Mountain Bike Maintenance

Fix your own bike…


with 14 comments


MTB chains come in two basic sizes, 7/8 speed or 9 speed. 9 speed chains are narrower (up to 6.8mm) than a chain for a 7 or 8 speed (up to 7.2mm). This means that it’s possible to use a 9 speed chain on a 7/8 speed cassette, but the spacing of sprockets on a 9 speed cassette is too close to allow a 7/8 speed chain.

The length of your chain is determined by the size of your bike’s largest gears. The chain needs to be measured so that it goes around the largest front ring and the largest rear sprocket, missing out the rear derailleur, with two (one inner, one outer) links to spare. How to cut a chain is described a little further down the page.

If you’re running a single chainring set-up (ie 1×8 or 1×9), you should try going with +4 links.

Shimano, SRAM, KMC* and Connex (Wipperman) are the main manufacturers. For 9 speed, the Shimano XTR/DuraAce (CN7701) is generally considered the benchmark as it is strong, durable and contributes to clean shifting.

*KMC produce allbut the XTR chain for Shimano.

Chain wear is dependent on many factors (lube type, conditions, environment), including, of course, how smoothly a rider changes gear (ie. not under full pedal pressure).

Chain wear, which is also know as ‘stretch’, occurs as the rollers become worn (see the top-left picture below; the left-hand roller is new, the right-hand roller has a ridge along the center of the interior surface which will correspond with the space between the two halves of the inner link plates), plate interiors and, most importantly, the pins (top-middle picture), effectively increasing the overall length of the chain.

The ‘working’ points of your sprocket and chainring teeth are a specific distance apart, which should match up to the distance between the rollers of the chain. As a chain wears, the distance between the rollers is increased. If the distance between the rollers increases by more than 1% of the original distance, the chain will begin to wear away at the teeth on your gears. Typically, your chain will wear first, then your rear sprockets followed by the front rings. Although a chain and gears used from new may operate well beyond 1% before the chain begins to slip off the gear teeth, once a sprocket is worn away beyond 1% it may not accept a new chain without slipping occurring so the gears must also be replaced. Manufacturers may specify their own limits, but growth of 0.75% can be taken as a good measure to replace your chain with the assurance that your gears will still be relatively unworn. Remember that wear will accelerate as the pins and links deteriorate.

The tool in the top-right picture above is a Park Tool CC-3 and could represent the best £/$6 you’ll spend on your bike. It’s an absolute doddle to use, taking literally seconds to confirm the condition of your chain, and could potentially save you a lot of money. The difference in cost between a new chain and the cost of a new chain plus a cassette and new set of chainrings or a crankset is almost certainly going to run into triple figures. Buy a chain checker and use it regularly. So, we’ll move on to getting the chain out of the drivetrain. For those of you who aren’t using a SRAM Powerlink or KMC Missing Link*, you’ll need to split the chain by pressing out one of the connecting pins. It is possible to re-use the pin on 7 and 8 speed chains, although Shimano recommend, as would I, re-joining all of their chains by using new, reinforced connecting pin (variations shown on chart below). 9 speed chains must always be closed using a new pin. Anyway, splitting a chain is pretty much the same across the board, with chain tools coming in all shapes and sizes, but basically doing the same thing. The one in the pictures is a Newton tool that I removed from one of their multi-tools.

*earlier versions of the Missing Link were not re-usable. There is a small nub on the inside of each link plate which locks the device together upon installation. Packaging on the aftermarket MLs is marked “re-usable” where appropriate. As far as I know, this locking design was discontinued from about 2006.

To open, simply take a section of chain in each hand so that there is no pressure on the link and push the two halves together across the length of the chain so that each pin protrudes from the smaller section of the hole in the plate (left-hand picture). Now slide the pins towards each other until they are in the larger section of the hole (middle picture), enabling you to separate the two pieces and break the chain. Simple, eh?

Refitting is the opposite of removal; just make sure to ensure that both pins are sliding onto the ridge on each plate. It can take a little practice to be able to hold on to each end of the chain while trying to line everything up, but how quickly you do it really is just a matter of practice.

Powerlink/Missing Link

Opening the SRAM Powerlink or KMC’s Missing Link is straightforward;

Pinch the opposite sides of the link together…

… push the chains pins towards each other to open the link…

… the chain can now be opened…  Easy as 1, 2, 3…

Chain Lubrication and Cleaning

Chains are like underwear; change often and keep them clean” – some sage advice from MTBR member 23mjm.

