Quote Originally Posted by Trek420
DebW "Sure glad they are a thing of the past. But if you've got an old Motobecane Mixte from around 1970, it probably has them."

yep, ah, so that's why my LBS has them sorta off to the side on the bike. Have to talk with them about semi-affordable replacement. But the Mixte is a keeper I think, she's gonna fit me and be the "urban assualt bike".
I didn't mean to imply that cotter pins are completely awful, just that modern cotterless cranks are much better. Cotter pins were used for decades and generally worked OK. You do need to remove them periodically to repack the bottom bracket. And you should have a spare set of pins because sometimes they get munged as you remove them. If you or your LBS can remove the current set of cotterpins and the crank and BB are otherwise in good shape, there is no pressing reasons to replace the whole setup. If you extract the cotter pins once a year to service your BB, they should never get stuck.

BTW, cranksets that take cotter pins are made of steel, not alloy. Steel is not as stiff and the chainrings can get out of round. You may also notice them flexing when you stand on the bike. Rotate the crank and look at the chainring wobble. Sometimes it's bad enough to cause the front derailleur to scrape. The good thing is that if the chainrings get out of round, you can bend them back with something like a large (18") screwdriver. It's kind of like truing a wheel with brute force. Gee, now I'm feeling nostalgic - never thought I'd miss steel cranksets. If you lived near me, Trek420, I'd be at your house tomorrow truing those chainrings.