10 Common MTB Chain Maintenance Mistakes & How to Avoid Them

The chain is one of the most important parts of the bike, and it's also under constant stress from you, as well as the elements. Looking after your chain is actually very easy once you know a bit about how they work. Let me elaborate on that, and I'm going to show you some classic chain mistakes. KMC actually approached us and asked us to make this video to help people understand the types of mistakes that people make commonly with chains, and more importantly, how to avoid making those mistakes, which in the long run, it's going to make everything work a bit better, and it's going to help save you some cash. Let's have a quick look at the anatomy of a chain so you can just understand a little bit about them. Now, obviously, chains come in all sorts of different speeds, anything from a single speed up to 12-speed, which we have currently on mountain bikes. This one is a 12-speed KMC chain. Still has the same components as any other chain, but it does have a few things to point out. They have these outer plates. You notice on these outer plates, if you look very closely, they have slightly chamfered edges here. This is to enable the chain to silently, with no friction or noise, basically move around up and down the block. If you think it's got to stretch effectively sideways like this over a huge range of gears, 12 gears in fact, that enables them to do it so silently and efficiently, and also to hop up and down the cassette at the rear. Then you have this blue link here for ease of, so you can see it really, that's the inner link. You can see the outer links and the inner links. In joining them together, you have the pins, and then you have the rollers that go around the pins on the inside. The rollers actually rotate slightly. It's not something that actually people pay much attention to. This basically is where the lubricant has to get into when you're lubing a chain. Absolutely vital. If the lube doesn't penetrate into here, it's not going to be doing its job. You also get the joining link on a chain. Traditionally, you would join a chain and rejoin a chain using the pins within it. Since chain technology has hopped up, you need a dedicated link to rejoin a chain, or sometimes a dedicated pin, but it's more common to have a link like this. They have all sorts of different names. This one is a KMC one. It's called a missing link. The most important thing to underline with all of these joining links on the chains is most of them are single-use only, unless they specify they could be used multiple times. This is why you need to make sure you have some spares of these. Carrying a spare means you will be able to get out of mischief on a trail when you do break a chain, which seldomly happens, but it's always going to happen at the most annoying time and somewhere that's the furthest from home possible. Fundamentally, all chains from nine-speed, which is nine gears at the rear, to 12-speed, with 12 gears at the rear, are all 2.18 millimeters as an internal measurement. The distance it changes is the external measurement. The more gears you have, the narrower the chain has to get in order to retain the flex and enable it to have the room to actually pass between the gears. For this reason, it's absolutely vital to have the correct speed chain for the amount of gears you have on your bike, or you just won't be able to get those gears, or they just won't work very well. Make sure you're up to speed on that. You might have heard of something called chain pitch. This is referring to the length of a chain. Now, you look on all modern mountain bike chains, and it's a half-inch pitch, and that's measured from pin to pin, or one complete link. In millimeters, that's 12.7 millimeters. Yes, I know there's some of you out there watching that do not maintain your transmissions. If you work in a bike shop, you most definitely will have seen a customer come in at some point with what looks like tar painted on. Maybe they've used some three-in-one oil or any old stuff. They've just kept on pouring on their transmission and kept on riding in foul conditions. Don't do this. Everything is going to be sticky. Nothing is going to work very well, and you're actually making things worse for yourself because you're going to just prematurely wear everything out. Think what a transmission is. It's built up of external components on a bike. They're reliant on being clean and lubricated to work. If you're not allowing them to be clean and lubricated, you're just wearing them out with nature's finest grinding paste. Not checking your chain wear. This is something that I think the vast amount of riders out there are guilty of, and it's probably just because of the lack of education in why it's important. Almost certainly, you will have heard of a term called chain stretch. No. Right. You're not actually going to stretch these metal links. That's not what happens. What happens in chain stretch is the actual pitch of the chain changes. Just to remind you, the pitch is measured between those