I retrieved the rustiest LeTour in the state and went to work this evening after supper. The seatpost came out first before I put the bike on the stand. I am so grateful that all the parts came off without drama or trauma this time! There IS a little bend in the left seat stay, but if it bothers me enough I'll figure out a way to straighten it - or maybe I'll just run it as-is. As bad as it looks, I think everything, including the chain, will work okay once it's cleaned and de-rusted.
