Originally Posted by Laggard

What I carry:

Chain tool, frame pump, spanner, floor stand, TIG welder, crank puller, floor pump, third hand, fourth hand, truing stand, pedal wrench, bearing press, levers, hex set, sprocket chain, spoke wrench, two water bottles, cell phone, gps unit, $172.50, power bar, pork roast, spare socks, arm and leg warmers, spare spokes, flare gun, mace, a video of the 1992 Liege-Bastogne-Liege, bike lock, and on really long rides, a generator.

Seriously.

You might want to add a few things.