Oh god, those are the worst. Maybe the serrations make it brake better, I'm not sure, but they sound awful.

My wife bought a Peugeot with steel wheels like that and simplex derailleurs for $50. It turned out to be a pretty decent bike once I spent about $150 replacing the wheels, derailleurs, cables, and shifters.

A lot of what I learned about bike maintenance and upgrades, I learned on that bike.

This is what it looked like when I was mostly done with it:



Looking at it now I think I was maybe a little overly generous with the length of the brake cables, and the labels on the tires weren't lined up with the valve stems, but at the time I was pretty proud of the way it all turned out.