Bike Components Buying Guide
Here is all about components...
Mountain bikes come with two types of brakes, the traditional rim brake, and disc brakes, which act very much like a car brake by grabbing on to the center of the wheel. The benefit of disk brakes is they are not affected by wet & muddy conditions, and they don't wear out the rims.
Road bikes usually have the standard caliper brake, although a few models are offering disc brakes.
Wheels and Tires
Tire width determines how much air it holds, and has an effect on how a bike handles. Thinner tires are best for fast time trials and lighter riders. Thicker tires are best for touring/commuting and heavier riders. Tires are referred by size of diameter (700c - measured in millimeters) x width size of 20, 23, 25 or 28. Most riders will use a 700c x 23 tire.
Today's wheels are lighter, more durable, more aerodynamic and are more attractive then ever before. Lighter wheels result in better acceleration, handling and climbing speed. Traditional wheel rims come with 32 spokes, and come in many designs based on style of riding.
Chainrings and Cogs
Your bike basically has two sets of sprockets. The one on the front, attached to the crankset, is called a chainring and is either a "double" (has 2 chainrings) or "triple"(adds 3rd chainring for easier gears to climb hills). The one on the back, attached to the rear wheel, is called a cassette(or group of cogs).
To determine how many gears your bike comes with, you multiply the number of the chainrings times the number of cogs on your cassette. A double chainring with an 8-cog cassette results in 16 gears.
Chainrings and cogs are named by the number of teeth on them. A double chainring may be referred to as 39/53, which means the smaller chainring has 39 teeth and the larger chainring has 53 teeth. A triple just adds another chainring with lesser teeth, usually giving you a 32/42/52 set-up. Cogs are normally referred to as a range of teeth, from smallest to largest. A 12-23 cassette, means the smallest cog has 12 teeth and the largest cog has 23 teeth.
Basically, this means the range of ease you can ride with all of your gears. For chainrings, the higher the number, the harder it is to pedal. For cogs, the lower the number, the harder it is to pedal. Just the opposite. For example, let's say you have a 39/53 chainring with a 12-23 cassette. The highest possible gear to ride in (the hardest) is 53 chainring and 12 cog. The lowest gear to ride in (the easiest) is 39 chainring and 23 cog.
If you ride long distances, live in a hilly area, travel to different destinations or might not be at a high level of fitness, we would recommend a triple-chainring. It just offers you more choices in gears, allowing you to drop to a very easy/low gear ratio. Most competitive riders go with a double chainring, saving them some weight on the bike. If you elect to go with a double, but worry you might not have a low enough gear for difficult hills, you can package your bike with smaller chainrings and larger rear cassette.
The best way to digest all of this information is to go to the leading bicycle manufacturers websites and look at their products. Now that you are loaded with information, you can make a better buying decision!