My Audax bike's chainset had worn out, it was Tiagra and had come to the end of it's days, slipping on the chainrings and missing gears on the rear cassette. It was fine until I cleaned the chain thoroughly and then it started to play up. So I changed the whole lot for Shimano 105 and it only took me 45 mins to replace it all and with a few tweaks it now works perfectly. I am quite chuffed with myself. Have any others done something that worked first time, and what was it?