Bike Jargon Buster :: Bicycle Components

The bike components are what are fitted to it to make it go and stop - and make it comfortable for you. There’s a huge choice available, but there are some basic guidelines:

Wheels:

Alloy Wheels: 
All good bikes will have aluminium alloy wheel rims - they are lighter, don’t rust, and the brakes work much more efficiently than with steel rims.

Stainless Steel Spokes: 
A mark of quality. Stainless steel spokes are not really any lighter than the cheaper galvanised ones, but they do look better and don’t rust.

Double-butted Spokes: 
Like double-butted tubing, these are thinner in the middle where the extra metal is not needed. They are lighter, and funnily enough they are actually stronger than the normal ones (called “straight gauge”).

Gears:

Derailleur Gears: 
Derailleur gears work by having several cogs at the front and back of different sizes, and use a cage mechanism (the derailleur) to “derail” the chain from one cog to another. It sounds unsophisticated and it is, but it is light and works surprisingly well. Derailleur systems are exposed to the elements so need a reasonable amount of maintenance. They can have 15, 18, 21, 24 or 27 gears, although there is quite a bit of overlap in the ratios.

Hub Gears: 
Hub gears have a gearbox built in to the rear hub, sealed away from the elements. Gears are engaged and disengaged by a pushrod from the end of the hub. Hub gears are heavier than derailleurs, but need a lot less maintenance, and are more forgiving of misuse. They can have 3, 4, 5, 7 or 14 ratios, with no overlap between them.

Gear Shifters: 
Gear shifters are the controls on the handlebars which you use to change gear. Nowadays, almost all of them are indexed - this means they click into gear and you don’t have to guess how far to move them. They come in three basic types:
Thumbshifters - These are simple levers sitting on top of the handlebars - push them one way to go up a gear, push the other way to go down.
Pushbutton shifters - ("STI") These use two buttons or levers, usually one for your thumb and one for your index finger. Push with your thumb to go up a gear, push with your index finger to go down.
Twist shifters - ("Gripshift", "Revoshift") With these, you twist a section of the handlebar grip to change gear.

Brakes:

Rim-mounted Brakes: 
These are brakes which work by squeezing the wheel rim. There are two main types:
V-type or Cantilever - These have two arms fitted to the frame or fork, pulled together by a cable strung between them. V-types have long arms and one cable which pulls across the top of the tyre. Cantilevers have shorter arms and a Y-shaped cable which pulls upwards. Both types are very powerful, and are found on mountain bikes and many others.
Calliper - These are like pincers - pulling the cable makes them clamp onto the rim. They are not as powerful as V-type or Cantilever, but the new “Dual Pivot” ones come very close. Callipers are mainly found on racing bikes.
All rim brakes have the advantage of being light, but can have problems in poor conditions - because the rim gets very close to the road it can get clogged up with mud or water, making the brakes less powerful.

Hub-mounted Brakes: 
These work at the hub, not the rim, and fall into two types:
Disc - These have an exposed steel disc at the hub, which is clamped by a small calliper. Discs can be very powerful, and are also pretty light. They are exposed to the elements, but because they are further from the road they are less affected by mud and water. Discs are popular on mountain bikes because they are so powerful.
Drum (a.k.a Hub) - These have a sealed drum at the hub, with two expanding brake shoes inside it. They are not quite as powerful as discs, but are completely sealed against the elements. They are heavier than other types of brake, and are often used on city bikes because of their very low maintenance.

Hydraulic Brakes: 
Most brakes are operated by pulling a steel cable, but hydraulic brakes work more like that of a car, using pistons to compress oil which then transmits the force. Hydraulics have lower maintenance than cables as they are sealed - cables can get gummed up with mud or rust. They are also very powerful, as they multiply the force of your hand. Hydraulics are available to operate on the rim (like cantilevers) or as disc brakes. Hydraulics are more expensive than cable-operated brakes, and require expert treatment if they go wrong.

Other Parts:

Other parts include the saddle, handlebars, stem, etc. The basic guideline here is to go for aluminium over steel when at all possible - it is lighter and does not rust. The exception is with saddles, which are only made in steel, magnesium or titanium (if you’re rich!).