Hey guys and gals, Aaron here from bikebandit.com. One of the most essential parts of a motorcycle is the chain, which delivers power from the transmission to the rear wheel on most motorcycles. But as common of a part as your chain is, it’s also one of the parts we get asked the most questions about. What type of chain to get, what size to get, and how to take care of it are just a few of the questions that we hear all the time here at BikeBandit. So to help answer all your questions, we’re gonna put together this little crash course with everything you need to know about motorcycle chains in one place.
Here’s what we’ll be going over. First, we’ll get into some chain anatomy and show you how a chain is constructed and what different types there are. Next we’ll get into chain sizing and how to make sure you’re ordering the right size chain for your bike. After that, we’ll talk about chain strength and explain how chains stretch with use. And finally, we’ll show you the proper way to take care of your chain too. Let’s go ahead and get started.
First, let’s get into a little chain anatomy. What you see here is one link from a standard motorcycle chain from our friends over at RK, completely taken apart. As you can see, the rolling elements consist of a solid pin which spins inside a hollow bushing, and together they fit inside the roller, which is what actually makes contact with the sprockets. All these parts are held together by overlapping inner and outer side plates. To spin as smoothly as possible, a chain has to be looped inside the rolling elements, between the pin and the bushing and between the bushing and the roller.
Old school roller chains are simple. There’s just these metal parts and they rely on frequent oiling to stay lubricated. But modern chains like this one from ProTaper incorporate an additional component, the rubber O-ring, which sits in between the rolling elements of the chain and the side plates. Instead of needing external lubrication, O-ring chains, also called sealed chains, have grease injected inside the rolling elements during the manufacturing process, and the O-ring is there to seal that grease in place. So that leads us to the question, if O-ring chains are internally lubricated, then why do you still have to lube them regularly? Well, what you’re doing when you lube an O-ring chain is really keeping the O-rings themselves pliable so they can maintain their seal and keep the internal grease where it needs to be. Compare this to lubing a simple roller chain, where you’re actually replenishing the lube inside the rolling elements themselves.
The vast majority of bikes these days come with sealed chains from the factory, and most of the chains you’ll find for sale, especially for street bikes, are sealed chains too. But something to look for is different varieties of rings you’ll see when shopping for a chain. You won’t just see O-rings, but X-rings, U-rings, and so on. What this indicates is the shape, the cross section of the ring itself makes. For example, a simple O-ring has a circular cross section like this, while this ProTaper chain actually has an XRC-ring, which has this weird looking cross section. The reason for this is to use rings that do the best job sealing in grease down here, while simultaneously creating the lowest amount of friction with the side plates here.
Another variation you’ll see in chains is in the master link, which is a link used to close the two ends of a chain into one continuous loop. There are two types of master links: clip-type links and rivet-type links. Clip-type links use a clip like this to keep the link in place. To install one, you simply snap it into place with a pair of pliers, and you can remove it the same way. These tend to be more common on small motorcycles and dirt bikes. Rivet-type links have pins that actually get riveted into place using a special tool like this RK chain tool. They create a stronger, more permanent link when installed, and you usually see these on street bikes and higher horsepower machines.
Okay, now that you know all about the anatomy of different motorcycle chains, let’s get into chain sizing and how to pick the right one for you. The main thing that confuses most people is how chains are sized. Chains use a weird numbering system with 3-digit numbers such as 420, 520, or 630 to indicate the size. So first off, let’s go ahead and decode that for you. There are two important things to keep in mind while you learn about chain sizing. First, all chain sizes are based on units of eighths of an inch, and second, there is an imaginary division between the first digit in these numbers and the last two digits because they indicate totally different things. The first number in the series, which for motorcycles is always a four, five, or six, indicates the pitch of a chain, or the distance between the center of each pin in the chain. This number indicates how many eighths of an inch are between the pins. So a four means there are four-eighths of an inch, or half an inch, in between the pins. A five means there are five-eights of an inch between them, and so on.
For the next two digits, insert an imaginary decimal point in between them here. Now this number represents the distance in between the inner side plates, also in eighths of an inch. So a 20 becomes 2.0, which is two-eighths of an inch, or a quarter of an inch, in between the inner plates. One thing to keep in mind is that this number represents only the inner diameter of a chain, not the outer, overall diameter. In other words, one model of 520 chain could have a much wider outer diameter than another 520 chain, even though the inner diameter is identical. To illustrate the size difference between chains, check these out. This is a 420 chain, which has a half-inch pitch and is relatively small. These bigger 520 chains have five-eighths of an inch between the pins. Five hundred series chains are what you’ll find on most street bikes. This monster here is a 630 chain, which you’ll find on some older models and really big bikes.
