Part 1: Chains
Motorcycle drive chains are a variety of roller chain. The roller chain is the only type of chain used on a motorcycle that I am currently aware of. If there are other types that deserve to be addressed, feel free to contact me and let me know and I’ll happily amend this article. Moving right along now, let get started.
A modern roller chain is generally made of some type of steel alloy and consists of five main parts: plates, pins, bushings and rollers, and seals (o-rings, x-rings , etc.). In racing applications non o-ring chains are sometimes used to reduce the drag the seals have on the chain and squeezing out another fraction of a horsepower, but most people use an o-ring type chain. The chain is a series of links that combine those parts into a continuous loop. Different manufacturers may configure them with slight differences, but the general layout is something like this:
The chain is looped around a sprocket with teeth fitting the gaps between the links to drive the chain around the pulley system it creates. Now let’s quickly go over each part, its purpose and how it functions.
- The plates are there to hold everything together. They flank the pins, bushings and seals to keep them pressed together and to give the chain strength and structure. They are exposed to high tension forces.
- The pins are the part of the chain to which the main outside force is applied. It transfers that force by pulling the rest of the chain behind it as the force is applied. They are surrounded by the bushings and are greased in modern sealed chains. The pins can be considered part of the outer plates of each link.
- The bushings are basically protective sleeves around the pins. The bushing helps hold the inner grease around the pins. They are free to rotate around the pin and help to reduce overall chain wear. The bushing is part of the inner plate of each link.
- The rollers rest on the outside of the bushing and are free to rotate reducing friction on the sprocket teeth.
- The seals are typically made of buna-N rubber also known as nitrile or NBR. They are located on the very outside of the bushing between the bushing and the plate and surround the pin. The purpose of the seals is to keep the grease that is inside the bushing from flowing out.
Now that we’ve gone over the parts and the configuration of those parts, we can look at a chain analytically and find out exactly what kind of stresses are present and what the rider can do to address each issue.
- The pins and bushings rotate within and around one another, but since they are greased and sealed from the factory, they are protected from corrosion and wear as well as they can be in such an application. The bushings are generally separated from the plates by the seals, but they can come into contact at times, so some wear may develop over time if not lubricated. The bushings and the rollers do not have any lubricant between their surfaces so without lubrication; they will rub directly on one another.
- The rollers have no lubrication on the outside surface and are the recipients of the direct contact and force from the sprocket teeth. Therefore, the bushings also receive a lot of wear and stress on their exterior surfaces.
- The plates connect one link to another and pivot around the pins. However since they do this independently of one another, the pivot points rub on one another which causes wear over time. The plates are the most exposed portion of the chain and are prone to rusting more than the rest of the chain and need protection to extend their usable lives.
- The seals are there to keep lubricant contained and contaminants out. Seals could potentially wear out from constant rubbing between the plate and bushing, but there is not much you could do about it and even if you could, it wouldn’t amount to much because the wear would stop at the face of the bushing at which point, the seal would still be intact and it could not wear any further.
So you see, there are a few points that need to be addressed. Most of them are solved by reducing friction, wear and corrosion. Because of the construction of the chain and the tight tolerances, delivery of a lubricant is also something that needs to be addressed.
Part 2: Chain Lube
Okay, now we have gone over the motorcycle chain components, the configuration of those components and how they operate and are stressed. So what can be done to assist the chain in performing its function? Simple steps can be taken to maintain a motorbike chain and the best ones all utilize some sort of lubricant. There are as many types of lubricants as there are methods of chain maintenance and they can all be used effectively in one way or another.
The role of a chain lube is fairly simple although it may be accomplished in a number of ways. An effective motorcycle chain lube needs to lubricate and protect. It should lubricate the chain’s own contact points internally as well as the contact areas between the bushings and the sprocket teeth. Chain lubricant should also protect the surfaces from corrosion. I would also add a third requirement in that it should remain in place and not be thrown or flung off of the chain, but that is just a personal preference that is shared by many, but apparently not all.
The most common types of chain lube used are:
- Any oil (used or new engine oil, gear oil, ATF, hydraulic oil, etc…..just not chain lube)
- Chain specific oils
- Chain specific aerosol lubes
- Dry lubricants like graphite or polytetrafluoroethylene (the chemical name for Teflon)
- Chain wax, paste or grease.
- General aerosol spray oil and penetrants
So I’d now like to go through these types of chain lube one by one and break them down by pros and cons.
- Any oil is better than no oil, but that’s about it.
Pros: Using non-specific oil such as engine oil or gear oil, new or used, is probably going to be the cheapest kind of product, so I suppose low price is a benefit. Those kinds of oils will tend to have decent anti-wear chemistry.
