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 got a Shimano tourney front derailleur on my bike. Need to replace it. How to get the chain out?. I hope, I do not have to break a link on the chain. I see a rivet in one end of the metal. I do not see screw or bolt tightening the two ends.... Read more >>
I followed the instructions in this video
but I still have the same problem on a Shimano Sora race bike.
With the front derailleur, when I want to switch down from a larger clog to a smaller one, I always have to press the shifter twice: the first time moves the derailleur just a little bit and the second time does the job.
Any hint?... Read more >>
I have an old 1984 Miyata Model 100
and I plan on replacing the drop handlebar with straight bar.
I'd also like to replace the old lever shifters with thumb shifters on the handlebar. I'm sure this has been done a thousand times but I couldn't find any instructions in this forum.
Any help is appreciated.
... Read more >>
I have one of these old STI shifters from the early 90's
I can shift between the center and small chainwheels, but not from the center up to the big one.
The button goes all the way without resistance.
Any way to fix this or is is screwed for good?
Thanks in advance!... Read more >>
new to the site; I'm sure this is something that has come up before, but I'm currently trying to do a single-speed to 8x geared conversion, with a downtube shifter.
I've got the dropdown hanger for the rear derailleur bolted into the drop-out (after reading advice from this site...thanks!), and the rear derailleur mounted.
The chain runs through the derailleur and smallest gear (and the front cassette) fine, and I've attached the cable into the derailleur OK. The derailleur adjusts position when I use the shifter, but the chain doesn't move with it. I can manual... Read more >>
Morning! The shift paddle on my Campagnolo Centaur 10-speed left-side/front lever broke yesterday on my road/commuter bike. Needless to say, I'm pretty upset with myself, and I'd like to get the bike back on the road ASAP with as little cost as possible. To that end, a few questions:
1. Can I replace it with any Campy 10-speed lever? eBay has some Centaurs, but there are a few sets of Chorus levers that are offered at lower prices.
2. Is it worth trying to get repaired?
3. Are there other options I should consider?
Thanks a ton!
... Read more >>
I have a Giant Cypress DX purchased in Sep. 2015. I am relatively new to bicycling, just started about 2 years ago. I now little, if anything, about bicycles.
I recently removed the rear wheel while cleaning the chain and rear cassette. It was in 3rd gear when I removed the wheel. When I put the wheel back on I put the chain on the 5th gear instead of the 3rd gear on the cassette(counted in the wrong direction). I rode the bike and it immediately jumped to 5th gear on the shifter, which is where the chain actually was. Since then when shifting from 4th to 5th gear it usual... Read more >>
I am having some issues with a SRAM Apex rear shifter and the rear derailleur. I have pulled the shift cable tight and through the holding bolt of the rear derailleur and the barrel adjuster is turned all the way in clockwise. Shifting to easier gears works well, but shifting to the harder gears does not. The shifter clicks but the cable does not stay seated in the spool and remains slack when shifting to harder gears from easier gears ( see picture).
Read more >>
Hi I need some help my grandson has messed with the derailleur on his bike it no longer works and you can only get the pedal to turn a little bit and it jams and wont turn I don't know any think about bikes so I need help to try and fix it for him... Read more >>
Just bought a used MTB with several XT components and some lower quality ones.
I can't figure out the model of the rear derailleur
It's Shimano, but I don't know which one
Has anyone an idea?
Thanks... Read more >>
I've a 9speed DA that is fine going up & down the gearing, but put a load on 1st, 2nd & sometime, the chain skips. I cannot get my indexing right to get rid of it, any thoughts?... Read more >>
I inherited a bike with an Eddy Merckx frame about a year ago. The bike has some Campagnolo components, including rear shifters which have an issue. I'd rather repair the shifter than replace it because the bike as some sentimental value, and the longer I can go without replacing parts the better.
The thumb shifter usually locks when I try to shift, but if I hold the brake lever over to the right with my index finger the thumb shifter functions again. My mechanic told me that a spring in the shifter needs to be replaced and that it can be hard to identify a compatible sprin... Read more >>
I have a Shimano Deore SL-M570 shifter (circa '00) that has a lot of up and down play in the thumb lever for the front derailer. Unless I press the thumb lever upward toward the body of the shifter, the loose condition causes it to miss the pawl to shift from the second to the third chain ring. If I open up the bottom cover on the shifter, it would appear that it can be tightened by the hex bolt that is visible, but there is a small metal plate underneath it, with two tabs that stick up on two sides of the bolt, apparently preventing it from turning ( Read more >>
Let's start off by saying I'm not mechanically inclined but like to fix on my own when able. I have, I'm guessing, a 15-20 year old 15 (3x5) speed Magna Outreach and the right 5 speed grip shifter (SRAM MRX 170-51) is broken internally and apparently 5 speed shifters are rare nowadays. My question is, will any shifter do or does it have to be compatible with the rear derailleur? I currently have a Shimano SIS rear derailleur. The reason I ask is, the old shifter has gear 1 almost 180 degrees away from gear 5. On the only 5 speed SRAM grip shifter I can find on the internet (SRAM MRX Comp), ... Read more >>
HI Guys,.. Got a real nice Trek 7.4 from craigslist the other day and the bike does ride like a dream... at least from what I'm used to (Wal-mart!)... But it does seem to have a gremlin that I can't figure out. The chain will randomly come off the front gear set to the inside. I've checked the inner limit setting and it's set so that there's just barely any clearance between the chain and the derailleur when both front and back gears are set to the lowest gear. It won't do it everytime,.. I don't see how it's even coming off, but it's happened 3 times in 2 days and it's driving me nuts... Read more >>