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 usually 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 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.