| Your bicycle's drivetrain is comprised of all of the | | | | thread and the left cup having a regular thread. |
| parts that power the bicycle and make it go. Bike | | | | Chain |
| pedals move the cranks, which turn the bottom | | | | The chain connects the chainring to the rear |
| bracket and the chainrings, which drive the chain that | | | | sprocket, transmitting power from the rider to the |
| spins the rear sprockets, turning the rear hub, which | | | | rear wheel. Current bicycles use roller chains (with |
| moves the wheel and propels the bicycle forward. | | | | few exceptions) that are categorized by pitch and |
| The crisp movement of these parts and the ability to | | | | width. The chain's pitch is the distance from roller to |
| minimize effort while maximizing speed is the heart of | | | | roller and is typically 1/2 inch on modern bicycles. The |
| cycling. It is essential that drivetrain be clean, true and | | | | width is measured between chain plates and is either |
| well-maintained in order to more fully enjoy riding | | | | 1/8 inch for derailleur-less bikes and 3/32 inch for |
| your bike. When one of these parts gets out of | | | | multi-speed, derailed bikes. |
| whack, the rest soon follow. | | | | Another specification of a bicycle chain is based on |
| It is also important to get individual components that | | | | outer width: the outside distance between chain-link |
| are compatible within the system (e.g. typically | | | | plates. There are two main standards: Campagnolo |
| Campagnolo and Shimano parts are not | | | | and Shimano. Shimano uses the same width chain for |
| inter-compatible). Many times the difference between | | | | all drive trains with eight or fewer gears in the rear |
| 9- and 10-speed parts is enough to make them | | | | cassette or freewheel and a different width each for |
| incompatible as well. The collective term for a | | | | its 9- and 10-speed groups. Campagnolo uses three |
| complete bike drivetrain kit is "group" or "gruppo." | | | | widths presently: 9, 10 and 11. As the number of |
| Multi-speed drivetrains are classified by the number of | | | | sprockets in the rear increase, the width of the chain |
| cogs in the rear cassette. A modern day 10-speed | | | | must decrease, providing enough clearance for the |
| bicycle can have as many as 30 "possible gears," with | | | | extra gears. Other companies manufacture chains |
| 10 in the rear and three in the front, but still have a | | | | that are designed to work with the Campy and |
| 10-speed drivetrain. | | | | Shimano systems. |
| Pedals | | | | Derailleurs |
| Your bike pedals are your power connection to your | | | | On multi-speed bicycles, the derailleur moves the |
| bicycle. As you pump your legs and turn your feet, | | | | chain from one sprocket to another. They are |
| you cause the cranks to turn. Proper pedal choice is | | | | actuated by a cable pulled from the shifters, typically |
| important for comfort, control and safety on the | | | | mounted onto the handlebars (and sometimes down |
| bike. Many recreational and enthusiast cyclists prefer | | | | tubes) of the bicycle. |
| the adaptability that platform pedals offer. They | | | | Front derailleur |
| allow you to ride in any type of shoe and give a | | | | The front derailleur moves the chain from chainring to |
| sense of security to a novice rider who is cautious of | | | | chainring and acts as a chain guide, keeping the chain |
| locking the feet into clipless pedals. Many platform | | | | aligned. There are several chainring characteristics to |
| pedals can be adapted with a toe cage to give more | | | | consider when shopping for a front derailleur. The |
| control and power while retaining the sense of | | | | most important is double or triple (whether there are |
| security associated with platforms. | | | | two or three chainrings attached to the crank). A |
| Racers and more advanced riders often prefer | | | | triple front derailleur is designed with a deeper inner |
| "clipless" pedals. These pedals are used in conjunction | | | | cage than a double derailleur to be able to push the |
| with matching cleats that are attached to special | | | | chain up from the small ring. |
| shoes. The cleats lock into place in the pedal, offering | | | | Another key characteristic is chainring size. Certain |
| a secure attachment of rider to bicycle. Most cleats | | | | derailleurs' cage diameters limit the maximum number |
| easily release the shoe by a simple twist of the | | | | of teeth possible on the large ring. The final |
| ankle, and they are quite easy to use with some | | | | characteristic is 8/9/10-speed compatibility. The width |
| initial practice. | | | | between the inner and outer cage varies between |
| Cranks | | | | designs and may not work well when used with the |
| The cranks connect the pedals to the bottom | | | | wrong gearing. |
| bracket and hold the front chainrings. They connect | | | | Rear derailleur The rear derailleur acts as a chain |
| to the axis around which your feet spin and transmit | | | | guide and chain tensioner. As the chain moves from a |
| your power to the bike. Cranksets come in many | | | | large sprocket to a smaller one, it needs less chain to |
| different lengths based upon bicycle frame size and | | | | cover the circumference. The rear derailleur has a |
| the rider's leg length. They are generally made out of | | | | spring mechanism that pulls in that extra length of |
| aluminum, but some low-end cranks are made of | | | | chain, known as "chain wrap." The rear derailleur also |
| steel, and some high-end cranks are made of carbon | | | | moves the chain from cog to cog and is one of the |
| fiber. These cranksets are marketed to top-level | | | | more active components of the bicycle. As you pedal |
