42. How to Check For Chain Wear
Demonstrates how to measure a worn out chain using Sheldon Brown’s ruler technique.
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.
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.
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.
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.
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.
I have just done a complete overhaul on my wife's mountain bike, here is a list of what I have replaced;
Shimano MF-TZ 31, 7 speed 14-34 mega range cog set.
Shimano FC-M 171, 48\38\28T Chain set.
Shimano RD-TX35 6\7 speed rear derailleur.
Shimano FD-TX51 front derailleur.
Shimano CN-HG40 Chain.
I have adjusted and indexed the rear mech. The problem I have is with the front mech, I can change from smallest to largest cogs OK but when I change from the largest it changes to the middle cog fine but will not go to the smallest cog no matter what... Read more >>
I want to convert my Raleigh Rapide from downtube shifters to STI shifters.
So I have Campagnolo 980 derailers, 6 at the back and 2 at the front.
Sanwa Road Bike. 10 Speed. Had for about 10 years. I only have one speed 5th gear. I know videos all over. I watch them and just can't get this thing correct. Thought I'd head here for help and I have a new Schwinn coming. That's pretty inexpensive also. Looks like a nice web site also.
Problem: Start with something simple. Getting from 5th to 10th. When I push the Front Derailleur by hand it snaps back. I can pull the lever on top of bike down to shift to 10th and the lever snaps back. If I put the bike in 10th the derailleur snaps back toward the bike causing the chain to go to ... Read more >>
I've recently bought a women's Schwinn Continental at a garage sale. We think it's a 1975, but we aren't sure. Anyway, I'd like to get a totally different rear (and possibly front) derailleur for it because no matter what we do, it doesn't like to switch into all of the gears. We read that the original derailleurs on the bike don't really work well with it, so we were looking at maybe a Suntour or Shimano, but we have no idea were to start or anything. Could some one give us some information that could help? Thanks in advance.... Read more >>
Hi all, I'm a bit new to the maintenance of a bike so would really appreciate any help. I have a road bike that needs a new rear derailleur fitted.
My current rear derailleur just says shimano on it but my gears are shimano sora triple deck. I've looked online for a replacement shimano sora derailleur which are all 9 speed but mine is an 8 speed. Will this cause a problem?
Also, I've seen that you need to know the total tooth capacity. Can you just confirm how you work this out?
Thanks for any help!... Read more >>
So today I ordered some new wheels for my 700c conversion. The wheels come with a 7 speed freewheel which is just what I need. However, my current cassette is 13/23 and the new one is 14/28. What adjustments will I need to make to the rear derailleur so that it will shift smoothly and accurately on the new cassette.
Jamin... Read more >>
I've encountered a very strange problem I've never had before. I have a Fischer mountain bike with shimano acera 8 gear derailer. About a week ago it suddenly developed a very strange problem, the derailer only travels part of the distance it should to give me the full gear range. Now I only get it to go to gear sprocket 2 at the low end through to sprocket 5 or 6 towards the high end.
I've tried making various forms of adjustment to the derailer, but this has only very limited effect. Has anyone here had this problem, and any ideas about how to fix it and how it... Read more >>
I'm a bike tech at dicks sporting goods in Bloomfield, MI and I'm having trouble with replacing the cables on an old 10 speed freestyle. I've only been working at this job for about 3 months now, so I don't have a ton of experience working on bikes yet, and I can't tell how to get the cable out of the shifter.
It looks like the cable should just be able to pop out of the end of the shifter (I have already removed the housing), but I can't get it to budge. Is there something else I need to do first before I can take the cable out, or is it just that this particular one is likely j... Read more >>
We just bought a hyper havoc within the last 2 months and have only ridden it a handful of times. My issue is the other night as we were riding along the chain snapped off. Looked like it broke? We just started riding again recently so we're not familiar with these new bikes at all. Do I need to buy a new chain or can this one be fixed? I snapped it back together but I just don't know if it'll last or what. Lol I apologize for my ignorance about anything mechanical lol.... Read more >>
On the weekend I crashed and managed to destroy one of my shifters. I've got an old Cannondale 105 with 105 components - double and 9 speed. I'm wondering if any other Shimano double/9 speed shifters would be compatable or do I need to try and find an old set of the 105 ST-5510?
Thanks!... Read more >>
So I took my bike out for a ride and neither of the gears seem to shift, pressing the shift bottom (sorry dont know the name for it) next to the brakes doesnt do anything, no clicks or sounds, nothing happens.
I have no clue whats wrong with it so please help me, I'll upload more pictures if needed and do any tests
here are some pictures
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At age 43 I recently have taken up cycling, it's been about 20 years. I had found a 1982 Free Spirit 10 speed, Sears brand by Murray I think, at a junk store. $15 and everything seemed to work, couldn't pass it up. I put new tires on it and was riding, wheels fairly true, all 10 gears, no squaking or squealing, decent stopping. Then the other day, the left lever snapped off. No surprise being 32 year old plastic, I remember new bikes doing that in my younger days. So my question is, what's a good source to order this part from? I'd want to go metal and replace the whole assembly, I'm gues... Read more >>
I have a Trek 7000 (93/94) still with tons of original parts on her.
A few weeks ago, the rear shifter broke, not shifting to the lighter gears, but was still shifting to the heavier ones.
When I opened it, I saw that a little spring inside it was broke.
Just like the one seen here:
I can't find this spring anywh... Read more >>
Hey folks - first off for full disclosure, I recently removed the RD from the hanger to get a look at the hanger. What I'm asking now seems to have happened after re-attaching the RD.
The bike is about a month old so I'm not considering worn out parts yet.
OK so the RD (Ultegra 6800) attaches to the hanger by one bolt. The RD pivots on that bolt. When at rest I can rotate the RD clockwise quite a bit. Just a little rotation counter clockwise. If I rotate clockwise and then let it go there is obviously a spring inside that pushes the RD back to a resting position.
Read more >>
Hi, basically I've got a problem with the front deraillieur rub on my Triban 3 road bike when in the smallest chainring on the rear and the largest chainring up front.
I've tried setting this up myself about 4 times using this guide
I just cannot seem to make the dérailleur move far enough out! I have tightened the cable as ti... Read more >>