Before you build or buy a downhill bike, you must know something abut the way these bikes are built and how they work. These are not like your ordinary bicycles and being aware of the facts will help you ride these mountain bikes better.
These mountain bikes have full suspension. As their name implies, they are constructed for cycling downhill, particularly on rough, steep and sharp terrains and trails.
For this reason, the bikes are built with stability and durability in mind. These are much heavier than your typical cross-country bicycle. Bikes built for downhill cycling can perform a quick descent.
The bikes are usually made of steel or aluminum. The suspension travel ranges from 180 – 250 mm (7 to 10 niches). The suspension fork is about 180 – 203 mm (7 to 8 inches). The suspension lag is higher than ordinary bicycles (about 25%-50% of total travel).
These mountain bikes also have slack head tube angles. It usually maxes out at 66 degrees, and often much less than that. Very often it will accommodate the use of 3 inch wide knobbed tires.
The downhill frames are also made to cope with the pressure of riding difficult terrain. These bike frames are designed to cope with jumps, drops and bumpy terrain.
The old downhill bikes usually weigh 18 kg (40 lbs). The newer models weigh in around 45 lbs. There are also bikes that weigh 50 lbs. However there are also lighter bikes being developed, with some weighing less than 38 lbs.
Most of these bikes have long wheelbases, up to 45 inches or so. The disc brakes will measure 203 mm (8 inches). These bikes also have a chain guide so chain derailment does not happen. The OnePointFive head tube standard has a 1.5″ wide head tube.
By contrast the head tube used in conventional bikes is 1.125″ in diameter. The reason for the change is to give the bike more strength and make it stiffer. There are also adjustable head tube angles. This allows the biker to make adjustments.
In terms of frame and long travel, these bikes are a lot like freeride bikes. Numerous models make use of triple clamp forks. This permits longer travel time up front (about 203 mm / 8 in).
This gives the bike a stiffness that single crown forks cannot match. However, this does reduce the turning circle and increases the weight.
How to Adjust the Bike for Downhill Racing
The first thing you have to do is lower the seat as much as possible. It also helps if the stem is shorter. The shorter the stem is, the easier it will be to ride downhill. You will also have to get tires that resist flats and allow for more traction. Make sure the chains are stable too.
A downhill bike is the best option for riding on rocky terrains and uneven surfaces. The manner in which it is built makes it suitable just for this kind of work. By knowing the basic features of the bike, you will know what to look for when you buy.