At about mile 40 of a 75 mile charity bike ride, one of my colleagues was having trouble clipping in and out of his bike.  For long range bike rides, we wear special cycling shoes.  The shoes mechanically connect to the pedals through a cleat inserted into a spring loaded device.   Along with spandex and really expensive road bikes, bike shoes are a distinguishing feature between casual riders and more serious cyclists.

cambirabike.com

My friend was unable to clip his shoes back into the pedals.  He was afraid his ride was done, and there were still many miles to go.  If we couldn’t fix the connection, he might end up as road kill.

I took a look at the bottom of his bike shoes to see if I could find the problem.  Along with the cleat, the clipping mechanism was provided by a metal ring which expanded slightly once the prong of the bike shoe engaged the pedal.  But the ring couldn’t expand, because a small space behind it was clogged with dirt.  A few miles back, my colleague had to momentarily visit the woods.  When he walked on bare earth, soil jammed into the small space.  The problem happened later when he clipped out and then couldn’t clip back in because of the soil clog. 

I used the edge of a small portable screw driver I had, cleaned out the spaces of dirt, and then the shoes were as good as new.  It was no big deal and I thought nothing of it.  But my friend was both grateful and amazed.  He is extremely talented and competent.  But he is a salesman.  He had no concept of engineering ideas which are second nature to me.  When I realized this, I was a bit proud and accepted my role as engineering hero for the biking group.  Then some miles later, they all forgot about my heroics and it was back to engineering anonymity.

wheelies.co.uk/blog