There is a misconception that a “well lubed” drivetrain means that there is lots of lube on the chain, cassette and rings. The idea being that less wear will occur on moving metal parts because they have plenty of lubrication. Well, if the drivetrain was enclosed in a sealed box, as it is in most motor vehicles, this would certainly make sense. However, your bicycle drivetrain is entirely exposed to the environment that you ride through, dust, grit, water and all, so the truth is that the only lube that is useful is that which works between the inside of each roller (bearing), the plate/pin on which it sits and the areas where the inner and outer plates overlap. The external surface of the roller, the cassette sprockets, derailleur jockey wheels and the chainrings should all be as clean as possible. Any lube on these components will only serve to attract the dirt that will contribute to reduced shifting performance and the accelerated wear of the drivetrain.

It’s a contentious issue, I know, so what you’re about to read can be taken with however large a pinch of salt you like. It is my opinion that a bicycle chain can not be adequately cleaned and relubed if it remains on the bike. Chain cleaning machines do more harm than good as they douse the entire drivetrain in degreaser which needs to be washed away (all over the rest of the surrounding area) with water. Degreaser in such quantities is impossible to remove from the chain in particular, but also the cassette, no matter how long you spend rinsing and wiping, so will make redundant any fresh lube you apply afterwards. You also run the risk of degreaser/water working its way into hub or freehub bearings. It is for these reasons that I will always only recommend complete removal of a chain for cleaning.

On we go then, to the cause of much mechanical procrastination, argument and mud-slinging; the cleaning of the bicycle chain. There is much discussion about the ‘best’ way to clean a chain, and many products and systems all claiming to do it better than the other. I’ve tried the mechanical chain cleaners, various cleaners and degreasers and have come to settle for White Spirits, or Mineral Spirits as I believe it’s called in the US. My basic method is as follows;

  • Drop the chain into a jar 1/3 filled with spirits (doesn’t matter too much how dirty this stuff is) or your chosen degreaser and shake steadily for a couple minutes.
  • If you have the time, you could leave the chain to soak for 20 or 30minutes before giving the jar another shake.
  • Remove the chain and drop into a second container (I use a plastic flask with screw-on lid) with bike cleaner or washing-up detergent and some hot water. Shake well for a minute or so and then pour the dirty stuff away.
  • Fill the container up with more hot water and shake to rinse, emptying and repeating until the water is clear of dirt. Wiping along the chain with a cloth will give an indication of how much dirt is left between the links. There’s nothing to stop you going back and doing another shake in the spirits jar before repeating the soap and hot water rinsing process.
  • Dry the chain as best you can with a cloth or tissue paper. If you have access to compressed air, even the canned type, blast any stubborn water out of the links. Blowing hard works pretty well, too. Because you’ve used hot water the chain should be almost entirely dry by now. Just to be sure, put it in the sun or on a radiator and leave to dry, wiping occasionally to rotate the rollers and help any stuck water out of the chain.

(White spirits can be filtered through coffee percolator-type paper filters and re-used.)

There is an increase in popularity of ultrasonic baths for cleaning bicycle components, and chains in particular. These devices cost from around $20-30 for a small unit and are an excellent way to save you some time in your maintenance schedule. Typically, they’ll use a water/detergent fluid, although it is possible to get specific fluids for use in ultrasonic baths. Some people have achieved good results using mineral spirits or degreaser. I use water with a couple of teaspoons of dishwashing detergent in mine after giving the chain an initial soak and shake in a jar of mineral spirits.

There are many chain lubes to choose from and everyone has their favourite. After I’d been using Purple Extreme for a good while, one of my  local shops started selling ProGold Pro Link, so I deceided ot give it a crack. My experiences so far – a couple of months with mixed-weather riding – have been favourable. It doesn’t seem to last quite as long as the Purple, particlulary after wet rides, but it’s not a million miles off and is more than balanced out by how extremely easy it is to apply. Although Purple was recommended to be left overnight after application to allow the solvent carrier to evaporate, I found that in practice it usually required two or three days, depending on the ambient temperature, to be dry enough to not pick up too much dust on the trail (obviously only an issue in dry weather). The Pro Link still requires that it is left over-night, but come morning the chain can be wiped down with a cloth as and left bone dry and very clean. Assuming that the chain isn’t too dirty, ProLink can be applied a drop to a link at a time while the chain is still fitted to the bike, something that really wasn’t advisable with the Purple.

Whichever lube you decide to use, try to make your choice based on the conditions you’re riding in; you may have to use different products at different times of the year. Whatever you choose, you’ll invariably find that following the manufacturers’ instructions will yield the best results. I alternate between two chains; not only does it seem to prolong the life of both chains and sprockets, but it also means that I’ll always have a clean/lubed chain to throw on. I strongly recommend checking the MTBR reviews for specific lubes, finding out what other local riders use and, most importantly, trying out as many as possible for yourself. Again, following the manufacturer’s instruction will usually yield the best results.

