Glossary of Mountainbike Parts
*Bar-end Shifters These can be over the handlebar index shifters, non-indexed, thumb shifters, or twist grip shifters.
*Bearings are located on the axle, pedal, and crank. Cup-and-cone ball bearings on the axle can be dis-assembled, tightened, and lubricated. The crank bearing is usually sealed.
*Bottom Bracket This is where the down tube, seat tube and chainstay join and houses the crank and crankset. It houses either an adjustable bearing or a cartridge bearing.
*Brakes These can be cantilever, hydraulic, v-brakes, or u-brakes.
*Brake Pads These contact the rim, or disc if hyd
raulic, and are easily replaceable. They come in a variety of shapes and materials.
*Brake Levers Most levers are now adjustable and come in different lengths. Two-fingered levers are now most popular and quite effective.
*Brake Cables The tension (and braking pressure) can be adjusted with a hex wrench near the wheel. A fine tuning can be done at the handlebar barrel adjuster.
*Brake Springs These a located near the brake pads. They can be adjusted, and sometimes removing the wheel will cause the spring to come loose.
*Braze-ons These are attached to frame for minor items such as brake pivots, cable anchors, for installing a rack, a water bottle cage, etc. . .
*Cables There are front and rear brake cables, and front and rear derailleur cables. They run thru cable guides.
*Chain Features here are proper length, maintenance, and quality. One of the most important features of your drivetrain. They are 1/2X3/32 in. but come in narrow, hyperglide, etc.. If you have a nine sprocket (27 speed) rear cassette, you should not use a narrow chain, but may require a special chain designed for 27 speeds.
*Chain Line The chain line should be such that the chain is totally straight and not torqued laterally when set on the middle chainring and middle sprocket in the rear. This will optimize shifting and prevent chain damage. Corrections to the chainline are made at the bottom bracket by inserting spacers, by straightening a bent frame, or repositioning the rear wheel in the dropouts.
*Chainrings Also called chainwheels or sprockets, these are the rings with teeth that engage the front of the chain near the crank arms. Usually you have three. The smallest is called the "granny gear" as it is the easiest to pedal. The largest is for top speed, and also is contacted during log hopping and occasionally on rocks. The size of the large chainring can affect the ground clearance. A good quality large chainring is mandatory for rough trails and rocks and logs (trust me - I know). One that bends should be replaced and upgraded. You can select different rings with different numbers of teeeth to alter your gearing.
*Chainstays Two of these; they are the tubes leading from the bottom bracket to the rear hub axle. They are part of the frame and have the dropouts that hold your rear wheel in place.
*Clipless Pedals These pedals rely on spring-loaded clips to grip the riders shoe without the use of toe clips or straps. They require a matching shoe and may require adjustment from time to time.
*Cone A threaded, conical nut that serves to hold a set of bearings in place and also provides a smooth surface upon which those bearings can roll.
*Crankarm The lever attached at the bottom bracket spindle used to transmit the riders energy to the chain. This is the piece that connects the pedal to the crank, or bottom bracket.
*Crankset This assembly includes the bottom bracket, two crank arms, the chainring set (usually three), and all the nuts and bolts.
*Derailleur There is a front and a rear derailleur on your bike. The front one moves the chain on the front chainrings. The rear one moves the chain on the rear freewheel. They work in conjunction with your shifters.
*Derailleur Hanger This is an extension of the right rear drop out, end it holds the rear derailleur in position. It can bend or break, and is fairly easy to replace.
*Disc Brake A disc brake stops the bike by squeezing brake pads against a circular disk attached to the wheel. They can be mechanical or hydraulic.
*Down Tube This is the tube that connects the head tubeand the bottom bracket together. It is the tube that your seatpost fits into, and is sometimes used in the measurement of your bike size.
*Drivetrain The drivetrain is made up of the crank arms, chain rings, bottom bracket, front derailleur, chain, your rear derailleur and free wheel or cassette.
*Dropouts The dropouts are the slots in the forks and the rear triangle where the wheel axles attach.
*Ferrule This is a cap for the end of a cable housing, for example on your brake cable.
*Forks The part that attaches a front wheel to the frame. It can be rigid, or a suspension fork. There are several types of a suspension forks, including elastomer, air oil, or SID's (all air).
*Frame This is the main part of the bicycle to which all other parts attach. Frames can be made out of a wide variety of materials, including aluminum, titanium, or chrome moly.
Freewheel This is the rear cluster of Cogs which are attached to the rear wheel through the freehub body.These are the rear gears in the back of the bike.
*Grip shift This is a shifter that is built into the handlebar grip. You can shift gears by twisting the grip. There are other types of shifters available, such as rapidfire thumb shifters, or the type that sits on top of the handlebars.
*Headset This is the part that holds the fork to the frame and allows the fork to turn in the frame. It usually consists of a cup, a lock ring, and bearings.
*Head tube The front tube of the frame through which the steering tube of the fork passes. The head tube is attached to the top tube and down tube and locates the headset.
*Hub This is the central part of a wheel to which the spokes are anchored and through which the wheel axle passes. Also includes the hub bearings located inside.
*Index shifter This is a shift or that collects into fixed positions as it moves from gear to gear. Most bikes have this feature.
*Jockey wheel A circular cog shaped pulley attached to the rear derailleur. There are two of them, and the chain runs over them. They are used to guide the chain, and move the chain laterally from cog to cog.
*Lockring This is the outer ring that tightens the adjustable cup of the bottom bracket against the face of the bottom bracket shell.
*Nipple Part of the spoke which is a small nut designed to receive the end of the spoke and fit the holes in the rim.
*Pedals These attach to the crankarms, have sealed bearings inside, and are where you place your foot to ride. They may be clip-less, platform, BMX, and made of plastic or metal.
*Presta valve A type of valve located on your tire where you put in the air. A Presta valve is the skinny type, and has to be loosened by hand before the air is put in.
*Quick release A tightening lever and shaft used to attach a wheel to the fork or rear dropouts without using axel nuts. It can also be used to secure the seat post in the down tube. It allows for a quick removal of the wheel, and an easy adjustment of your seat height.
*Rear triangle The we are portion of the bicycle frame, including the seat stays, the chain stays and this seat tube.
*Rims The outer hoop of a wheel to which the tire is attached.
*Saddle This is just another name for your seat. Made out of vinyl or leather, it attaches to the seat post.
*Schrader valve Another style of valve located on your tire to allow inflation. This is the same type of valve that car tires have. It may also be located on the components of an air suspension bike, for example, the front or rear shocks.
*Seatpost The post to which the saddle is attached. The seat post fits into the downtube, and usually has a quick release lever for adjustments. Some seat posts have a built-in shock absorber.
*Skewer A hub quick release or a shaft passing through a stack of elastomer bumpers in a suspension fork.
*Spokes Metal rods that connect to hub to the rim of a wheel. These come in many different shapes and sizes, and sometimes can be difficult to match up.
*Sprocket This is a circular, multiple toothed piece of metal that engages a chain. Also called a cog, freewheel, or chainring.
*Steering tube The vertical tube or on a fork that is attached to the fork crown and fits inside the head tube.
*Stem This component attaches the handlebar to the headset, and is made in various lengths.
*Swingarn The movable rear end of a rear suspension frame.
*Top tube The part of the frame that connects the seat tube to the head tube. This defines the length of the bike.
*V-brake A cable operated rim brake consisting of two vertical break arms with a cable link and cable guide pipe on one arm and a cable anchor on the opposite arm. An update to the U-brake system.
*Wheel base The horizontal distance between the two wheel axles.