You've heard of some nearby bike trails and now you're dreaming of off-road adventure. So what type of bicycle do you need? If you're just beginning, it is best to start small and work your way up, both in the investment of a bike and the level of terrain you wish to go cycling on.

Start with a budget. There's no sense buying a top of the line MTB (MounTain Bike), only to realize you either don't have the time or aren't as interested in off road biking as you thought. Talk to a sales clerk at a local bike shop, and try some models to get a feel for the ride. Larger department stores sell cheap bikes, but remember you get what you pay for, and you will not get the after-sales service that a local bike store will give you. Also, check your community newspaper for used bicycles.

No matter what the price, all mountain bikes have the following basic features. The difference between a $200 bike and one that sells for $3000 is the components, materials and add-ons, which we will illustrate:

Frame

A basic frame will be hollow aluminum or steel parts welded together. Perfectly round metal is equally strong on all sides, however, higher end bikes will be more oval, taller than they are wide. This is because most of the stress on a bike is up and down, not side to side. As you go up in price, the frame could be made of a combination of aluminum and carbon fiber, a lighter and stronger material that allows the manufacturer to build a frame in any shape.

Brakes

Most bicycles use cantilever or "v" brakes. Levers on the handlebars pull a cable. The cable is connected to a set of clamps with brake pads. The clamps tug to the rim of the bike wheel, stopping the bike. To perform best, the cables have to be well aligned and the rims have to be straight and free of dirt or water, which is often impossible in muddy terrains. The pads have to often be replaced, and your rims will wear down. However, they are a popular and reliable system.

A step up is disc breaks, which work just like those in your car. Introduced in the late 1990's, these use a hydraulic system to squeeze brake pads onto a disc situated in the inner part of the wheel. The performance does not suffer from dirt or water, they are much more reliable, and last longer than v brakes. However, besides the increased cost and complexity, they are also heavier.

Gears and derailleurs

Gears are used so the rider can move at a constant pace no matter what the terrain or slope. A bike with one gear is said to have a gear ratio of 1:1 (each time you pedal one revolution, the back wheel will rotate one revolution as well.) Usually you would wish to go faster than that, so gears are used to increase the speed of the back tire when you pedal. A comfortable gear ratio on a level highway is about 6.5:1. However, when you're going uphill, making the back wheel go that fast is impossible, so you would gear down towards a ratio of 1:1. Shift gears before you need to, as you need the chain moving smoothly to shift.

A derailleur is a device to switch the gears, controlled by shifters attached to the handlebars. A cable moves a spring, which forces the chain onto another sprocket (the cogs on the back wheel and between your pedals).

Suspension

The suspension gives the biker comfort, absorbing bumps and potholes similar to that of a vehicle. Styles range from no suspension (hardtail), to full suspension (front and rear). While suspension systems add weight to the bike, the trade off is better comfort and enjoyment. Many inexpensive, entry-level mountain bikes now come with full suspension, though hardtails are definitely less expensive. Higher-end suspension systems will deliver more shock absorbency and durability with less weight.

These features will help you decide what to look for in a mountain bike. To save even more money, look for special deals in the spring and fall. Once you have the right bike, you are on your way to enjoying yourself on the trails.