These days, the Wera Zyklop Pocket ratchet is my go-to tool for any kind of bicycle-related maintenance. With a length of 140 mm and, in my specific case, a weight of 209 g it is small enough to fit in my hip pack. Get a few additonal bits to fit the particular requirements of your bike and you’ve got a fantastic tool that, because of its ergonomic properties, represents a significant step up on any of the traditional multi-tools.