Originally Posted by
auchencrow
- Cottered cranks are beautiful.
- They are extremely durable.
- You don't have to worry about crank bolts coming loose.
- You wont be pulling the threads out of your crank arm
- You only need one cotter press (vs ISO,TA and SL pullers).
- They ARE easy to work on in most cases. (It only takes a little finesse to fit cotters).
- Rarely, they can be hard to remove even with the right tool, but you can still salvage the crank arm by drilling or drifting out the cotter.
- You don't have to worry about wear in the chamfers of the square drive.
...
I have broken two left cranks while riding. The first, a 1960 Agrati on my first 1960 Capo, broke across the spindle eye as I was starting across Wilshire Bl. on Westwood Bl., for those familiar with the UCLA area. I managed to get across this huge intersection -- the busiest and largest in west Los Angeles -- and 3 miles home with the left crank timing advanced by about 30 degrees. The breakage shook me up, but did not dump me. The second, a 1970 Sugino Mighty Compe aluminum, broke across the pedal eye during an out-of-saddle climb. That one did throw me to the ground, causing minor injuries, and I had to ride the bus most of the way home. After the shock of falling, it took me a moment to see what had happened, because my left foot was still clipped into the pedal, but the pedal was no longer attached to the bike.
I am keeping the original Agrati cottered crankset, with aftermarket aluminum Simplex rings in my preferred 49-46 size, on my current 1960 Capo. Agrati, aka Magistroni, made a high-end cottered crankset, with the drive side crank and the spider forged as a single unit.