After having encountered 151 BCD cranks, I started poking around and found this good writeup on the history of the aluminum bicycle crank.
https://janheine.wordpress.com/2011/09/07/history-of-aluminum-cranks/
After having encountered 151 BCD cranks, I started poking around and found this good writeup on the history of the aluminum bicycle crank.
https://janheine.wordpress.com/2011/09/07/history-of-aluminum-cranks/
life in the so called space age 