Parts & Components of a road bike
There are many parts to the road bike. From pedals to brake cables each part has a purpose. There are many differences between the road bike and the mountain bike though. So take the time and see some of them. Below are descriptions of the parts on most road bikes. Use the image mape numbers, or just browse through the descriptions.
1: Pedals
The pedals are the first part of the leverage system. By pushing on the pedals you transfer your energy to the rear wheel and the bike moves forward.
2: Cranks or Crankarms*
This is the alloy lever that the pedals turn on. It transfers your energy from the pedals to the chain.
3: Bottom Bracket*
The bearing assembly by which the cranks are connected to the frame. The Bottom Bracket contains a ball-bearing. This bearing reduces friction as the crankarms are turned.
4: Chainwheel or Chainrings*
These are one, two, or three large sprocket(s) that are fastened to the crankarm assemble and turned by the petals. They allow for different gear ratios.
*2-4 make up the Crankset
5: Chain
A chain has about 100 links. Each link has its own bearing. It delivers energy from your feet to the back wheel of the bike by turning the freewheel in the back of the bike as you turn it with the chainwheel. Different gear ratios are possible by shifting the chain form one sprocket to the another.
6: Freewheel
The freewheel is a bundle of five (more or less depending on the bike model) gears attached to the rear wheel hub. The chain turns the freewheel which allows the rotation of the rear wheel. The freewheel contains a ratchet system to allow the bike to coast forward without moving the chain or pedals.
7: Front Derailer
This mechanism moves the chain from one chainwheel to another. It is controlled by a shift lever (9) on the left side of the bike.
8: Rear Derailer
This mechanism moves the chain from one gear to another on the freewheel. It is controlled by the shift lever (9) on the right side of the bike.
9: Gear-shift levers
These are usually referred to as shifters. There are two levers; one on the right side of the handle bars and one on the left. When the rider moves the gear-shift position the derailers select the different gear ratio.
10: Tension Roller
This is located in the rear derailer. This is a system of two small sprockets which provide tension to keep the chain taut. It moves with the chain as gears are shifted.
11: Hubs
The hubs contain the bearings for the wheel. The hub flanges usually have 36 holes for spokes.
12: Quick-release levers
This is a lever system which replaces a nut and bolt for fastening the wheels to the frame. The system is named as it is because it allows the cyclist to remove a wheel, or adjust his seat instantly without the use of tools.
13: Spokes
Each wire spoke has a wire nipple wick connecting it to the rim. The nipple is threaded. This provides a way to tighten or loosen the spoke which adjusts the wheel for stiffness, and removes wheel wobble.
14: Rims
These steel or alloy bands hold the tires and connect to the axle and hub assembly by means of the spokes.
15: Tires
There are two basic types of road biking tires available. The clinchers are for touring and recreation. The sew-ups are for racing and high-performance cycling. Each type of tire requires a different kind of rim.
16: Tire Valves
This is a device where you pump air into the tire tube to inflate the tires.
17: Saddle
There are two purposes of the saddle (seat). The first is to support you and the second is to place your body in its most efficient riding position in relation to the pedals and handlebars.
18: Seat Post
This is a steel or alloy tube that connects the saddle to the bike frame and can be adjusted depending on the rider's height.
19: Seat Tube
This is a frame tube that runs from the seat to the bottom bracket.
20: Top Tube
This is a frame tube that runs from the seat to the head tube.
21: Seat Stays
This is a frame tube that runs from behind the seat to the rear axle of the bike.
22: Seat Lug
This is a pressed-steel reinforcement that connect the top tube, seat tube, and seat stays to the frame. It has a clamping device which provides a way to tighten the seat post into the frame (usually by quick-release mechanism).
23: Chain Stays
These are frame tubes that run from the bottom bracket to the rear wheel of the bike.
24: Rear Dropouts
This is a lug attached to the end of the chain stays. This provides a junction for the chain stays and seat stays. It also provides a surface for attaching the rear wheel to the frame. The dropout on the right side often has a built-in bracket for fastening the rear derailer to the frame.
25: Head Tube
This is a frame tube that joins with the top tube and down tube of the bike.
26: Front Fork
This assembly holds the front wheel and connects it with the frame through a system of bearings mounted in the head tube.
27: Fork Crown
This is a metal assembly that joins the two fork tubes to the steering tube.
28: Front Dropout
These are also called the fork tips. These are lugs attached to the front fork tubes which provide a solid metal surface for attaching the front wheel axle to the frame.
29: Headset
This is a ball-bearing assembly which includes one bearing at the top and one at the bottom of the head tube/fork assembly. This system of bearings allows the front wheel to be turned while holding the fork in the frame. It is important that you have a good-quality headset so that you bike can absorb shock transmitted form the road through the front wheel while also allowing the bike to be smoothly steered.
30: Lugs
These metal reinforcements are used wherever one or more frame tubes come together.
31: Down Tube
This is a frame tube that runs from the head tube to the bottom bracket.
32: Handlebars
The handlebars are not only used to steer the bike but are a integral part of the leverage system by which the bike is powered forward. Pulling up on the handlebars also increases the force exerted on the petals.
33: Handlebar Stem
This is a metal clamp assembly fastening the handlebars to the front fork. They come is many different sizes, making the distance between the handlebars and the seat longer or shorter to accommodate individual rider differences.
34: Caliper Brake
These are either side-pull or center-pull brakes. They are shaped like calipers and press the brake pads against the wheel rim which in turn stops the bike.
35: Brake Lever
This is a hand lever, mounted to the handlebars, that allows the rider to control the brakes.
36: Brake Cable
This is a thin wire cable that runs from the brake lever to the calipers, controlling the brakes.
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