|Duck tape and zip ties - sorted.|
Sods law dictates that if a component is going to break, it's going to do it when you're furthest from home or help, when it's dark and preferably when it's cold and wet. Luckily last night it was a balmy 7 degrees and the rain had just stopped when my rear mech decided to part company from the frame. Also the mech didn't get tangled in the rear wheel and tear it to pieces (I've had that happen before too). The ride ended sheltering out of the wind waiting for the cavalry to arrive. I was able to call for a lift, far preferable to the long walk it would have been otherwise!
Does make you wonder just how prepared do you need to be for a ride? 'What if...' leads to 'where do you stop?' Should I carry a spare mech hanger now? The first time I attempted a proper long distance MTB ride (south downs in a day, 100 miles or thereabouts) I really wasn't sure how much stuff I should take. I ended up with a 25L bag stuffed full, mech hangers, chain, I think I might even have had a spare derailleur in there! It didn't last, I got to Devil's Dyke, where my wife was waiting to offer some moral support, and emptied the bag of all non-essential items! A lesson learnt. These days it's a saddle bag and whatever I can fit in jersey pockets. Lighter and faster. Well, definitely lighter...
My commute isn't really far enough to worry about having a full spare parts list in my bag - if anything I'll pack a chain tool and some power links so I can bodge something to get me home. And maybe a warm layer for when I do have to stop. Plus of course the zip ties and duck tape, that way I'll be equipped to fix near enough anything!