A road bike frame defines the riding characteristics of a complete road bike. Bike fit and geometry is determined by the frame and how the various tubes are connected. A contemporary frame is comprised of a molded carbon fiber composite material featuring specific material layup configurations to balance stiffness and compliance, or flex.
A road bike fork is used to secure the front wheel and brake and features specific carbon composite layups to the complement the frame and its desired riding characteristics.
Rear shocks are found on the frames of full-suspension bikes. They typically separate the front and rear triangle, and are fixed to the frame’s linkage, allowing the rear axle to rise and fall to absorb the shock of bumpy terrain. Like forks, rear shocks utilize either air or coil systems for shock absorption.
Brake rotors are an essential part of the stopping mechanism on bikes with disc brakes. They are fixed to the hubs, and spin concurrently with the wheel. When the brake levers are pulled, pads pinch the rotor and stop the movement of the wheel.
Brake calipers hold the brake pads, and straddle the brake rotors. The pads are held in place by pistons, which are engaged by the movement of the brake lever. There are two types of brake calipers: hydraulic and mechanical. Hydraulic brakes are actuated by a heavy liquid (typically mineral oil) which pushes the piston, causing the pads to pinch the rotor. With mechanical disc brakes, this action is executed by a metal cable.
The hub is the part of the wheel which allows it to spin. At the center of the hub is the axle, which fixes it to the dropouts in the front and rear of the bike. Riding on the axle is a set of bearings, which allows it to spin. Finally, a flanged cylindrical shell forms the exterior. Front hubs spin freely in either direction, and their movement is only controlled by momentum or the bike’s brakes. Rear hubs feature a drive mechanism which rotates the hub when force is applied to the pedals.
Spokes are long cylindrical pieces of metal which connect the rims at the perimeter of the wheel to the hubs at the center. On one end, they have a hook shape which secures them to the eyelets of the hub, and on the other end they are threaded, allowing them to be fixed to the rim with small nuts called nipples.
Rims are the circular hoop-shaped components which form the outermost layer of the wheel. Typically made of aluminum or carbon fiber, the rim must be very stiff yet lightweight, to not compromise the rim’s shape or the bike’s efficiency. They have eyelets drilled through them, allowing the nipples to thread securely to the spokes. The walls of the rim feature subtle ridges, which serve as a place for the bead of the tire to form an airtight seal.
Tires are the inflatable rubber casings which the bike actually rolls on. They feature tread patterns with varying compounds and designs, allowing riders to find suitable grip in a variety of terrain and weather conditions. Tires are either inflated via inner tubes or a tubeless system, which typically consists of rim tape and a liquid sealant that helps prevent air from escaping.
Brake levers are the mechanisms that the rider pulls on to engage the brakes to slow or stop the bike. They are mounted on the handlebars, just inside the grips. Each brake caliper has a corresponding lever, connected to a mechanical cable or a hydraulic line. Most bikes have front brake levers on the left of the handlebar, and rear brake levers on the right, but some riders prefer the adverse, which is referred to as “motocross style.”
The shift lever is the mechanism that allows the rider to change gears on the bike. They are mounted on the handlebar alongside the grips and brake levers, and connect to the derailleur via a steel cable. When the shift lever is actuated up or down, it increases or reduces tension on the cable, moving the derailleur to a lower or higher gear.
Grips are the rubber cylinders on the ends of the handlebars which the rider holds to steer the bike. They are secured to the handlebars either by friction or a locking mechanism. Grips usually feature a hard plastic or metal end to protect the bike and rider in the case of a crash.
The handlebar is the bicycle’s main steering mechanism. It is clamped in the center by the stem, and rotates back and forth to maneuver the bicycle. Made of aluminum or carbon fiber, handlebars come in varying shapes and sizes. Width, rise, backsweep and upsweep—or the shape—are all factors that determine how the handlebar feels in the rider’s grip.
The stem is a simple mechanism, typically made of aluminum, that connects the steer tube to the handlebars. Stems feature two perpendicular clamps that are tightened by bolts. With varying stack heights and reach measurements, stems play a key role in how the bike handles.
The headset is the bearing system that controls the swivel action of the bike’s steering. With two cartridge bearings that sit inside the upper and lower cup of the headtube, the headset is designed to rotate cleanly and allow the bike to handle smoothly. The key to proper headset maintenance is the level of compression impressed upon it. If the headset is too tight, the bike will be hard to steer; if it’s too loose, the front end will rattle and could be unsafe.
The saddle is the padded platform that the rider sits on. It is clamped into the seatpost in a fixed position. Saddles should be horizontally oriented, to prevent sliding forward and putting excess pressure on arms, wrists, and hands.
The seatpost is a metal or carbon fiber tube that connects the saddle to the bike frame. In recent years, dropper posts have become increasingly popular. A dropper post allows a rider to adjust the height of their seat with a handlebar-mounted trigger, making it easy to connect climbs and descents.
The seatpost clamp is a halo-shaped clamp that fixes the seatpost to the bike frame. It is a simple mechanism and often features only one bolt, which can be tightened by a wrench or a quick release lever.
Like the headset, the bottom bracket is a cartridge bearing system. Instead of allowing the handlebars to rotate, the bottom bracket allows the cranks to spin. Bottom brackets are either threaded or pressed into the bike frame, and feature a hollow center that the spindle of the crank set fits snugly into.
The crankset refers to a pair of arms and a spindle that connect the pedals to the bike frame. The arms come in either aluminum or carbon fiber, and the spindle is typically aluminum. Cranksets come in a variety of lengths, catering to the varying lengths of riders’ inseams.
A chainring is a narrow, circular ring that features sharp, evenly-spaced teeth. The chainring serves as the bicycle’s drive mechanism. It is fixed to the crank set, and the chain runs along its teeth, allowing the bike to move forward as the rider pedals.
A chain is a continuous loop of metal links, and a key part of a bicycle’s drivetrain system. By connecting the chainring to the cassette, the chain rotates the rear wheel as the rider pedals. The width of each chain varies, and is specific to the amount of gears on the bike’s cassette. Like all drivetrain components, chains only function properly with compatible drivetrain kits.
Pedals connect the bottom of a rider’s shoes to the drivetrain of a bicycle. They consist of a platform or clip, and a threaded spindle which attaches to the crank arms. There are two types of pedals: clipless and platform. Clipless pedals feature a locking mechanism that attaches to compatible shoes, giving riders more efficient power transfer. Platform pedals feature a flat or concave metal surfaces that is fitted with metal pins to form a secure connection with the bottom of the shoe. Because pedals are not universal, and vary by rider preference, they are often sold separately from complete bikes.
The cassette is a cone-shaped stack of chain rings which is fixed to a bicycle’s freehub body. Each ring features a different number of teeth, allowing riders to change how much distance they get out of each pedal. The larger (low) rings make it easier for a rider to climb, and the smaller (high) rings come in handy when a rider is descending or moving at a high rate of speed.
Arguably the most technologically advanced component on a bicycle, the derailleur serves as the mechanism that guides the chain on to different rings of the cassette. When a rider shifts gears, it is the derailleur that guides the chain on to a higher or lower gear. Consisting of a spring-loaded cage and two pulleys, a derailleur’s position is dictated by the tension of the metal shift cable, or in some cases, by an electronic signal. It was common in past years for a bike to have a front and rear derailleur, because many bikes had two or three chainrings in the front. In recent years though, drivetrains have been simplified, and front derailleurs have been phased out and replaced by cassettes with a greater range of gears.
From Main Street to the highest peaks and back to the river, we have the equipment you need to enjoy your favorite mountain pursuits!