Road Bike Anatomy

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Get to know how a road bike works with our interactive road bike anatomy part guide. Click the part name to find it on the bike and read the description below.

Road Bike Anatomy

Frame
The frame is the skeleton of a bicycle. The most common type of frame is called a "diamond" frame, consisting of two triangles. The front triangle consists of: the seat tube, a center vertical tube. The top tube, a top horizontal tube. The down tube, a bottom diagonal tube. And the head tube, the front vertical tube. The rear triangle includes: the seat tube, seat stays, the rear vertical tubes and chain stays, the bottom horizontal tubes.

Saddle/Seat
The saddle, often called a "seat", designed for the rider to site on as they ride yet is not intended to support the rider's entire weight. Classic saddles are made of leather stretched over a metal frame that will mold itself to fit the shape of its rider.
Most modern bicycles come with plastic saddles which require no break in. Plastic saddles are also lighter and less expensive than leather.
Seat Post Binder Clamp
The seat post binder clamp secures the seat post into the frame’s seat tube. It may be a conventional bolt with a nut, an Allen bolt, or a quick release.
Seat Post
The seat post is the tubular support that holds the saddle and connects it to the frame. The seat post telescopes into the seat tube of the frame, providing the adjustment for saddle height. Many modern seat posts have a "micro adjusting" saddle clamp mechanism built into the top of the post that allows for fine angle adjustments of the saddle.
Brake Cables
Most modern bicycles use cables to control the brakes. Brake cables consist of two parts, an inner cable of twisted steel wire, and an outer cable housing.
In many bikes the housing doesn’t run along the full length of the cable, but transmits the compressive part of the load to the frame by means of housing cable stops.”
Rear Brake
The rear brake located over the rear wheel, usually attached to seat stay, is the primary brake for controlling speed and stopping. The rear brake is controlled by the right hand brake lever.
Tire
The bicycle rides on its tires. The tires are made up of three parts: 1 Two hoops of strong steel wire, called beads that hold the tire into the rim. 2. The nylon cloth cords forming the body of the tire, woven between the two beads. 3. The outer rubber holds it all in. The rubber is thicker where it contacts the road and is is called the tread. Most bicycle tires are not airtight by itself, so they use an inner tube.
Rim
The rim is the outer metal hoop of a bicycle wheel with a U shaped cross section. Although the spokes go through the rim it does not include the spokes.

Spokes
Spokes are the wires connecting the rim to the hub of a bicycle wheel. Spokes have a head, like the head of a nail, to keep it from pulling through the flange of the hub. Immediately after the head the spoke takes a right-angle bend, also known as the "elbow" of the spoke. The outer end of the spoke is threaded, and a special nut called a nipple fits through the rim and screws onto the spoke threads.

Spoke Nipple
The spoke nipple is the nut that secures the threaded end of a spoke to the rim of a bicycle wheel.
Freewheel/Cassette
A cassette, is the group of sprockets, or toothed rings, and spacers designed for use on a rear hub of a multi-speed bicycle. Some of the sprockets and spacers may be semi-permanently attached to one another by bolts or rivets. A freewheel is a form of rear bicycle wheel that has a device freeing it from the driving mechanism, as when the pedals are stopped in coasting.
Rear Derailleur
A rear derailleur is a mechanism for moving the chain from one sprocket to another of the rear cluster to change gears of a multi-speed bicycle.
A rear derailleur consists of a parallelogram which moves a cage with two chain pulleys, a jockey pulley and a tension pulley.
Chain
A chain is a looping circular set of links to transfer power from chainring to the cluster of gears on the rear wheel. The chain ring bolts to the crank arm spider.
Chainring
A front sprocket or toothed rings that attaches to the crank by being bolted on to a spider.
Crank
The crank is the arm, or lever, which extends from the bottom bracket axle and connects the pedal. Sometimes called a "crank arm".

Pedal
The pedal is the part you put your foot on. The axles of the pedals screw into the cranks. There are different types of pedals, platform pedals to step on and clipless that will bind your shoe to the pedal axel.

Water bottle Cage Braze-ons
A water bottle cage braze-on is a small fitting permanently attached to a frame allowing you to place a waterbottle cage on your bike.
Headset
A headset is the bearing assembly in the front of the frame that connects the front fork to the frame, allowing the fork to turn.
Stem
The stem connects the handlebars to the fork steering tube.
Handlebar & Tape
The Handlebar is is a tube attached to the stem. Attached are brake levers and shifters. Conventional handlebars are divided broadly into two styles: "drop" which are wrapped in cushioned tape, and "upright" which require a cushioned grips.
Brake Hood
The brake hood is the rubber covering above the brake lever. The brake hood gives another hand position on the handlebar of a road bike.
Brake & Shift Lever
Brake & Shift levers are levers on the handlebar to activate the brake or shift gears through a cable connection: Left side is front brake and front derailleur, right is rear brake and rear derailleur.

Front Brake
The front brake located over the front wheel, and usually attached to the fork. It is the secondary brake for controlling speed and stopping. The front brake is controlled by the left hand brake lever. If used by itself, your likely to be thrown over the handlebar.

Cable Stop
A cable stop is a fitting at each end of a piece of cable housing with a hole in the center, which will let the inner cable slide through.
Fork
The front fork consists of two blades that go down to hold the the wheel axle, the fork crown, and the steerer. fork is attached to the main frame through the head tube and the headset and secured by the stem.
Skewer
In a quick-release hub, the skewer is a metal rod that runs through the middle of the wheel’s hollow axle and attaches the wheel to the dropouts in the frame and fork. The skewer with have a quick-release cam and an acorn nut.
Hub
The center part of a wheel, to which the spokes attach. it consists of an axle, which attaches to the fork ends, and bearings allowing the wheel to revolve around the axle.
Valve Stem
The valve stem is the stem of the tire’s inner tube that sticks out of the wheel’s rim, with a valve on the end allowing you to fill the tire with air. There are primarily two types of valve stems on bicycle inner tubes sold in North America, the Schrader valve which holds the valve inside the stem as in most automobiles, and the Presta valve which has a narrower stem and the valve exposed on the stem's end.