I just replaced the middle chainring on the Kaffenback, since it's done something over 6500 miles, and the tooth were rather sharp! Since I only occasionally use the other two rings, they're in perfectly good condition.
It proved remarkably difficult, and in the end I had to take the small chainring off as well, just to get enough room to move the middle one around and over the crank arm. It turns out that putting chainrings on with the chainset sat in your lap is a lot easier than doing it on the bike, with the frame, chain, and other crank arm all managing to get in the way. This Truvativ chainset needs two allen keys, one on either side, and inevitable one or the other always seems to be fouling something!
After that I tweaked the front changer slightly, and replaced the mount for the speedo, since the little bit that goes 'click' on the old one had fallen off, which meant that the computer wouldn't stay attached.
I should be pretty much ready for my Saturday 200k run now, aside from switching the light mount over to the right hand side on Friday evening, once I'm home and the pannier doesn't need to be on that side any more.
The only trouble is, Sainsburys will now be closed by the time I get there, so I'll have to go out first thing for some milk for my wheatybangs tomorrow morning.