I just moved from Cleveland to a city in Virginia and brought my two fixies with me to use as commuters. Things were fine for awhile, difficult moving up and down hills on a ratio designed for minimal elevation changes, but generally ok.

And then things started falling off my bike. I started losing chainring bolts (one or two at a time) with others loosening. Even more worrisome, my left crank arm started loosening all by itself. I've heard of stuff loosening before, but never something as substantial as a crank.

The hypothesis I've been running with for the time being is that the added strain of hard back pedaling + mashing up a ton of hills has been raddling things loose that would otherwise be solid.

Any suggestions for fixes would be much appreciated. I've gathered that steel might hold better, but I'd rather not have to replace crank arms, chainrings, and bolts all at once.

Cheers