Okay, next, after the size number, you’ll often see a series of letters like K, XRC, BMOR, and so on. These letter indicate things like recommended application, ring type, and tensile strength of a particular chain. What these codes means varies by manufacturer, so you’ll have to check those individually. But one very important thing to keep in mind is to always buy a master link whose code corresponds exactly to the chain you’re installing it on. Remember, overall width can vary, even between chains of the same numerical size, so you have to make sure they are an exact match or the master link may not fit.
Another thing you’ll need to know when you buy a chain is the length, because they come in lengths from as little as 80 to 140 links or more. To determine the length of chain you’ll need, you can use two methods. The easy one is just to check your owner’s manual or Google your model of bike to come up with a figure. If you can’t find that, you can just throw your bike on a rear stand, mark a link, and then count them all up. But if you’re doing a sprocket conversion and don’t know how many links you’ll need, know that generally, a 120-link chain is a safe bet. Almost every street bike will use less than 120 links, so you can shorten your chain with a chain tool to get the perfect fit.
Now let’s talk about chain strength and chain stretch. When shopping for chains, you’ll see the strength of chains rated in terms of something called tensile strength. The meaning of tensile strength is a maximum 1-time load a chain can take without snapping, and for motorcycles, it’s usually somewhere between 7,000 and 11,000 pounds. Another important term is fatigue strength, which is the load a chain can endure under continuous use. This figure is only a fraction of tensile strength, so it sounds a lot less impressive, which is why manufacturers always quote the higher tensile strength for their chains. Regardless, the important thing is to make sure the chain you’re buying is strong enough for the power of your bike. So always check the manufacturer’s application chart to make sure, like this one here from D.I.D.
Now another term you hear tossed around a lot with respect to chains is chain stretch. This refers to how a new chain increases in length as it gets used. First off, the idea that a chain actually stretches is a myth. Chains don’t stretch. If they do get pushed to their limits, they just snap. But what does happen as a chain gets used is that a tiny bit of wear occurs between the pin, the bushing, and the roller, which causes them to loosen up a little. But when you multiply that tiny bit of wear by over a hundred links, a chain can increase in length by quite a bit, making it seem like it’s stretching out. Don’t be alarmed if this happens. When you install a new chain, just make sure you check the slack and adjust it after the first few rides, and you’ll be fine.
Okay, last part of our chains crash course: how to maintain your chain. Chain maintenance is easy, but it’s surprising how many people never even touch their chains. There are really some nasty, neglected chains out there, so don’t be one of those people. There are only three parts of chain maintenance to know: cleaning and inspecting, lubing, and adjusting. So let’s go ahead and walk you through each one.
First, cleaning and inspecting your chain. When you clean your chain, use a degreaser or some WD-40 and a parts brush or a special chain-cleaning brush like ours. Just scrub it clean and wipe it dry with rags. While you do this, inspect your chain for wear too. Look for excessive wear by pulling your chain away from the rear sprocket. If it comes up enough to show half the teeth, it’s time to replace it. Look for hooked or missing teeth on your sprockets too, which are also a sign that they need to go. What you never wanna use on a chain to clean it is a wire brush, power washer, or steam, because those can destroy the O-rings or force water inside the grease pockets and ruin your chain. You can wash your chain with water and soap, but make sure you use some WD-40 on it to remove the water before you lube it. Side note, the “WD” in WD-40 stands for water displacement, and removing water from parts is actually its primary function.
Okay, second step: lubing your chain. Remember, on an O-ring chain, what you’re really doing is lubing the rings themselves, so you wanna focus on getting those coated. The best way to do this is to spray in between the side plates on the inside run of the chain, so centrifugal force will spread the lube outwards, coating the rings. A good time to lube your chain is right after a ride, when the chain is warm, so the lube has an easier time spreading through it. Chain lube needs some time for the solvents to evaporate and leave the lubricants behind, so don’t do it right before a ride or you’ll get a lot of the lube slinging all over your bike.
Third step is to adjust your chain. Generally speaking, chains need one to one and a half inches of up-and-down play in the chain to have proper chain slack. This is to account for the up-and-down movement of the rear suspension. Some people run a little more chain slack, which is okay. But what you definitely don’t want to have is too little slack, because the force of a compressed suspension combined with an overtightened chain can cause it to snap, and you’ll be in a world of hurt if that happens.
So that’s all there is to taking care of your chain properly, just these 3 steps, which you should do about every 300 to 500 miles. If it’s time to replace your chain, make sure to check out our other videos where we show you how to do it here, this one if you have a street bike, and this one if you have a dirt bike. Well that’s all for today, guys and gals. We hope you learned a lot from our little crash course on motorcycle chains, and that this helps you understand what you need for your own bike. If you have any questions, you’re more than welcome to ask us in the comments below or give us a call at the number you see on the screen, and our knowledgeable sales staff will help you out. And please remember to also subscribe to our YouTube channel for more helpful videos just like this one in your inbox every week. Thanks a lot for watching, and we’ll see you next time.