| Bike trials is a form of mountain biking derived from | | | | over the years have become very specialized. There |
| motorcycle trials where one slowly negotiates | | | | are two types of trial bikes in competition classes, the |
| man-made and natural obstacles. It originated in Spain | | | | 20A" or mod and the 26A" or stock. There are also a |
| and is said to have been invented by Ot Pi's father (A | | | | few 24A" trials bikes, though these are deemed illegal |
| world champion motorcycle trials rider) who wanted | | | | are not allowed to be used in most competition circuits. |
| his son to learn and practice motorcycle trials on an | | | | All trial bikes have powerful brakes (usually disc or |
| ordinary push bike instead of a motorbike as it is hard | | | | hydraulic rim brakes) in order for the rider to have |
| for small children to control motorcycle trials bikes. | | | | maximum control over the bike. Grip is very important |
| At the most basic level, trials riding can be summed up | | | | so wide tyres (2.2A-2.7A") with soft, sticky rubber |
| as bicycle handling skills. It evolved from motorcycle | | | | compounds are run on wide rims (32A-47mm), to help |
| trial riding (riding up, over obstacles, man-made or | | | | spread the tyre contact patch permitting lower tyre |
| natural) into an off-season bicycle pastime. It now has | | | | pressures (10A-25psi) to be used without the risk of |
| a strong A- though small A- following, and can be seen | | | | tyre rolling off the rim. Gear ratios are also low to allow |
| worldwide. Skills taken from trials riding can be used | | | | the rider maximum power and quick acceleration of |
| practically on any bicycle for balance, for example | | | | the bike at the typically low speeds of trials riding. |
| controlled braking and track standing, or balancing on | | | | Mods usually have an 18-tooth sprocket and a 12-tooth |
| the bike without putting a foot down. Trial bike | | | | rear cog whilst stocks vary from 22/19 all the way |
| characteristics include, but are not limited to: powerful | | | | down to 18/12. |
| brakes, wide handlebars, light parts, low gearing and a | | | | 20A" A- 'modified' |
| heavy emphasis on frame geometry. | | | | The 20A" variety of trials bike (known as a modified |
| It is completely different from individual time trial races, | | | | or mod bike) is a small, short trials bike with a 20A" |
| which are an element of road bicycle racing. | | | | front wheel and a 19A" rear rim, consisting of only one |
| Rulings | | | | gear, a bash guard to protect the frame from any |
| The general principle in a bike trials competition is to | | | | damage and to grip onto objects, and a large rear tire |
| ride a number of pre-marked sections (usually 2 laps | | | | (2.5A-3.0A") similar to a trials motorcycle rear tire. The |
| of 10 sections or 3 laps of 7 sections), the winner being | | | | term 'mod' comes from the fact that the frames were |
| the rider with the least points at the end of the | | | | originally modified BMX frames, now used for trials. |
| competition. | | | | 26A" A- 'stock' |
| The maximum number of points that can be obtained | | | | The 26A" variety of trials bike (known as a stock bike) |
| in each section is 5, the lowest (and best) score is 0 | | | | was originally derived from a normal mountain bike |
| points or 'clean'. The most common way to gain a | | | | kept in original condition. Now, however, this designation |
| point is by putting a foot down within a section; for this | | | | is often used to describe any trials bike with 26" |
| reason points are sometimes known as 'dabs'. Certain | | | | wheels. Many modern competition stock trials bikes |
| rules enforce the number of points gained within a | | | | lack a standard bicycle seat and seatpost. During |
| section, for example, putting both feet down will result | | | | competition the rider has no need for these, and the |
| in 5 points. Exceeding the time limit for the course will | | | | omission of them allows for a lighter bike which |
| either result in 5 points (BIU rules) or an additional point | | | | interferes less with the body movements of the rider. |
| for every 15 seconds over the limit (UCI rules). | | | | 26A" 'comp' (competition) |
| Types of bike trial Competitions | | | | These bikes have a higher bottom bracket |
| Currently there are two regulated types of competition | | | | (330A-420mm) to increase bash ring clearance, short |
| ruling, enforced by the UCI and BikeTrial International | | | | chain stays (365A-385mm), a long wheelbase |
| Union. | | | | (1050A-1115mm) and normal head angles (70A-72o). |
| UCI | | | | This geometry eases balancing on the back wheel, |
| Within UCI ruling, if any part of the bike except the | | | | gapping (jumping on the back wheel) from one |
| tyres touch any object in the course, a dab will be | | | | obstacle to the next and side-hopping (jumping up with |
| given. The UCI rules were changed to this format after | | | | the bike parallel to an object). |
| too many competitions ended in a draw and riders | | | | 26A" 'street' |
| were forced to ride an extra section. UCI rules also | | | | These bikes tend to have a shorter wheelbase |
| allows riders to compete in both mod and stock | | | | (1000A-1050mm), steeper head angles (72A-74o), |
| categories. | | | | zero-drop bottom brackets and seats. They are |
| When a rider is in a section, neither tyre is allowed to | | | | typically used for street style trials or smaller riders, |
| cross the side boundary tape even if the wheel is in | | | | and the bikes are not as specialized. This geometry A- |
| the air. The rider's hands must remain on the | | | | which is similar to BMX geometry A- makes the bike |
| handlebars. Riders in the 26A" class must also have | | | | easier to bunny-hop (jump over an obstacle at speed) |
| six working gears. | | | | and manual (roll on the rear wheel whilst the front |
| The UCI Mountain Bike & Trials World Championships | | | | wheel is held up), and the increased head angle makes |
| are held annually and crown a 20-inch and 26-inch | | | | it easier to move the bike around whilst on the front |
| wheel trials world champion. | | | | wheel. These bikes tend to appear more along the |
| BIU | | | | lines of a mountain bike than the natural or competition |
| The rules are unlike UCI scoring and parts of the bike | | | | 26A" bikes even if geometry-wise they are not. |
| (for example, bash guard or bash ring, cranks and | | | | Due to the recent surge of street riding, particularly in |
| pedals) can rest on an object without resulting in a | | | | the UK, there are now several brands almost |
| 'dab'. The level of riding for the elite 20A" class is | | | | exclusively for street riding. These bikes are legal to |
| regarded as the highest in bicycle racing since the | | | | enter in most competitions due to the wheel size but |
| section beginner is set at the highest technical level. | | | | are also not very suited for natural riding in comparison |
| Bike types | | | | to comp bikes or mods mainly because of their overly |
| Trials bikes are no longer standard mountain bikes, but | | | | steep head angles. |