Breaking stuff…

Some cycling gear clearly has a lifespan. Tyres wear out. Knicks lose their stretch (and may become see-through). Chains elongate with use.
But what about the frame, the cranks, the seat post and the bars? I rarely think about these bits, but they too have a lifespan of some sort.

Aluminium is different from carbon, steel or titanium in that it will eventually fail no matter how you treat it. With the others, as long as the load never exceeds some critical threshold, they can last forever. Every ride is “wearing out” an aluminium component.

Yesterday I was riding up the hill I ride up every day on my way to work. I’ve ridden up this hill every day for around nine years - the length of time I have worked in the Woden area. But this time something felt wrong. I thought the cleat on my right shoe had moved. Sometimes that happens - the bolts wiggle loose and the cleat moves along the shoe sole. No, it was in the correct spot and seemed tight. Around 150 m later I got off the bike a second time and removed the shoe, checked the pedal. I couldn’t find anything wrong with either.
I jumped back on, around the corner and up the steepest part of the climb. On the second or third pedal stroke while standing up, my foot slammed into the ground. The pedal was still attached to the shoe and around 2/3 of the threaded pedal hole from the crank was still attached to the pedal.
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IMG_3147

There is a dark portion that was cracked for a long while - the movement and open nature of the crack leave it dark. The bright bits are what let go yesterday.


I have been planning to retire the commuter bike for a few months now - in fact I have begun the process of replacement (but that is for another blog entry) - issues beyond my control have slowed it up. I was going to sell off the bike for a few hundred dollars but now I am rethinking that option. I think it needs to be fully retired - hung up and never ridden again.

In the meantime the old cranks are going back on the bike (Dura Ace 9spd that I didn’t even know I’d kept until they popped up in a box recently).


I estimate around forty-thousand kilometres covered by these cranks since new. I don’t think that is good enough. They should last twice that!
I wonder just how long carbon cranks last? In theory, they shouldn’t fail at all if they are well designed. Since my MTB has carbon Eagle cranks on it, and my next 2 new roadies will have Campagnolo carbon cranks on them - I guess I have a way to find out.