Along with Hex keys, I take spare tubes, a pump, and patch kitt. I also pack a Leatherman Skeletool for on-trail Mountain bike fixes. The Leatherman Skeletool is lightweight and has screw drivers, knife, pliers, and a bottle opener. So far I’ve only had to use the bottle opener to open a micro-brew on trail, but that alone makes this tool a must have on every trip.
Having the few tools to work on my bike was critical. Now I need to acquire more be a basic Level 1 Tool Kit, according to Zinn and the Art of Mountain Bike Maintenance. Many of the tools listed are everyday household tools that I already have, like pliers and metric wrenches.
Level 1 Mtn Bike specific tools:
1. 15mm pedal wrench This is thinner and longer than a standard wrench and thicker than a cone wrench.
2. Chain tool for disconnecting and reconnecting chains. I’m going with the $35 Shimano TL-CN32 pro tool
3. Chain-elongation gauge to monitor the condition of the chain
4. Spoke wrench to match the size of nipples used on your bike wheels.
5. Grease designed specifically for bicycles.
6. Rubbing alcohol for cleaning disc-brake pads, rotors, shocks, and internal parts.