Back to main guide…

Written by SteveUK MTB

March 18, 2008 at 10:27 am

14 Responses

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  1. Hi Steve

    Great article, been following your advice for last 3 months or so. However, I checked my chain wear this evening, and it’s now at 0.75% – and I’m guessing after only about 500km, which seems very short. Seemed fine about a month ago… I have another chain which I’ll start using, but that seems a short life for a chain?

    I was wondering what could have caused that. Things that come to mind:
    1) Leaving in white spirits / engine degreaser too long
    2) Perhaps using engine degreaser instead of white spirits?
    3) Last 6 rides I’ve only cleaned every 3rd ride – chain not too dirty though, so just re-lubed
    4) On some rides, when chain has got bit dirty and made rubbing noise on ride (water / mud on chain?), I’ve squirted some water on the chain while riding to try and clean. Probably done that on 4 rides total

    Any feedback would be great!



    October 16, 2008 at 8:31 pm

  2. I don’t think that 500km is too bad for a chain. Which one do you use? Which lube do you use?

    It has been suggested that leaving chains soaking in cleaning solvents has a detrimental effect. Most manufacturers will also recommend against using a degreaser, especially something as powerful as an engine degreaser.

    SteveUK MTB

    October 18, 2008 at 9:26 am

  3. I’ve been using a Shimano LX (HG73) chain with SRAM powerlink – replacement chain is the same. Replaced powerlink at same time.

    I’ve been using Weldtite TF2 plus with Teflon dry lube, and now onto Finish Line Dry, as per your recommendation – however, since it’s been winter here and there has been water and mud on the trails, I should probably have been using a wet specific lube. Squirting water on the chain while riding probably didn’t help either!

    I think I only left in spirits overnight and only once, but have been using degreaser almost all the rest of the time, where washing takes about 10 mins in the degreaser before other steps. Will switch back to white spirits (thinners in my case).

    The maintenance shop where I take my bikes to be worked on uses degreaser, which is where I got the idea – except that they probably normally only clean a particular chain about 1x per year, in which case it’s probably no big deal.


    October 21, 2008 at 12:18 pm

  4. Where did I specifically recommended Finish Line Dry as a chain lube? I do use it for many purposes, all over my bike, but found it to be generally unsuitable here in the UK, where I’m not sure it’s ever dry!! The Finish Line Wet is just way too sloppy for my liking. I’m giving Pro Link a run at the moment and finding it to be pretty good. Like the Purple Extreme, it gets applied and left over night before being ridden, but it dries faster and more completely; much, much less damp residiue on the links. I’ll give it a few rides now that the weather is turning really grotty and report back, updating the Chain blog if I think it’s worth it…

    Like I said, 500km isn’t necessarily that bad for a chain, especially one used over winter and especially one that’s had extra water poured over it!! Put it down to experience, I say, and try out some lubes that suit your environment/conditions a little better. If you’re not keen on paying out for the XTR chain (very durable), then you’d do worse than giving KMC chains a go. The X9.73 is around the price of the LX.

    SteveUK MTB

    October 22, 2008 at 8:19 pm

  5. What detergent is recommended to put with the hot water in the second jar in order to wash away the degreaser? Is hand soap strong enough or is something slightly more industrial required?


    December 4, 2008 at 9:12 am

  6. As described in the article, I use washing-up liquid (Ecover), which in turn gets rinsed away with very hot water.

    SteveUK MTB

    December 4, 2008 at 12:07 pm

  7. I read that ProLink actually has Mineral Spirits as part of its formula:

    “Prolink formula: the lubricating oil is not disolved in the mineral spirits but is miscible. That means the two liquids mix into one but at the molecular level one is not disolved into the other. So when the mineral spirits evaporate, it leaves the oil behind.

    “The mineral spirits cuts the heavier lubricating oil allowing it to have a lover viscosity and thereby allowing the product to penetrate into smaller spaces (between the chain rollers and plates) via capillary action or meniscus (similar forces, depended on the surface tension of the substrate). Once in place, the mineral spirits volatilizes (evaporates) leaving behind the thicker oil that remains in place because it does not evaporate as it contain higher molecular weight and therefore higher boiling point organic compounds in the C26 to C32 region. The thicker viscosity oil also resists heavier loads and thereby reduces wear and tear.”

    Wouldn’t this mean that Mineral Spirits is ineffective as a degreaser to remove the actual ProLink lubricant??