two pins. How can that possibly get longer? The chain doesn't stretch, right? What happens is these internal components, the rollers, they wear out from the inside. They get baggy, essentially. The chain's going to get wobbly, and that pitch changes. When that pitch changes, you'll find that the chain that was perfectly designed to harmoniously work on your chain rings, the pulley wheels, and the sprockets at the rear will suddenly start be wearing on different parts of the rest of your transmission, and it's going to wear everything out at an increased rate. This is why it's so important to check your chain for wear. Now, there's various different factors that can wear your chain out more, and the number one is not looking after your chain, not maintaining it. You think if you're going to get sandy, gritty mud on the inside of these rollers, which can happen, you're just prematurely just wearing it down. Keep an eye on your chain by getting one of these little fellas. This is a chain checker. They are dirt cheap, and they're very simple to use. Simply line it up in the chain, and then using the measuring gauge built onto one end here, it will directly tell you printed on it when it's good or bad. Anything under 0.8 is good. Anything over 0.8, very bad. Our recommendation here at GMBN Tech is to actually replace the chain before it's worn. Now, it's up to you how early you want to do this, but the sooner you do this, the more life out the rest of your transmission you're going to get, and ultimately, it's going to save you money. Now, it's not uncommon to be able to get two chains to one transmission, but if you're really hot on this, you could get three chains out one transmission. When you consider the price of a chain versus an expensive 12-speed cassette, it's kind of a no-brainer. Now, of course, this is a great tool, and we do recommend that everyone have one. Bear in mind, it doesn't cost a lot of money, and it will definitely save you money over the years, but it's not exactly glamorous as far as tools go. If you're the sort of person like me that really loves their tools, there's only one way to go about it, and that is to get yourself one of these bad boys. Now, this is a digital chain checker, and it is the most accurate thing. It's actually ridiculous as far as tools go if you consider the amount of use it gets compared to other things like your Allen keys, but how cool is that? Some people, before even putting a chain near their bike, seem to soak their chains in degreaser to clean away the grease that's put in them at the factory in order to start fresh. Now, it seems I'm not the only one that recommends not degreasing a chain from new like this. KMC actually says that you should never degrease one of their chains by putting it in degreaser because of the fact that the grease that's injected in there at the factory is so hard or nearly impossible to replace. Of course, no grease on the inside of the chain just means it's going to wear out quicker as the grit and the grime can get in there and wear out those rollers, changing the pitch of your chain. Now, of course, there will be some residue on the chain as new. You have a lot of packing grease around the chain. Now, some people choose to wipe this off to start with. You could do that if you want, but actually, it's already on there. You may as well get your first ride underway and then get on with it. As far as cleaning that residue off goes, the best way to do that would be to simply pass the chain through a bit of degreased rag just like this, and then literally just wipe it clean from the chain. Next up is not using your joining links correctly. For whatever method, there's a bunch of things that you can do wrong quite easily, and there's a bunch of tricks that can make it easier for yourself. First up, all you really need to do is hold the chain taut, put the master links together, and they clip shut, but that in itself poses a few problems. If you're fighting the tension and you're trying to hold this together and put the link in at the same time, it can be a bit tricky. It's possible to hold the chain tight enough like that and do it, but again, it makes it hard. The first option is by making one of these. I've actually made this from an old spoke, cut it down, and bent it with a pair of pliers. This acts as a third hand, super useful because you can literally clip the chain together, giving yourself a bit of slack to play with there, meaning it acts as a third hand, enabling you with your joining link to literally clip the chain together. Then you can remove the third hand tool and then snap it shut. However, there's also some very cool products available, like this one. It doubles up as a few different things. Firstly, you've got the slots in here to hold the chain in the same manner, which I'll show you. Secondly, you can actually store an additional link on the tool, and thirdly, it's a tire lever. That's the sort of thing you should be carrying with you when you go riding anyway. Brilliant piece of kit, so simple to use. I'm just going to show