Chains by Mike T.

Page contents -

 Chain wear and its measurement

 Chain cleaning

 Chain lubing and a new magic chain lube formula!

Chain wear

When we talk about chain wear someone always mentions "chain stretch" and lots of people picture an ape of a guy with enough power to actually stretch metal.  This doesn't happen.  Chains grow in length because of minute amounts of wear between all the component parts of the chain.  When we have a chain of 100+ links and about five times that many parts then we have a great chance for even the smallest amounts of wear being magnified and easily measurable. 

A worn chain will quickly wear all other parts of the drivetrain - cassette teeth and chainring teeth.  If the parts are too worn when we replace the chain it will skip over the teeth of the old cassette and we will feel and hear a bang-bang skipping as the chain rides up and skips to the next tooth.  It might only do this in one gear - the one you use the most (and the most worn).      If it's really badly worn (see the pin above and the explanation below) then the chain will actually skip on the chainrings - usually with bad consequences.  You might go over the handlebars.

            It has been proved that measurable wear of under 1/16" over a 12" length of chain is acceptable and will not cause undue wear on other components.

 The pin shown was taken from the worst worn chain I have ever seen.  It was worn to 3/8" over the length of a new chain in a span of 12".  The wear  was so bad that the chainrings as well as the cassette had to be replaced.

Measuring Chains for wear

To decide whether our chain needs replacing or not we can do a simple measurement that takes a few seconds.  As stated above, all the little imperceptible wear points all add up into something we can see and measure easily.  All we need is a steel ruler or tape.  Try to measure as accurately as you can and start AT the front edge of a pin and measure TO the front edge of a pin 12" away.  Like this -


This is where to place the tape to start the measuring process.


This is the famous +1/16th mark.  If you replace the chain now you will not have to replace any other parts of the drivetrain.


Ahhh you waited too long and I'll bet money your gears skip and you'll have to replace the cassette.



With  measurements  around the 1/4" mark you will probably have to replace the chainrings too.  Sorry!

The 3/8"measurement on the left produced the badly worn pin shown above.  It's the worst chain I've ever seen.

In Summary -  Rules of Thumb -

Chain worn between -

Zero to +1/16" - You're ok.
+1/16" - Replace chain.  If no gears skip you're ok.  If it skips then the cassette is toast.
1/16" to 1/8" - Replace chain and cassette.  New chain will skip on worn sprockets.
1/8" to 1/4" - Replace chain, cassette and chainrings.  Check all chainrings for hooked teeth first.

Cleaning your chain

Of course there are many ways of cleaning your chain but I'm going to give you the one that works well for me.  Sure you can buy the fancy chain cleaning devices or remove the chain and scrub it in a pan of solvent but this is too slow and tedious in my opinion.  I like to do it quick & often.

Method 1.  

Here's what I do if the chain is very dirty with mud or sand - the type of stuff we pick up on mountain bike rides and rarely on road rides - get a garden hose and place the nozzle touching the top of the bottom run of chain with the nozzle pointing down.  Now blast the chain while backpedaling by hand for a couple or three revolutions.  If the chain is very oily, first brush on your favorite bio degreaser with an old toothbrush or something similar like a Park gear brush (verrry handy!).  Let the degreaser sit for a while and then give it the hose blast treatment.

Next, soak a piece of rag in WD-40 and grab the bottom run of chain with the rag.  Back pedal the chain through the rag.  This helps remove any stubborn dirt and displaces the water.  Do not let your wet chain sit before this step!  It will rust.

If the chain is still dirty - and a bit of dirt is ok - then feel free to repeat the above steps.  If your chain is not too dirty just do the WD-40 bit on its own.  This is the step I usually perform - method 2 below.

Lubing - find the Powerlink and using it as a reference point, place one drop of your favorite lube on each roller.  Make sure you keep going until you reach the Powerlink again.  Or mark the chain with chalk.

Warning!!  I'm a Firefighter by profession (now retired) and gasoline should NOT be used as a cleaning solvent!  It is extremely flammable and the vapors being heavier than air can creep unseen along floors until they reach pilot lights in water heaters and furnaces.  If you must play Russian Roulette then use gasoline outdoors away from any ignition source but what are you going to do with the dirty gasoline?  Huh?

Method 2.  This is the method I use the most.  By far.  The WD-40 method -  Spray lots of WD-40 on a rag and grab the bottom run of chain with the rag.  Back pedal the chain through the rag.  This helps remove any stubborn dirt as part of the WD-40 ingredients is a solvent which removes any greasy crud from the chain very effectively. Do the same again with a section of clean rag.  Repeat as much as needed.

