Improper use of a tool can easily damage it, or damage the bicycle.
Bicycle mechanics use wrenches more than any other type of tool
The road tool kit is the most important one. It gets you home or to a bicycle shop.
What tools should you carry with you?
Stories abound of bicyclists who go on tour carrying 10 or 15 pounds of tools with them, ready to fix almost anything on their bicycles. That might be reasonable for a traveling bicycle repair service! On the other hand, a road racer to carries no tools at all. The team mechanic follows in the team car, ready to supply a replacement wheel or entire bicycle as needed.
On the third hand, a utility bicyclist, tourist or racer on a solo training ride should have a tool kit which avoids a call for a ride from afriend, spouse or taxi for 95% of on-road repairs. A reasonable toolkit keeps the weight down to a pound or two and covers the most common on-road repair needs. The weight can be even less on a modern bicycle which exclusively uses Allen wrench fittings. Here's my preferred list:
Especially if you are traveling in rural areas, you do well to carry a few supplies:
Improvised tools for road repairs.
These should cover most repairs for anything short of a tour into very remote areas.
Knowing how to use tools --
Hardware-store tools: Combination wrenches 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 19 mm. Screwdrivers, flat and #2 Phillips. Nutdrivers 8, 9, 10 mm (http://www.sheldonbrown.com/nutdrivers.html) Metric Allen wrenches, 2-6, 8, 10 mm. Maybe 7 for some old stems. (L-type, plus "T-handle" and/or screwdriver type handle in 4 & 5 mm. Balldriver preferred. Vise. Bench grinder. Hammer. Heavy rubber mallet. Plastic or rawhide mallet. Small round file; half round file. Pliers --------------------------------- Bike specific tools: Chain tool Cable cutter Headset wrenches Cone wrenches: 2 x 13mm, 15 mm. [2 x 14 mm, 16 mm, 17 mm] Bottom bracket tools 4th hand ...see: http://harriscyclery.com/toolsThe text continues and possibly ends here. This part might be empty for a short page. This part has a 10% indent on the left and right of the paragraph.