Bicycle Repair Manual

1–BASICMECHANICALSKILLS ABOUTTHISCHAPTER This chapter has several sections. It should be read carefully to prepare for using all the other chapters. The first section is GENERAL TERMINOLOGY OF BICYCLE PARTS. This section covers only the most basic and universal terms. The other chapters will each start with a terminology section with terms that are more specific. The second section is THREADS. Understanding thread descriptions and thread types is perhaps the most important basic mechanical skill. The third section is PRESS FITS. Press fits are a means of holding pieces together other than by threading them. It is a system with its own unique set of techniques and rules. The fourth section is LUBRICANTS. Understanding the proper use of greases and oils is critical to being a good mechanic. The fourth section is CLEANSERS AND POLISHES. This section covers what types of cleansers, solvents and polishes might be used, and how to use them properly. The last section is TOOLS. This section covers use of common mechanic’s tools. The other chapters describe how to use bicycle mechanic specific tools. A list of recommended tools is in the appendix. Down tube: The lower tube of the frame that extends from the bottom of the head tube to the bottom of the frame (the bottom-bracket shell). Seat tube: The near-vertical tube that is at the middle of the frame, which the seat post slides into. Bottom-bracket shell: The portion of the frame that contains the crankset bearing parts, which are called the bottom bracket. Seat stay: The two tubes of the frame that start from below the seat and meet the chain stays at the center of the rear wheel. Chain stay: The two tubes of the frame that go from the lower end of the seat tube and meet the seat stays at the center of the rear wheel. Dropout: The fittings at the end of the fork, and at the juncture of the seat stays and the chain stays, to which the wheels are attached. Top tube Seat stay Head tube Seat tube Chain stay Down tube Fork Dropout GENERALTERMINOLOGY Bottom-bracket shell Dropouts OFBICYCLEPARTS 1.1 Parts of the frameset. Chapters on individual component areas of the bicycle have more specific terminology and definitions. For the purpose of this manual, the following terms apply to the frame and basic components. Frame: The structural piece, usually a number of tubes joined together, to which all of the components are attached. Fork: The structural piece that attaches the frame to the front wheel. The fork turns to allow the rider to control the bicycle. Frame set: The frame and fork combination. Head tube: The near-vertical tube that is the forward most part of the frame. Top tube: The upper tube of the frame that extends back from the head tube to the seat tube. Derailleur: There are two such mechanisms: a front derailleur and a rear derailleur. The front derailleur moves the chain between the selection of gears on the crankset; the rear derailleur moves the chain between the selection of gears on the rear wheel. Chain: The loop of links that connects the front gears to the rear gears. Freewheel: The set of rear gears. Freewheels and freehubs have a confusing overlap of terminology. For clarification, see the terminology section of the chapter regarding these items. In a general sense, the freewheel is the set of gears that the chain turns in order to apply drive forces to the rear wheel. 1 – 1 1 – BASIC MECHANICAL SKILLS Crankset: The mechanism that is turned by the rider’s feet. It consists of two lever arms called crankarms, one to three gears called chainrings, and a bearing assembly that the crank arms rotate around called the bottom bracket. Bottom bracket: The bearing assembly that allows the crankset to rotate in the bottom-bracket shell. F ro n t d e ra il