Mountain bike trials

Mountain bike trials, also known as observed trials, is a discipline of mountain biking in which the rider attempts to pass through an obstacle course without setting foot to ground. Derived from motorcycle trials, it originated in Catalonia, Spain and is said to have been invented by the father of Ot Pi, a world champion motorcycle trials rider. Pi's father had wanted his son to learn motorcycle trials by practicing on an ordinary bicycle.

Trials riding is an extreme test of bicycle handling skills, over all kinds of obstacles, both natural and man-made. It now has a strong – though small – following worldwide, though it is still primarily a European sport. Skills taken from trials riding can be used practically on any bicycle for balance, for example controlled braking and track standing, or balancing on the bike without putting a foot down. Competition trial bikes are characterized by powerful brakes, wide handlebars, lightweight parts, single-speed low gearing, low tire pressures with a thick rear tire, distinctive frame geometry, and no seat.

The general principle in a bike trials competition is to ride a number of pre-marked sections (usually 2 laps of 10 sections or 3 laps of 7 sections), the winner being the rider with the fewest points at the end of the competition.

Currently there are two official types of competition rules, enforced by the UCI and BikeTrial International Union.

The maximum number of points that can be obtained in each section is 5, the lowest (and best) score is 0 points or 'clean'. The most common way to gain a point is by putting a foot down within a section; for this reason points are sometimes known as 'dabs'. Certain rules enforce the number of points gained within a section, for example, putting both feet down or a hand will result in 5 points. Exceeding the time limit for the course will either result in 5 points (BIU rules) or an additional point for every 15 seconds over the limit (UCI rules).

Within UCI rules, if any part of the bike except the tires touch any object in the course, a dab will be given. The UCI rules were changed to this format after too many competitions ended in a draw and riders were forced to ride an extra section. UCI rules also allows riders to compete in both mod and stock categories.

When a rider is in a section, neither tire is allowed to cross the side boundary tape even if the wheel is in the air. The rider's hands must remain on the handlebars. Before beginning a section, a rider is allowed to walk through it, and examine all the elements, but must not enter it with their bike.

The UCI Mountain Bike & Trials World Championships are held annually and crown a 20-inch and 26-inch wheel trials world champion.

Trials bikes are often designed without regard for attaching a seat. Competition riding does not require the rider to sit down and the omission allows for a lighter bike which interferes less with the body movements of the rider. Brakes must be more powerful than standard bicycle brakes in order to prevent the wheel from moving when hopping on uneven surfaces. Tires and rims are wide allowing low pressures and increased contact and grip. Gear ratios are lower than on most bicycles in order to provide the power and quick acceleration needed to move the bike at the typically low speeds of trials riding.

According to current competition standards there are two classes of trials bike recognized. As the distinguishing characteristic of the classes is the bike's approximate wheel diameter, the classes are known as 20″ and 26″. These specific sizes were adopted from previously available bikes.

Trial riding requires very good brake control, and as a result, bicycle trials riders sometimes have unusual brakes. On the front wheel, good brake modulation is usually the goal, whereas in the rear, maximum braking power is more important. In the rear, riders will often run special hydraulic rim brakes with frame stiffeners called brake boosters, and they sometimes grind their rims to create a rough surface and even put roofing tar on their rims to make them sticky. Disc brakes are also common. UCI regulations only stipulate that the bike must have a working front and rear brake.

UCI regulations stipulate that a course consist of at least 14 sections per course, including repeated sections. At most two sections can be composed entirely of artificial elements. Both sides of the course are marked with plastic tape, and there must be a clear stretch of 3 metres prior to the finish line, in order to prevent riders jumping over the line from an obstacle. Maximum obstacle jump heights are specified, from 0.80 to 1.80 metres depending on category. The sections, each approximately 60m in length, are laid out on a circuit to allow riders to ride from one section to the next, but whether the sections have to be completed in order depends on the individual competition.