Tuesday, November 16, 2010

Chainring bolts and My Inner Voice

I got to go on a 20 mile ride last Sunday on the Perkiomen Trail.  I took my 3 year old with me in her trailer.  I had the feeling before leaving that I should check over the touring series iv, specifically the nuts and bolts to make sure everything was tight.  However, I did not do it.  Don't worry, nothing bad happened and nothing broke.  After about 10 miles though I noticed a knocking sound and feel in the crank, especially as the drive side pedal came over the top.  The immediate thing to check was the bottom bracket.  No, that wasn't it.  The crank arms were secure.  What about the pedals?  No, my cleats were secure, and the pedal spindles were not loose.  Hmmm, I wondered, what could it be then.  I continued riding and thinking.  A few miles later it dawned on me.  Maybe it is the crank bolts.  I should have stopped right then, and checked them, but I continued on home.  At home before putting everything away, and going inside, I finally relented to the nagging feeling I had to check the bolts.  Low and behold, a couple were loose; loose enough to be the cause of a knocking feeling and sound while pedaling.  I was happy to have the problem solved since I like a nice, quiet bike.  The crank bolts usually aren't the first thing to think about when dealing with a problem like that, but they are important.  A crank bolt could be easy to miss if it loosens enough to fall out.  I've seen what can happen eventually if a missing crank bolt is overlooked or ignored.  The chainring can bend and break due to the force that the chain puts on it.  This happened to a patron I worked with in the Community Bike Shop in Charlottesville, VA a few months ago.  He didn't know how his chainring had bent until I was looking it over and finally noticed one of the bolts missing.  Not only did it ruin his chainring, but it also ruined the front derailleur and the chain.  It all broke at once as he powered up a hill one day.  So it could also be dangerous by possibly causing you to fall, maybe even into traffic.  Don't forget the little parts of your bike.  They are just as important as all of the big parts, and some maybe even more so.


thomas said...

Darn, I would have put money on that mechanical problem, and I would have been wrong. While reading your post my initial thought was that the right crank was clipping the front derailleur cage when you were in your big ring. Possible causes would have been: bent crank, bent bottom bracket spindle, or most likely, bent or misaligned derailleur.

Halley Cotton said...

Same thing happened to me! I had three of my 5 chainring bolts fall out of my 1980's fuji boulevard. I've tried to find replacements and so far have struck out. Do you happen to know where to find some? Any help would be appreciated!

Matteo said...

Cotton: Any bike shop worth their salt should have them.