you how to use it, and then we're going to get the most out of actually joining the chain together. Before I actually go any further, I should point out, if your bike has a clutch derailleur on it, which it probably does, if it's a Shimano one, make sure you've turned the clutch off so you're not fighting it. If it's a SRAM derailleur, it will have a cage lock on there. There's a little button at the back. You can pull the cage down and lock the button in place, and it keeps the cage there. What you're looking to do is to make sure there's as minimal tension on the bottom part of the chain as possible, and that increases the chances of doing this successfully. I've already done this with the clutch, and I'm actually going to use this third-hand tool. I've got the third-hand tool just holding the chain in place, which means I'm now able to easily connect it using my joining link, or the missing link in this case. Something important to say is just to make sure on some of these, the orientation has to be correct. They're slightly different. This one isn't. I think this one's okay to put it straight on, but you need to make sure that when you put the joining link on, it sits neatly into the holes there in the slack position like that. Then, you're going to be using chain tension to click it into place. Once it's clicked into place, that's it. Your chain is permanently joined at this point. It's just important to make sure you've got everything right and you've got your chain length correct at this point. We've obviously got our missing link here ready to join the chain permanently, but something to emphasize here is when the chain is on the underside of the chainstay, it's not under tension. When the chain is on the top of the chainstay, it's under tension. When you're pedaling, that is where the tension is. We're going to use that natural tension in the chain to snap that link shut. What I want you to do is slowly rotate the pedals backwards, and you have to be careful here because of the fact that the pitch is effectively a bit different because that link isn't joined. You might find the chain doesn't line up on the chainring. I'm just going to very slowly pedal it back until the link is at the top, and then we're going to snap it. As you can watch here, there's a good chance it's going to get a little bit messed up on the chainring, as you can see. Very slowly, and then it'll click back in here. There we go. This is the joining link right here. The best way to do this is by having a back brake on or by getting a friend to hold the back wheel so it can't move. Then you want to put pressure on the crank as if you're pedaling. You'll see it just go click into place. Then always double-check that both sides have seated correctly before you ride the bike because if they're not snapped into place, the link could come apart. Of course, that's no good. From time to time, you're going to need to split your chain or remove some of the chain links. They could be out on the trail. Perhaps you've snapped your chain or you've damaged the link, in which case you will need a chain breaker. This is a tiny little compact one. Something like that is a good investment to take with you in your riding pack anyway. When it comes to splitting these joining chain links, then you really need something like this. This is a pair of pliers especially for splitting it in part. You're literally going between the two links and you squash them back together. Of course, I shouldn't need to say this again, you shouldn't be reusing these afterwards. However, these are great for the home mechanic that wants to work on stuff but you don't really want to be carrying something with you out on the trails like this. The other option is actually something a bit more trail-friendly. A set of tire levers but they've actually got a splitter built into the handle. You literally cross them over and it makes a little make-do set of chain pliers. Absolutely brilliant and nice and simple. I'll show you how easy this is to split the chain link apart. You literally sit the chain link around the pliers and then when I feel like it, I literally just squash it shut. Now, I'm sure a lot of you out there won't like the convenience of using some sort of spray that's got lube in it but not all spray lubes are as you might think. Many of them, like this one, are just a water displacer. Some water displacers actually have a solvent in them. Not only can they do a bit of lubrication but actually they can break down lubes and greases that are in the chain so you can't expect them to do the job of a proper dedicated chain lube. Treat them as just that, a water displacer, if you want to use those things. As far as chain lubes go, there's various different styles out there. There's wax-based lubes, there's wet lubes, and there's dry lubes. Wax-based lubes tend to be much better if you ride in exclusively dry conditions. To be fair, with mountain biking, that doesn't really ring home for a lot of us which leaves you down to two main choices, a dry lube and a wet lube. Now, both lubricants