Cons: They would typically not be thin enough to really penetrate between all of the contact points so you could easily end up with under lubricated areas in the chain. They also do not adhere beyond the comparatively weak surface tension of the oil and so they will migrate and fling off the chain more easily than other types of chain lube. I would never suggest using used oil though for this purpose. Used oil will always be highly contaminated and may exacerbate corrosion rather than prevent it. It also could have particulates that would increase wear in the chain.
- Chain specific oils are liquid oils marketed specifically for us in roller chains.
Pros: They have the obvious advantage of being formulated for chain lubrication, so they should have some penetrating properties and well as friction modifiers to reduce friction within the chain. They may or may not have some level of tackifier to decrease the fling off from the chain and their anti-corrosive properties should be adequate.
Cons: They can be difficult to apply and can be very expensive when looking at the total value of the product.
- Chain specific aerosols have some inherent advantages that come with the aerosol packaging.
Pros: Because of the delivery method, the lubricant is heavily diluted in propellant and solvents which is beneficial to the application if utilized correctly. The thin viscosity of the solvents and propellants typically result in a better penetrating fluid allowing the lubricant to migrate into the tight tolerances of the chain contact points to create a fluid film barrier to reduce wear and displace water instead of trapping it.
Cons: These products can also be very expensive and somewhat wasteful if not applied correctly. They could contain very little product and a lot of filler, but this is completely dependent on the brand and product.
- Dry film lubricants are ideal chain lubricants in certain situations but are more commonly used in industrial chains.
Pros: A big advantage is that they basically cannot be flung off of the chain once dry and it can be difficult for water to rinse them off. They also generally form a very strong film where they are deposited and can be very effective friction reducers.
Cons: The disadvantages of solid film lubricants is that since they are a solid film, they can be rubbed off more easily so they may not last as long as fluid lubricants. They also have more difficulty in penetrating between the tight spaces between the moving parts so there is potential of under lubrication of the chain. If an area is rubbed clean, since they aren’t fluid, they cannot flow to fill in the gap like an oil or semi-fluid can. Another disadvantage is that they may take a long time to dry and set. When they are still wet, they typically are very prone to being thrown from, or fling off, the chain. Dry film lubricants tend to only have a single component to provide lubrication which limits its capabilities. They also tend to not provide much corrosion protection for the chain since the solid lubricants are rarely anti-corrosive chemicals.
- Chain waxes, pastes and greases are semi-solid lubricants or waxes that can be applied to the outside of the chain and then distributed to the rest of the chain during operation. If they are diluted in a carrier, then they are distributed evenly and then set and are free to flow when needed.
Pros: The benefit of these lubes is that they stay put wherever they are applied and from heat and centrifugal force become fluid enough to flow where needed when the chain spins. Waxes will melt and turn to oil to enter into the tighter spaces of the chain when friction is applied. Pastes and greases will have enough fluidity when stressed to perform similarly. Pastes, waxes and greases may incorporate solid lubricants as well as liquid additives which allows them to have the most diverse additive set and potentially the most balanced performance.
Cons: Again, these products can be very expensive when looking at the total value of the product and can be difficult to apply depending on the delivery method.
- General spray oils and penetrants have some lubricating properties but in general are not preferable to other kinds of chain lubes.
Pros: Their usual application is for rust protection by displacing water and some anti-oxidant chemistry. They tend to be very inexpensive and are readily available in almost any retail store.
Cons: By design they are fairly strong penetrating oils and tend to wash out the pre-packed grease over time which is undesirable since they do not provide adequate anti-wear in place of the grease. They are thin oils and do not form strong enough films to maintain separation between the surfaces so their lubricating properties are not at the same level as specific chain lubricants.
Part 3: Chain Maintenance
Okay now! We have gone over the chain mechanism and the different types of chain lubricants in detail. Let’s go into the different kinds of riders and how they maintain a chain.
Chain lubrication is a frequently debated topic and there are a surprising number of approaches on how to properly maintain a chain. The most frequent strategies I see are:
- Ignore it; a modern chain is lubed on the inside and doesn’t need additional lubrication.
- Use any lube you have on hand, that’s what we did back in the <insert nostalgic riding era> and we used 90 weight gear oil and it worked fine for us.
- Lube and clean with a chain specific lubricant periodically or when the chain looks dirty or the lube has worn off.
- Lubing and cleaning periodically, but using generic spray oil instead of chain specific lube.
- Lube and clean and lube and clean and lube and clean etc. at every opportunity with a standard aerosol lube or chain wax.
- Automatic chain oiler; set it and forget it.
I’m sure there are more, but I’m pretty sure most people will fall into one of those categories. They all have their upsides and downsides, but some of those strategies have some serious faults that I would like to make people aware of. Afterwards, feel free to choose your own method and I’ll tell you which of those people I am.
