Suburban Assault

My Crank Came Loose During My Commute To Work Last Week

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This Came Off Half Way To Work

I must admit, as an LCI, I have no excuse for this happening to me. One of the fundamental things that we teach our students is the importance of the ABC Quick Check. But, I got lazy – which got me into trouble.

Let me put some emphasis on the “C” in ABC Quick Check. “C” is for cranks, chain and cassette – essentially your bike’s drivetrain. Although not as important for safety, as “Air” and “Brakes”, the drivetrain is a very critical part of your bike’s ability to function. If you’re drivetrain isn’t working, you’re not going anywhere.

I had just finished a long ride the weekend before, where I had given the bike a complete check. Because of that, my lazy pre-commute inspection consisted of me squeezing my tires, then while rolling, spinning the pedals and doing a quick brake check.

Quite frankly, I’m not sure if I would have noticed the potential fail of my crank arm. Typically, when I perform the check on my cranks, chain and cassette, I’m just looking to see if the drivetrain rolls smoothly, not really ever torquing the crank more than a few pedal revolutions. This is usually done by hand and I would rarely pull the crank from side to side.

The signs were there from the start of my commute. As I pushed down on the left pedal, it made an incredible squeaking noise. I had recently installed my old pair of SPD clipless pedals for that previous weekend ride and I just figured that the pedal mechanism was in need of some lubrication.

As I reached the halfway point to my office (about 7.5 miles), I noticed that my left pedal was no longer squeaking. Within moments I felt it wobble. At first, I thought the pedal was coming loose off the crank, but when I looked down, I saw that it was the whole crank arm. I pulled over to inspect it and attempt a quick repair. I soon discovered that the bolt that held it in place required an 8mm allen wrench – something I don’t carry in my tool pouch.

My backup plan was to hobble to some nearby auto-repair garage and borrow the tool. That would have worked if it wasn’t so early in the morning, and all of the shops weren’t still closed.

The only thing I could do was push the crank onto the spindle as hard as I could and then thumb tighten the bolt. Because of that, I couldn’t really put any pressure onto that pedal. Fortunately, with my SPD clipless pedals, I was able to do most of the spinning with my right foot, while resting my left foot on the loose crank’s pedal. I had to stop every mile or so, to push the crank arm back on and re-tighten the bolt. Eventually, I made it to the office.

During my lunch break, my buddy ran me up to Home Depot, where I was able to purchase the correct tool. With that, I was able to repair the crank and get home problem-free. That day, I learned that I need to do a more thorough inspection of my bike before a long commute. A few moments before the ride can save you from bigger problems down the road – a lesson I’ll be sure to share with my students.


Written by dickdavid

May 28, 2013 at 7:10 pm

One Response

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  1. Target and Walmart are also good sources of emergency tools.

    Steve A

    May 29, 2013 at 9:15 am

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