My friend Ki has like a 2001 Trek 700 with a Shimano C-101 rear derailleur, reverse action. The other week he was in a bit of a fender bender and had to replace the rear wheel. When he got the new one from the bike shop he asked me for a hand getting it on. I ran the rear shifter through all seven gears and it seemed fine. But when he took it for a test ride he came back with the chain stuck between the the outer cog and the chain stay. So I pulled out the chain and set everything back into position. Dunno how it could have happened because the guide pulley doesn't go beyond the smallest cog. But the derailleur is old and maybe flimsy; is it possible that it has become double jointed and pulls in the wrong direction? Ki is afraid to shift now when he rides it and I can't properly test it for him on the road because the bike is way too small for me. Has anyone else had a similar experience with the C-101 or have any advice? Thanks.