go on wet. A wet lube is a thick viscous liquid, very thick and it will stay in place. That's the whole point of it. It's ultra water repellent but as a result, it can also attract gunk so you wouldn't want to use that in dry conditions. However, the water repellency makes it excellent in wet conditions. The dry lube, the wet bit in it, is essentially a carrier that actually evaporates. The lubricating particles are transported with this carrier into the chain where they soak in place, then everything evaporates and you're left with a dry-feeling chain. This is what you want in dry conditions because you don't want sand and things sticking to the chain that are going to wear it out. Equally, because it's not a thick liquid that's going to stay in place, if you ride in wet conditions, you're going to wash it away quite easily. Now, lubricating a chain is something, it's not hard, but something, again, people do tend to get wrong. You don't want to be lubing a chain on the top side of the links. Lube the bottom side of the links. These are the ones that actually do all the work on the transmission. Don't just lube it the second you're about to go out riding because most of it's going to come off in the first few pedal strokes. Give it a bit of time. Run around, link at a time, give it a drop on each link and leave it for 10 minutes to soak in and then any excess that's on the chain, then you can go around with a rag and just give it a wipe. Then you're good to go and hit those trails knowing that your chain is lubricated and technically, it should last that bit longer. Now, I can feel some of you smirking a bit here. Yes, I know how to clean the bike. Well, actually, do you really? Because I see people hammering their bearings on their bikes with jet washes and just the same sort of concept can prove problematic with your chains. Now, chain baths are an excellent tool, but they're only excellent if you know how to use them. If you were to put a really sandy, filthy chain straight into one of those chain bath style tools, quite often, you can actually make things a bit grittier and a bit worse. The idea of cleaning your chain is to get all of that stuff out. Give your bike a bit of a rinse down first to get the worst off, then you can start treating areas and paying a bit more attention to them. You don't want to be putting the chain straight in the chain bath when it's full of sandy, mucky stuff. Give it a quick rinse. It's also, it will save you on whatever chain cleaner you'll use because you won't be using as much of the stuff. That's got to be good, right? Now, just a little bit of personal advice here as well is jet washes are phenomenal and they get the job done so fast, but actually, it will do you good every now and then, if not all the time, to use the old school bucket and brush method. When you clean with a bucket and brush, it actually forces you to inspect your bike and to look at things for damage because you're paying so much more close attention. Your transmission is primed for that because all sorts of things can happen with chains. Those joining links, if you hit them on rocks and stuff, sometimes they have been known to split open, but the same can happen with any chain link. It could have been twisted. It could be mangled for whatever reason. If you're not checking each individual link to see if they're splayed out or it looks like it could be damaged, then you might be asking for trouble. Now, as well as being dangerous because the chain could break, it's going to be really inconvenient if your chain breaks. Now, you might have seen a tool like this before, a chain tool, also known as a chain breaker or a chain splitter. For good reason. They're designed to split the links from the chain in order to shorten the chain or perhaps to remove a damaged link at the side of a trail. Now, they're quite simple to use. It simply has a pin driver here and has a set of guide jaws that the chain sits into. Now, something that's really important to say before I show you this is if and when you're planning on using one of these tools, you drive the pin out. You may not want to drive out all the way because you could reuse that pin to push back through and rejoin the chain. However, it's vital to say that this is not a permanent fix. It's something you should be doing in an emergency situation only. Modern-day chains have chamfered edges on the pins. They're designed to be installed and they stay that way. As soon as you put them back in again, there's a chance that they're going to split and the link will come apart and the chain will break at a really inconvenient time. Maybe you're sprinting, something like that. When you're putting power down and your chain snaps, it hurts. Trust me. However, you do need to learn to be able to do this because in an emergency situation, when you don't have your missing link or your master link with you, you may well need to do this to get yourself home. Don't drive the pin out all the way. Just a case of very slowly and smoothly engaging the tool, making sure the pin is