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 bought a set of Aluminum with Ball Bearing Pulleys for my early 80's Peugeot. But before I could receive them, my Wife's 1970 Gitane pulleys broke/crumbled on a ride.. Both Gitane & Peugeot use similar Simplex systems.
They were the ONLY 10 Tooth 6MM pulleys I could find.
When I got them this past weekend, I put them on the Gitane, but found the shim type pulleys were 10.5MM thick, and the aluminum BB pulleys were 6.5MM wide. Chain rubs against side mounts. I found M6 Stainless Steel washers, and put one on each side of new pulleys.. Chain clears the s... Read more >>
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I made several mistakes, and I would love any and all assistance:
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OK, so a while ago I noticed to get into the lowest gear (largest sprocket) on the rear I had to apply extra pressure onto the shift-lever.
Now my bike does not even get past fourth gear, this is whilst it is on supposed 1st gear (on the shifter). At the moment it only has a range of 3 available sprockets to use. Also, on the gear shifter, it only goes from 1, to 2, then only just onto 3 (it feels extremely weak, rather than 'clicking' like the front gear shifter does), the rear shifter is not able to go into 4.
I decided to open up the rear shifter and see if there was anything w... Read more >>
Hi, whenever I've got a 6 speed mountain bike, but whenever I switch into the lowest gear, the chain slips off of the freewheel into the frame and is a paint to pull out again. When I put the bike up into the stand, it switches to lowest gear fine without coming off at all. It seems the pressure of my feet on the pedals makes it slip off. Just wondered if you had any suggestions? thanks.... Read more >>
I am trying to upgrade my 50/34T 105 chainset to an Ultegra 6800 46/36T system with all the appropriate 6800 components
Unfortunately there is not enough adjustment on the braze on front derailleur to enable me to achieve the recommended 1 - 3mm gap between the top of the big ring teeth and the bottom of the derailleur. The closest I can get is 4.5mm due to the smaller diameter of the 46t chainring.
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My son Supercycle 1800 has Falcon FIS 6 speed thumb shifter, which is stuck in 2nd gear and its lever is also broken.
I would like to replace it but could not find anything which worth cost, especially which is with in my rice range ( as the bike itself is not expensive)... Most of the time cost goes up because of shipping cost to Ontario, Canada.
I was wondering if someone could tell me what is compatible with Falcon Derailleurs? As that will help me pick alternates for thumb shifter..
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i thought messing a bit with the limit screws would solve it but i think i have over done it and made it worse.
what should i do?... Read more >>
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Now that that's out of the way,
I have a problem locating a part for my down tube shifter. It's a flat washer that has a small hook or tab on it that sits inside the shifter. The hook part has a crack and is starting to break off. Does anyone know where I can get a replacement part for it?
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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 >>