Friday, April 13, 2012

When to replace your chain

I've heard people say they've had the same chain on their bike for years and don't see any reason to change it.

I agree, if a chain isn't significantly worn, keep riding it.  There's an argument for continuing to ride a chain that is worn but isn't skipping yet; if it ain't broke, don't fix it.  I don't agree with that argument when it comes to chains.

You have to eventually replace the wearing parts of a drive-train anyway, so why not ride stuff until it dies, then replace it all, every few years?

You could do that, but like riding tires until bald, which can be done, the performance will gradually deteriorate as the practical service life of the component is surpassed.

The risk of mechanical failure increases, and it's no fun to be stuck in the woods with a mechanical failure that could have been prevented.

If you change your chain early you retain performance and spend less money.  Buying more chains is cheaper than not buying more chains?  Usually.  If your chain wears past a certain point it accelerates wear on chainrings and cogs.  Buying a high quality chain that lasts a long time and changing it out at the right time costs less in the long run in my experience.  Cogs and chainrings last longer.

So how do you know when your chain is worn enough that it will start causing premature wear on the rest of your drivetrain?

When chain wear is at 1%.  This refers to the increased length in the distance between link pins due to wear.  Replace your chain when it is at .75% wear, before it reaches the 1% mark.

The old school method is to measure the distance over 6 complete links, which should be exactly 12 inches on the chains we put on our mountain bikes, which is usually a chain with a 1/2 inch pitch (distance between link pins).  A set of inner and outer links = one complete link.  If chain is 1/16 of an inch past 12 inches, it's time to replace.

Never mind figuring that out though.. just buy a chain wear tool.  I like the go - no go type for ease of use.


This Park tool works well.


Resting the tool on my current chain, it slides about halfway down the .75 side of the tool.  When the chain is new there is pretty much no travel down the tool.


Pressing down with a bit of force caused the tool to go all the way down into the .75 wear indicator level. Most people will wait until the tool easily slips down instead of needing coaxing, but I'm measuring a Shimano chain here, and I don't like Shimano chains so this gives me a good excuse to get rid of the chain a little early.  Besides, race season starts in a couple weeks and if a new chain is going to skip I want to find out now so I can start the season with all the new parts I need.

If you let the chain wear to the 1% mark there is a greater chance of chainring and cog wear which will cause a new chain to skip on old cogs and increase risk of chain suck.

Shimano chains work, like all chains do. It's just that with my past life as a shop mechanic for 10 years and all the years I've been riding I've personally had more trouble with Shimano chains than any other chain, either braking or short life span.  Chains are a lot stronger now than in the 80's and 90's and Shimano chains have improved a great deal, but in my experience Shimano still wears or breaks before a Sram or Wipperman.

So why do I have a Shimano chain on my bike?  It came stock with the Giant Anthem X 29'er I bought last fall.  I thought I would ride it out to see how long new Shimano 10 speed chains last.  This is the HG74 chain, from Shimano's middle of the trail but well performing SLX group.  A lighter rider riding in dry conditions not doing any sprints or hard riding, a casual rider, could get years of trouble free service from this chain.  I got three months.

The new HGX chains from Shimano, which this is one, are specially designed with specific inner and outer plates designed for purposefully climbing or descending gears.  It shifted well until the last few weeks when I started to get some chain suck.  The chain suck could be coming from a dirty chain or wear on chainrings, so I can't really place the blame fully on the chain.

The chain did shift well, but I would expect nothing less on a 100% new bike.

My favorite chain is Connex stainless steel, made by Wipperman, and is tested as the strongest, longest lasting chain you can buy, double and triple the life of Shimano and Sram chains.  I've never broken a Connex myself and have rarely heard of them breaking from others.

I like the Connex quick connect link, although the Sram link is easier to use.


Shiny new chain in the box.


No quick link on the Shimano chain so out comes the chain tool from the bottom of the tool box to remove the old stock chain.


Connex Quick Link - no tools needed.


Must instal the right way or the link will skip on small cogs (11T) and may fail.  No worries when put on the right way though.. like anything mechanical..


I haven't ridden this 10 speed Connex yet (rode the 8 and 9sp versions before).  I'll add to this blog entry in a few days after my first ride and let you all know if I found a difference in shifting between Shimano's special HGX design and the Connex design. 

I've put about 15 hours on this chain now.. raced it twice.   Shifting under load up hills with the Connex is slightly less smooth than with Shimano's HGX chain, but it works just fine.  I'd say it's the same as Shimano's non-HGX chains or any other good top end chain.  This is for sure a nit-picky difference..   Nobody is going to lose time on any hill climbs.  Shifting seems just as fast.  It has that familiar HyperGlide click/ mild clunk feel.

I think it's worth it for the extra strength and durability.

Update August 27 2012:  Connex chain has just started to show very slight wear after 5 months.  Not yet at 0.75 wear. Not yet as much wear as the Shimano chain had at 3 months.  I'm ahead of the game chain wear wise, but the Connex was about $100.00 and the Shimano about $30.00. I need four more months of use from the Connex for wear life/ cost ratio to be equal between the two chains.  I am ahead on another front though.. My last Shimano chain on my old bike broke twice within a couple months.  Why did I buy a Shimano chain for the old bike if I don't like Shimano chains?  I went cheap because I was getting a new bike so I bought a $30.00 Shimano chain.. Wasn't so cheap as I needed to replace it early.  I threw it in the garbage and bought a Sram chain for $50.00.  Had not problems with that one.

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