but your sprockets should be ok. If it's more than 1/8" past the mark, you'll have to replace both the chain and rear sprockets.

Cassettes & Freewheels

The reason you'd have to replace the rear sprockets is because they generally wear with the chain. While the chain is 'stretching', the gap between the teeth on your sprockets also gets wider and wider. This causes the chain to ride up over the teeth and slip while pedaling under pressure. If you install a new chain on an old sprocket, you'll probably be able to see gaps of light through the teeth as shown. Here's how to replace a cassette or a freewheel.

Front Chainrings

Your front chainrings generally won't need replacing. Because of the larger diameter, the front chainrings usually take twice as long to wear. If worn they are very easy to spot, as they'll start looking like shark teeth. Here's how to replace your chainrings.

Credits

Thanks to Sheldon Brown and Cambridge Cycling Campaign for the photos!

Tags

Related Links

Discuss this topic in the Chain Forums

05/26 Derailleur locked up

EDIT: RESOLVED

Hi,

I wonder if anyone can help with an issue I'm having with my rear derailleur.

I'm not really sure how to describe this but you can see here http://tinypic.com/r/2cwogbb/8 (direct images not working...). Basically when changing gears, the mech (which has recently been professionally fitted) locked up in the stretched out position and now I can't get it back. It has happened a few times before and released itself, but no joy this time.

Sorry if this is discussed el... Read more >>

05/13 Replacing old rear derailleur

I bought a very old Mongoose mtn bike from Goodwill for commuting to/from the metro station, and would like to replace its very old Suntour 3000 alpha rear derailleur.  Is there a model of derailleur I'm likely to find that will allow me to keep the index shifting?  Or should I give up and buy any old other derailleur for continuous shifting?
Thanks!... Read more >>

05/07 What if your new rear Dérailleur

has no cable adjustment barrel?... Read more >>

04/24 Rear Derailleur Suicide Into Spokes.

[Image: bike.jpg]
http://tinyurl.com/qdrsr3z

[Image: ke2.jpg]
http://tinyurl.com/mnroxc2

My bicycle had been shifting erratically on its own.  I downshifted and immediately after downshifting a loud CLUNK jammed my tire.  This is what the damage looks like---is this ... Read more >>

04/24 what Rear Derailleur hanger do i need

i bought a raleigh mtrax ht 1.0 but the hanger from the Rear Derailleur is missing ive been in a few bike shops and they are unsure what hanger i need. i've been online and there are hundreds of different shapes and don't want to start wasting money on hangers and they don't fit so if anyone knows the type of hanger i need would be  very helpful

here is a stock pic of the bike

[Image: MTX116BK.jpg]



*UPDATE*
I have found what one... Read more >>

04/21 Removed front derailleur.

i have  Hunter Shadow from years ago, probably the 80's, not a high end bike from Hunters in California.
it has 1.25" tubing. i sent it to a bike shop a year ago because I couldn't remedy it and they did a home made type of repair. the bike would never shift into low. same after they repaired it. no difference. the derailleur is the wrong one as it had no cable stop to attached the sheath or jagwire that fed up from the bottom cable stop.. now to the chase. i removed the front derailleur and the small and large chain rings and now have a 36 tooth middle chain ring left on the same crank... Read more >>

03/31 Rear Derailleur.. I have no idea what I'm doing

Hey guys, I'm a total novice when it comes to working on bicycles and I read through a lot of posts and I watched some youtube videos but I am really confused on how to get my derailleur back on.  I was trying to get my back tire off to change the tube and some how the derailleur inadvertently "fell off".  Also, a small metal piece fell off with(I did not see any screws land anywhere), which I have no idea where it goes or what it is for.

I don't know hardly any of the biking terminology so it has made it even more difficult for me to understand what I need to do to get it back... Read more >>

03/20 Block spacer

My new 10 speed Shimano 105 block came with a skinny aluminum spacer, which was intended to fit behind the block.  Does this always need to be fitted or is it for special circumstances?  I also have new 10 speed specific wheels and the chain does clear the spokes without the spacer.  The new chain is not smooth under pressure, could taking out the spacer be a solution?   Thanks.... Read more >>

03/14 Hierarchy btw Shimano and Sram models

Dear friends, I wanna buy a bike that will provide me both road and trail usage. and it should be also economical. There are lots of level of quality between shimano accessories such as Tiagra, Xtr.. and also same thing for Sram. Could you advice me the correct hierarchy between models acc to price. And advice a bike for both road and trail usage.Thanks in advance.. http://bikebest.net/versus/... Read more >>

02/16 Frayed derailleur cable end

The metal cap at the end of my derailleur cable somehow came loose so now the cable end has unravelled into multiple strands. They are a cut hazard and look ugly. Appreciate any suggestions on how to fix.... Read more >>

02/15 Since overhaul (I'm Impressed)

It's presently 0 Degrees F, with a -16 wind chill in Chicagoland...

It's been ~3 months since the overhaul of the 2 bikes, and I've been alternating them from the repair stand (Bunji Straps hanging from ceiling joist in basement)..
When I started I figured a squirt of oil was all that was needed.  I had no idea what nice bikes I had! 
I learned about strange part sizes from Here & Internet.
I learned about parts & "Alternate Parts" procurement from LBS, Here, & Internet.
I learned about loose bearings from the first dis-assembly.. and found b... Read more >>

02/12 Deore LX Derailleurs?

I have two Deore LX derailleurs... one is a RD550 and the other is a RD565.
Which one is a better derailleur or is there a better one?? Any differences between the two other than the model number?? Both have the SGS long cage.
Trying to figure out the Shimano numbers and quality grades.
Thanks... Read more >>

02/08 SRAM X9 - Rear Derailleur Pulley - Wobbles

Hello,

I have a Boarman Hybrid Pro (2010 Model - White http://road.cc/content/review/4160-boardman-urban-pro-ltd) and the I have had a lot of repairs on it recently.

After the latest repair I noticed the chain was wobbling from left to right more than what I expected. I bought it back to the bike shop but they gave me lip service on the cause and the repair for the problem.

With further inspecition I noticed that that both rear derailleur pulleys are wobbling and are l... Read more >>

01/26 Need to replace a RD-TZ30 drlr

Hi, I need to replace and old broken RD-TZ30 drlr 7 speed.

Does anyone know if the Shimano Acera M360 7-8 Speed would be an ok replacement?

It is for an old (but much loved) Schwinn Jaguar beach cruiser.

Thanks!... Read more >>

01/02 Rear derailleur help

I took off my rear derailleur to clean my bike and i need help putting it back on. Its a shimano derailleur with the hook. And i have a diamondback mountian bike. If anyone can help it would be appreciated!! I dont remember exactly how it was attached to the frame

Thanx
Jay... Read more >>

New Thread
How to Check For Chain Wear
Repair Guide / Help Forums

Free Email Updates: