Sunday, November 11, 2012

Of chains and things #bikedc

I broke my chain this week.  Here's what I learned.

First, it is pretty simple to put a chain back together.  I got a Topeak Super Bicycle Chain Tool chain breaker from Santa Amazon, took the busted link off my chain, and spliced it back together. The Topeak tool got good reviews, and comes with a hanger thing that holds the chain in place for you as you splice it together.  In the video below, the bike dude made his own hanger out of an old spoke. 

Of course, while waiting for Santa Amazon to deliver the chain breaker, I had to ride the subway *s*h*u*d*d*e*r* Never again.  So when I dropped off a neighbor's thrown out bicycle at Phoenix Bikes, I asked if they just might have a gigantic bicycle.  Turns out they had a 25" urban Trek!  It is karmic balance I believe: if you bring a bicycle to drop off to Phoenix Bikes, you should leave with one as well. Backup bicycle = insurance against subway and some other fun.

So back to my bike.  The chain broke for a reason.  And that reason might be that my @#$@^ derailer (excuse me) has been misbehaving.  According to one LBS, which made a very nice DIY video on rear derailers, the solution to any derailer problem is to bring it to your LBS.  Ah..... no.  Another solution might be to listen to another LBS.... which I did....  This LBS said that two big evils for derailers are the stays and a gunked up housing.  

Photo from Rock & Dirt Blog
I cleaned everything, adjusted everything, and still, my derailer was misbehaving.  So I when to Velocity Bikes, a bicycle co-op in Del Ray where you rent tool time, and the volunteers install wisdom in young converts. Funny thing: 4 pm on a beautiful Saturday and the shop was all but empty.  No problem getting tool time.  And the dude in the shop was fantastic.  Taught me how to swap out my housing, taught me how to adjust the stays and the barrel correctly.... and taught me, when all was said and done.... that my chain was toast. Using a chain measuring tool that looked a bit like this, he showed me that my chain had "stretched" and needed to be replaced.

* sigh *

Apparently the links of the chain are half an inch link to link.  An easy way to test whether the chain is stretched and needs to be replaced is to measure 12 inches of the chain.  The 0 inch mark should be on one pin of the chain; the 12 inch mark should be on another pin.  If its off the 12 inch pin by less than 1/16th inch, that's okay. If its more, but less than 1/8th inch off; time to change the chain.  If its more than 1/8th in off, then its time to change the chain and the cassette as well. [Bicycle Life]

The chain and the cassette wear out together.  If the chain gets stretched and no longer fits in the cogs, it will wear the cogs until it fits again.  If the cogs get worn, then the cassette needs to get replaced along with the chain.

Or you could change your chain more often and make sure you cassette doesnt wear out.  How often?  A number of blogs suggest once every 2000 miles - but that's more of a guideline than an actual rule.  Weigh more?  More often.  Go grinding up hills like the Custis Trail? More often.
Photo by Mo Kaiwen (cc) Flickr
So I figure, that works out to about twice a year for me. Going for a measurement will tell you for sure.
My old chain had a quick link in it (a little link you can squeeze together and it comes apart).  This has been quite useful as my bike has what I think is a design defect with the front cogs, permitting on a bad day the chain to jam between the cogs and the frame.  So I went to my local LBS and bought a new 8 speed (count the number of cogs on your back cassette to know how many speeds you have if you are not sure) chain with a quick link. Oh yeah, and a new bell for my new backup bike.

30 years ago I graduated from college, and with my new piece of paper, I took a job that studying Hobbs, Kant, and Kierkegaard prepared me for.  I became a bicycle courier.  I bought a steal FUJI hybrid, one of the first, and made money the old fashion way: dodging taxis.  I sat in the basement of the Reagan White House reading Marx waiting for a pick-up.  Back in the good old days, I would go home, wipe the chain off, and feed it a couple of drops of oil.  Not any more.  A chain has become a delicate thing that needs constant cleaning, constant oiling, and replacing more often than I change the oil in my car! 

1 comment:

  1. I once met a bike tourist who told me he didn't own a car and lived a long way from a bike mechanic. So he would watch Park Tool videos then order the tools and parts and do the work himself. If he got stuck, he'd call Park and they'd help him out. Good company.