completely lined up and then there you go. You can see it starts pushing out of the backside here. There is an element of guesstimation about this of how far you're going to go. That looks about right. Do one more half turn there and remove this. Then you should be able to wiggle the chain itself and remove that link. As you can see, it protrudes very slightly on the inside. When you're fitting a chain to a bike, this is when you get one of the classic errors here in actually routing it correctly. Firstly, you want to pay attention to all of your sprockets and the actual teeth in profile on your bike. This one's got narrow wide chainring on it, so you need to make sure the chain correlates to that and the narrow wide correlates with those chain inner and outer links. Same applies to the rear sprockets or your cassettes and even on the actual pulley wheels, guide wheels, or jockey wheels, depending on which derailleur you have. Sometimes they have a narrow wide profile to them. Now, something important to say, depending if you have a SRAM or a Shimano transmission, is to actually do something that's going to make it easier for yourself. Turn the clutch off if you have a Shimano one like this one, or if you have a SRAM design, lock that cage out. That way, you're not fighting the spring when you're trying to route the chain through it. Now, also, you want to pay attention to this little metal tab here on the inside of the cage. It's really easy to pass the chain on the wrong side of it. Basically, the chain just rubs on it. You won't necessarily notice this at first. It'll make a bit more noise than it should do, but your gears will work. Something won't be quite right, you'll have additional friction, and then the chain, after a while, will hop off these jockey wheels here, and it will cause you problems. Just make sure it's routed correctly. Another classic chain mistake is not having enough of it, running your chain too short. Now, this will happen for a couple of reasons. It could happen because it wasn't the correct length to start with. You didn't measure it out correctly. Or it could have happened when perhaps you damaged your chain out on the trail, had to remove some links, which I'm trying to illustrate with this one. As you can see, there's nowhere near enough chain to get into these top two gears. Now, if you're stuck in a position like this, you absolutely must remember at which point is too much strain for the rear derailleur and the chain, because you do not want to be spending more money to replace the derailleur. Use your limit screws at the rear to adjust your derailleur, so you cannot get into those top two sprockets. Think of it as just trying to preserve what you have. Now, of course, if you've had to split links out like this to get home, then chances are you'll need to replace the chain anyway, but at least it might get you home. Now, when you're fitting a new chain to a bike, there's a few things you need to take into account. Now, chains do come in different lengths. This KMC chain was 116 links, but it's also possible with other ones on the market to get 112 or 126 links. Now, if you're not sure what yours is, you can actually obviously just measure it by taking your current chain off and measuring the actual length of it or counting the links. If you aren't sure, go for the longest option, and you can always save some spare links, keeping your riding bag for the occasion when this might happen, and you end up with a chain that's too short in the first place. Now, when measuring your chain, you do need to take into account a few things. If your bike is a hardtail or a full suspension bike, because of the fact full suspension bikes have an effect called chain growth. As a bike moves to the suspension, you use up more chain, so you do need to factor that in. Both SRAM and Shimano have different methods of calculating the length of the chain, so do consult the manufacturer's guideline when doing this, because you do not want to be ended up with a chain that is too short for your bike. Firstly, it doesn't feel very good. Secondly, you're not going to get the range of gears. Thirdly, you could break your derailleur as well as breaking the chain when it's really strained under tension like this. Just think, with this amount of tension that's on this, if this bike had a lot of chain growth because of suspension, that's just going to completely mangle that derailleur, and you'll be buying a new derailleur as well as a new chain. Not good. Well, there you go. That is about all you need to know about all the classic chain mistakes out there. Like I said, the most important thing, really, is to maintain it and keep an eye on the wear of your chain. Get yourself a chain checker. Well worth the money. Now, hopefully, the video has been useful for you. There's a load of things we've covered. Let us know if you've missed any in the comments underneath. Let us know which one you notice applies to you the most. As always, thanks for hanging around and watching our content here at GMBN Tech. See you in the next video.