    December 5, 2008 at 4:51 am

  8. Excellent question. I’m at work here and would rather give this my full consideration. I also have a ProLink’d chain to clean when I get home, so I’ll get back to you as soon as I have something for you…

    SteveUK MTB

    December 5, 2008 at 7:21 pm

  9. Hmmm, the more I research this stuff the more I get confused.

    The KMC maintenance website out front states that you SHOULD NOT use degreaser or any solvent to clean the chain:

    They manufacture those chains and must know what they’re talking about, no?


    December 6, 2008 at 1:14 am

  10. I’ll try to incorporate into one reply my response to both your comments. I’ll be honest and say that I more or less disregard the advice of both KMC and Shimano. Shimano say use a cloth soaked in degreaser to wipe a dirty chain, while KMC, who manufacture the chain for Shimano, says not to use degreasers. Coming from an almost entirely experiential learning curve, I’ve found that I get the most mileage out of my lube and out of my chains (KMC X9 and Shimano XTR, so one from each as the XTR is manufactured by Shimano) if I clean them completely – to the bare metal – before relubricating, although it would appear that using ProLink would again perhaps alter my procedure a little.

    After pondering your question regarding the use of mineral spirit to clean a chain lubricated with ProLink, I would say that the spirits may actually be the ideal tool for complete cleaning. That said, ProLink actually allows the user to ‘clean’ the chain simply by being applied as it simply thins the existing lube rather than breaking it down, so a different approach may be required. The very fact that mineral spirits will not break down the working part of the solution, but rather that it will just thin the solution as a whole, means that, if it is deemed necessary, spirits can be used to flush heavy dirt from the chain before having its excess wiped away and fresh ProLink added to bolster the lubricating properties. My experiences so far, however, may suggest that off-the-bike cleaning may be a rare requirement…

    In the spirit of user testing, I’ve had the same chain on my bike since I started using ProLink about two months ago. Contrary to my procedure with the Purple Extreme, which takes too long to dry in the UK climate to be used in the same way, I’ve been applying ProLink to the chain while it is still in place on the bike. One drop will soak evenly into each bearing without an significant excess. I run the chain through a heavy cloth a couple of times when the whole lot has been lubed and then once again the next morning.

    So far, I’ve done a couple of hundred miles, including a couple of extremely rough rides through wet, sharp-sand laid trails, numerous commutes on salty roads, and all I’ve done to the chain is wiped and relube with ProLink. The cassette was scrubbed clean off the bike, as was my chainring and derailleur wheels, but the chain itself has always come up visually clean and free from the usual crunching when twisted laterally that signifies a grit-laden chain, simply by following the manufacturer’s application instructions. The heavier substance which remains after the mineral carrier has evaporated would appear to be resiliant enough to prevent too much grit from becoming embedded within the bearings.

    SteveUK MTB

    December 8, 2008 at 11:08 pm

  11. [a chain oiler] should reduce the time spent servicing a high mileage bike and extend the life of its transmission sufficiently to pay for itself reasonably quickly.

    Reviews are generally favourable, particularly for bikes used for commuting. I have not yet used it myself, but intend to fit it to my Moulton soon.

    (edited by SteveUKmtb)


    April 4, 2011 at 10:48 pm

    • I’d have to disagree. As I explain in the text above, the only place you need oil in a chain is inside the bearings. A chain oiler is really only going to manage to deposit oil all over the outside of the chain and across the gears/sprockets, where it’s neither use nor ornament. The chain is going to pick up more dirt than it ordinarily would. From my experience, a dry chain lasts longer than one which is permanently coated in oil (and all the dirt it attracts). The lifetime of cassettes is also longer. Using a quick lube like ProLink, and simply drying the chain with a cloth after a wet ride, is, in my opinion, better maintenance than just dowsing it all in oil. Chain oilers are a solution to a problem that doesn’t exist.

      SteveUK MTB

      April 8, 2011 at 9:00 pm

      • I agree regarding a “dry chain”. When you have oil present you create an abraisive slurry which necessarily feeds grit in the bearing surfaces. Personally, I don’t feel that using a water blast is a bad thing. It’s effective in getting rid of the surface grit that may find it’s way into the bearing surfaces.eventually. Even if there is slight rusting, the depth of rust is miniscule and it’s worn off within a few miles of use.

        What I’ve found to work well is wax (parafin), combined with a dry lubricant. Parafin itself is not a very good lubricant, but it holds the dry lubricant in place while not “attracting” and re-depositing grit.


        August 30, 2012 at 3:40 pm

  12. Steve how often would you recommend taking the chain off and using your cleaning and lubing steps listed above?

    Kyle Price

    April 11, 2012 at 12:42 am

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