Roadside Assistance

While a fellow cyclist can help with most issues, not much you can do about a lost crank bolt; unless, you have a crank bolt with you and a tool.

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I had the crankbolt on my fixie strip while I was riding it home. That sucked.

Who makes a crank bolt out of aluminum? It was always coming loose anyway. I put in a steel bolt and haven’t had any problems since.

I have titanium crank arm bolts on two road bikes.  In each case, I use a steel version to crank tight the arm.  Then I remove the steel bolt and install the titanium bolt.  The stronger steel bolt compresses the arm onto the tapered spindle and the titanium, or aluminum as in your case, to keep things in place.

The issue that people should be thinking about is the condition of the crankarm.  If the square taper of the arm is mangled, you’ll never get the crankarm to stay tight.  A lot of people come in to get new bolts or get their cranks “tightened”, but I know that they’ll just have the same problem again in a few miles or a few days. You’ll have to buy new parts.

If your crank is loose, DO NOT continue riding.  You’ll have an accident or at least destroy your equipment.

I have one of those weird star-spline tapers instead of a square one. More surface area for contact I suppose, but it still comes loose. At this point I haven’t found a replacement that fits and I’m too cheap to buy a whole new bottom-bracktet and crank set up.

true, splined spindle cranks (both internal and external BB types) are not immune to that problem.  though Shimano designs do a lot better than others for the most part. 

when i call in warranties to a certain manufacturer, they don’t sound particularly surprised when i explain one of their cranks just fell off. 

anyways, the lesson is “check your equipment often”

Shall we mention carbon cranks and threads for pedal axles?

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