- Ignoring chain maintenance and relying on the pre-packed grease in the bushings is simply wrought with problems. After reading the first section of this article, I would hope I don’t even need to explain this one. In case you forgot, here is a quick overview of why this method is flawed. The grease in the chain only lubricates between the bushings and the pins. Therefore, the side plates, the o-rings and in between the bushings and the sprocket teeth are left unlubricated. This means quick stretching and wear of the chain.
- Using any old oil you have lying around including used oil is probably better than nothing, but nothing is about the only thing it is better than. For starters, used oil is loaded with acidic contaminants which will accelerate corrosion and will also have abrasive contaminants to accelerate wear. Let’s just say used oil is never really a good idea. If it is fresh oil, it has some good points and bad points also illustrated earlier. If it is all that is available, it would be preferable over nothing. The argument of “we used this back in the 50’s, 60’s, 70’s, etc….” is pointless. Technology advances; in lubrication as much as in mechanics. So you can either embrace the better technology or stay in the past. If you are happy with the older technology, I’m not saying don’t use it, I am just saying not to ignore the fact that there are better products for the job. Before you dismiss me as a hater of older technologies, I would point out that the most modern bike I currently own was built in 1987 and I am perfectly happy with all the bikes I own.
- Lubing the chain periodically means you are guaranteeing to clean and replace old chain lubricant on a regular basis. If it is at a set schedule of cleanings, there could be incidences like an excessively dusty ride, a rainy ride or deep water crossing that might have triggered the need for an early cleaning and re-lube but may be ignored because of sticking to a strict schedule.
- Waiting until the old lube has worn off leaves potential for negligence. It also means that the chain has been progressively losing its lubrication and is running on cycles of high level lubrication and under-lubrication. If you apply when the chain lube is worn off you might have the illusion that the chain doesn’t need to be cleaned. This leaves debris and abrasives that should have been cleaned out in the chain, so it is always a good idea to clean the chain on a regular basis.
- Lubing periodically with generic spray oil will have disadvantages laid out mostly in the second part of this article, but for the most part, you will only be preventing the chain from rusting. Water displacing oils and rust preventatives don’t offer much wear protection and will not slow down the wear rate by any significant time.
- Cleaning and lubing the chain on a regular basis are very good ideas. However you can definitely overdo it if you are trying to maximize the value of your chain and lubes. A good chain lube will persist and remain on a chain for a fairly long period of time without wearing off. It should also protect the chain from becoming too dirty during its time. Therefore, it should not be necessary to perform chain maintenance too often. Lubing a motorcycle chain too often with an aerosol or a penetrating lube in particular will result in accelerated internal wear due to the grease being rinsed out of the bushings. This will mean more chain replacements which are the exact thing you are trying to avoid by maintaining your chain. This method also wastes a lot of lubricant by not letting it live its full usable life.
- Automatic chain oilers seem to be gaining in popularity in recent years and for good reason. They are user friendly and easy to install on the frame or swing arm of the motorbike. They meter out oil or some sort of chain lube at either a set rate or at a user defined rate. They can either work by gravity, run off the battery or by vacuum created by the engine. The upside of this is that you just need to keep the reservoir full once installed and your chain is constantly lubed. It takes guesswork out of how often to lube and it should keep the chain relatively clean, from constant oil wash. There are a few downsides I’ve noticed with these systems though that may create problems. It isn’t recommended to use any other lube than the recommended one for the system due to its operation, but I am sure there are some alternatives if you are willing to experiment. You do have to have a certain level of trust in the automated lubing mechanism too because it may be hard to tell if it has stopped working before damage may be done. Although a constant application of oil should keep the chain clean, you could easily have build-up forming regularly and since the whole point is to not have to maintain the chain yourself, the chain’s cleanliness can be neglected more easily using one of these. These also have a high upfront and refill costs which are a significant factor in choosing this method.
Each method has its own benefits and detriments as I said earlier, but some are definitely better and some are definitely worse. Rather than take my word for which is best, you can decide for yourself based on the facts. I myself choose to lube my chain with a chain specific aerosol and to lube it either before a big ride or when it’s dirty and the old lube is worn away. I am not a meticulous maintainer on my personal machines so this method simply fits my personality and it works for me. It’s definitely not the right way for everyone, although I think it’s the easiest.
If you find that your chains stretch out prematurely, break relatively quickly or are chronically without lube, you may want to make a change. Pick your own method, do it the same way you’ve always done it, change it up and try one of the ways I described above. No matter what you end up doing, I hope after you have read this, you can clearly see the needs of the chain and make more informed decision when deciding how to maintain your chain and what products to use.