| racers and generally carry the appropriate price tag. | | | | and drive the chain around the chainrings and rear |
| Cranks attach to the bicycle at the bottom bracket. | | | | sprockets, the chain continuously runs through the |
| There are several types of cranks/bottom bracket | | | | rear derailleur. |
| interfaces, and it is important to know their | | | | Rear derailleurs are classified in the same manner as |
| differences. | | | | front derailleurs--first by speed: 8/9/10, then by |
| Chainrings | | | | double or triple (it is actually the difference between |
| Chainrings are the forward chain interface with the | | | | the largest and smallest chainring added to the |
| bicycle. They contain teeth that hold the chain and | | | | difference between your largest and smallest cog). |
| drive it forward. Chainrings come in a wide range of | | | | Typically, with a double chainring you can use a short |
| sizes, identified by the number of teeth and | | | | cage and with a triple you would need a long cage. |
| application. Typical mountain bikes use three | | | | The longer cage helps take up the extra slack that |
| chainrings; road bikes generally have two to three. | | | | appears when in the small ring. |
| Single-speed and fixed-gear bicycles use only one | | | | Rear sprocket |
| chainring. Chainrings are typically made of aluminum, | | | | The rear sprocket is the chain's rear interface with |
| with some being made of steel and a handful of | | | | the bicycle. On a single speed (fixed gear included) |
| boutique brands making them out of carbon fiber. | | | | you only use one rear sprocket, or cog. Multi-speed |
| What makes a proper chainring is dependent upon | | | | bikes have a cluster of cogs called "cassettes" or |
| many factors: number of teeth, single/double/triple | | | | "freewheels." |
| configuration, 8/9/10/11 speed use and bolt circle | | | | A freewheel is a group of cogs fixed to a |
| diameter. Once all of those factors have been | | | | "freewheel" mechanism that allows you to coast; |
| determined, you can choose the group level or brand | | | | there is a ratcheting mechanism that allows the rear |
| that best suits your needs. | | | | hub to spin as you coast, or ride without pedaling. A |
| Bottom bracket | | | | bike cassette is designed to be used with a rear hub |
| The bottom bracket is the cranks' interface with the | | | | equipped with a freewheel mechanism to which you |
| bike. It contains bearings around which an axle | | | | attach the cogs. |
| rotates; this axle is connected to the cranks. Current | | | | Typical freewheels come in 5- to 7-speed versions, |
| bottom brackets come in varying interface types. | | | | and cassettes are 8/9/10/11-speed, with few |
| Traditional bottom brackets have loose ball bearings | | | | exceptions. Cassette cogs are designed to be set up |
| with their accompanying cups and cones and an axle | | | | in a particular orientation to aid in shifting; any |
| locked in place with locknuts, typically on the left side | | | | variation of this orientation can cause serious shifting |
| of the BB shell. More recent cartridge bottom | | | | and safety issues. Cassettes are designed to be used |
| brackets are built as one piece with cartridge | | | | with the appropriate chain, and the wrong chain won't |
| bearings press-fit onto the axle and fit into the frame | | | | ride on the teeth properly, resulting in a very poor |
| with "cups" that thread into opposite sides of the | | | | and annoying ride. |
| shell. | | | | Rear hub |
| Many bike parts companies have most recently been | | | | The rear sprocket is attached to the hub directly (in |
| developing bottom brackets without an axle. The | | | | the case of a fixed gear), or via a freewheel |
| axle is built into the cranks and runs through bearings | | | | mechanism. The power from the front chainring is |
| that are press-fit into cups that thread into the | | | | transmitted via the chain to the rear sprocket and |
| bottom bracket shell. The other end of the axle then | | | | into the rear hub, the central point of the rear wheel. |
| attaches to the opposite crankarm. Different brands | | | | The two main characteristics of a rear hub are hub |
| have different bearing sizes and only work with their | | | | type (cassette, freewheel or fixed) and hub spacing |
| respective cranks. | | | | (the width from axle end to axle end). Modern road |
| Bottom brackets come in many different interfaces | | | | bikes are spaced to 130mm, mountain bikes to |
| developed by the different component | | | | 135mm and track bikes to 120mm. Older bicycles |
| manufacturers. Cup and cone BBs are generally | | | | were spaced to 126mm. They were typically |
| "square taper." Cartridge bottom brackets are one of | | | | designed for use with freewheel-type rear hubs that |
| two versions of square taper (International Standard | | | | carried fewer gears. |
| or Japanese Standard) or one of the many versions | | | | With the advent of the freewheel hub and more |
| of splined BB developed by the several companies. | | | | gears, the rear dropout spacing was increased to |
| Another important aspect of bottom bracket | | | | accommodate. Another thing to consider when |
| compatibility is whether your bicycle has an Italian or | | | | choosing a hub (if it is already built as part of a |
| English threaded bottom bracket. The shell diameter | | | | wheel) is the wheel diameter. The rim must be the |
| of an Italian bottom bracket is larger, threaded 36 | | | | appropriate size to fit into the frame and line up with |
| mm x 24 tpi, and its threads are both normal (or | | | | the brake pads. |
| right-handed). English bottom brackets are threaded | | | | I suggest Bike Wagon for bike parts. |
| 1.370-inch x 24tpi, with the right cup having a reverse | | | | |