• Hex wrenches help you adjust different parts of the bicycle.outil multi fonction image by danimages from Fotolia.com
  
  Bicycle tools can essentially be placed in two different categories: shop tools and road tools. Shop tools are generally bigger, bulkier and more expensive. They help you repair or maintain the bike in a shop when the bike needs a thorough break-down or tune-up. These tools include clamps and truing stands. Road tools, on the other hand, are smaller, light and generally cheap, and are used to fix the bike on the road while you're traveling.
  
  

Hex Wrench

• A hex wrench is an essential tool for any bicyclist. Many parts of a bicycle are adjustable using a hex wrench. The height and angle of the saddle (more commonly known as the seat) and handlebars are all adjusted using a hex wrench. Most hex wrenches are multi-tools that have a few hex wrench sizes in one device. Common sizes include 4mm, 5mm, 6mm and 8mm.
  
  

Tire Levers

• Tire levers help you remove a tire from the rim and tube. A bike wheel has essentially five parts–the axle, spokes, rim, tire tube and tire. When a tube goes flat, a bicyclist has to remove the tire that surrounds it in order to put on a new tube or patch up the flat one. Sometimes this can be tedious and difficult work, particularly when it comes to putting back on the tire. Tire levers ease this job by giving you leverage. One end of a tire lever wedges below the tire while the other hooks around a spoke, holding the lever in place. The other lever can then be used to pry off more tire from the rim. In this manner, the entire tire can come off in seconds.
  
  

Bicycle Pump

• Even more essential than the hex wrench or tire levers is the bicycle pump. A bicyclist will quickly destroy his wheels if she does not ride with the tubes pumped up, and the only way to pump up the tubes is with a bicycle pump. Pumps generally work with both types of air valves that come with a standard tire tube: Schrader valve and Presta valve. Presta valves are more common to road and dirt bikes, which require high pressures in the tube, whereas Schrader valves are commonly found on tubes for commuter bikes.