Chain Lubrication

There are many types of chain lube on the market and their makers make claims that their lube is the most wonderful lube ever invented.  These lubes come in two basic types - dry and wet.  The dry types, advertised as not to pick up dirt, are usually of a waxy substance.  The wet types are usually made of an oil-based product and advertised to penetrate to the inner parts of the chain better.  I'm not going to argue which is better as there are good and bad points to both types of lube.  It usually comes down to user preference.

I've tried most of the lubes on the market of both types and all of them fail to please.  They seem to fail in two main areas - the don't last long (some of them less than ONE ride) or they pick up lots of dirt.  There are two things common to BOTH types of lube though - they are expensive and you don't get much for your money.

I have now found the ideal lube for ME and it meets my criteria for a good lube.  I'm never going to switch.  This is the end of my search.

This magic lube fills two basic needs - it lasts a LOT more than one ride and it's very inexpensive.  None of the fancy lubes can make those claims.  Right now it's about 6 weeks (and about 600 miles) since I last lubed my road bike chain.  Here's what it is -

It's a home-brew concoction of simple, readily available, inexpensive products that you will find at Wal-mart or other such stores.

I use a 50/50 mixture of synthetic motor oil and mineral spirits.  Get a liter of each and now you have two liters of chain lube for less than the cost of one dinky bottle of the latest magic lube.  Mix them in an old jar with a lid and pour some into one of your old chain lube bottles so you have the benefit of a drip spout.  Two litres of chain lube will last you about a decade of riding.  Maybe more.

The mineral spirits is just a paint thinner (or oil diluter in this case) which thins the engine oil so that it can penetrate into the insides of the chain.  It then evaporates leaving the original oil behind.  As chain lube is only any use when it's inside the chain and picks up too much dirt when it's on the outside of the chain, here's how I lube my chain.

1.  Clean the chain as above.  Method 2 is the one I use the most.  With a dry rag, remove as much of the WD-40 as possible.
2.  Drip one drop of lube per roller on the top of the bottom run of chain.  Try to spread it across the roller from side-plate to side-plate so that it has a chance to get down inside the chain.
3.  When you've gone around the whole chain, (mark the chain or use the power link as a visual point) run the chain backwards through a clean dry rag to try to remove as much lube as possible from the outside.
4.  Let the lube dry overnight and repeat step 3 before your next ride.  This final step is very important as lube on the outside of a chain is good for only one thing - picking up dirt.

You will notice some dirt buildup on the derailer jockey wheels.  Grip these with a WD-40 soaked rag and pinch them between finger & thumb while backpedaling.  This will get rid of the guck.

This is as simple and cheap as chain cleaning and lubing gets.  When it IS easy and cheap we tend to do it more often - THIS, in my opinion, has more effect on chain longevity than any magical wonder product.


My non-scientific chain lifespan test

Recently I removed a chain from my bike that I'd been keeping my eye on for a while.  Normally, I never pay any attention to how long a chain lasts me. I just change it when its wear gets close to the magic "+1/16th" measurement.  This one was easier to keep track of as it went on my new bike when I built it up, so I thought I'd keep tabs on it.

I lubed the chain throughout its life with my beloved Homebrew (detailed above), cleaned it only with my WD-40 and a rag method and I measured it occasionally.  I didn't keep track of lube intervals but I'll take a guess that it was cleaned and lubed about every 4-600 miles.  I don't intentionally ride in the rain and if I ever get caught in the rain, I clean and re-lube the chain before the next ride.  I'm in Canada and I get to ride the roads for seven months of the year and I ride the rollers indoors for the other five months.

So this recent chain, a SRAM PC 1071, was on this bike for three years.  It has done 8000 miles with another 3000 miles of roller riding, for a total of 11,000 miles and it was worn, to the best that I can see on my chain-measuring tape measure, about HALF the holy grail of +1/16th of an inch.  Why didn't I go to the full 1/16th?  Because I just thought that three years was long enough!  It owes me nothing.

So this lifespan was in spite of  minimal cost, home-mixed lube, applied whenever the chain seemed dry, infrequent low-tech cleaning and normal road riding by an average rider.  I'm not a muscular hunk who tortures bike parts and I average a reasonable 18mph for all my riding, which consists of hard interval training rides, hard hills and steady endurance rides.

Here is some more reading for you on chains -