We have had no mechanical problems for weeks on end, and then we get two. First, the spokes on RichardH's wheel came off worse in an argument with RichardF's pedal and the minor collision at a junction proved fatal for RH's bike. Although help was at hand as four others stayed with him, a phone call for a lift home was necessary. In another group MartinB showed us all how to break a chain and completely wreck a deraillieur, all in one go. The chain was so greasy (memo to MB - keep the damn thing clean) it was hard to hold, but eventually we were able to reconstitute the bike into a "get