Bike trials riding
From Wikipedia, the free encyclopedia
Bike trials is a form of mountain biking derived from motorcycle trials. The rider slowly negotiates man-made and natural obstacles. It originated in Spain and is said to have been invented by Ot Pi’s father (a world champion motorcycle trials rider). As it is hard for small children to control motorcycle trials bikes, he had wanted his son to learn and to practice motorcycle trials on an ordinary push bike instead of a motorbike.
At the most basic level, trials riding can be summed up as bicycle handling skills. It evolved from motorcycle trial riding (riding up, over obstacles, man-made or natural) into an off-season bicycle pastime. It now has a strong — though small — following, and can be seen worldwide. 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. Trial bike characteristics include, but are not limited to: powerful brakes, wide handlebars, light parts, low gearing and a heavy emphasis on frame geometry.
It is completely different from individual time trial races, which are an element of road bicycle racing.
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[edit] Rulings
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 least points at the end of the competition.
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 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).
[edit] Types of bike trial Competitions
Currently there are two regulated types of competition ruling, enforced by the UCI and BikeTrial International Union.
[edit] UCI
Within UCI ruling, if any part of the bike except the tyres 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 tyre 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. Riders in the 26″ class must also have six working gears.
The UCI Mountain Bike & Trials World Championships are held annually and crown a 20-inch and 26-inch wheel trials world champion.
[edit] BIU
The rules are unlike UCI scoring and parts of the bike (for example, bash guard or bash ring, cranks and pedals) can rest on an object without resulting in a ‘dab’. The level of riding for the elite 20″ class is regarded as the highest in bicycle racing since the section beginner is set at the highest technical level.
[edit] Bike types
Trials bikes are no longer standard mountain bikes, but over the years have become very specialized. There are two types of trial bikes in competition classes, the 20″ or mod and the 26″ or stock. There are also a few 24″ trials bikes, though these are deemed illegal are not allowed to be used in most competition circuits. All trial bikes have powerful brakes (usually disc or hydraulic rim brakes) in order for the rider to have maximum control over the bike. Grip is very important so wide tyres (2.2–2.7″) with soft, sticky rubber compounds are run on wide rims (32–47mm), to help spread the tyre contact patch permitting lower tyre pressures (10–25psi) to be used without the risk of tyre rolling off the rim. Gear ratios are also low to allow the rider maximum power and quick acceleration of the bike at the typically low speeds of trials riding. Mods usually have an 18-tooth sprocket and a 12-tooth rear cog whilst stocks vary from 22/19 all the way down to 18/12.
[edit] 20″ — ‘modified’
The 20″ variety of trials bike (known as a modified or mod bike) is a small, short trials bike with a 20″ front wheel and a 19″ rear rim, consisting of only one gear, a bash guard to protect the frame from any damage and to grip onto objects, and a large rear tire (2.5–3.0″) similar to a trials motorcycle rear tire. The term ‘mod’ comes from the fact that the frames were originally modified BMX frames, now used for trials. These where also the first type of training bikes for mototrials riders.
[edit] 26″ — ‘stock’
The 26″ variety of trials bike (known as a stock bike) was originally derived from a normal mountain bike kept in original condition. Now, however, this designation is often used to describe any trials bike with 26" wheels. Many modern competition stock trials bikes lack a standard bicycle seat and seatpost. During competition the rider has no need for these, and the omission of them allows for a lighter bike which interferes less with the body movements of the rider.
[edit] 26″ ‘comp’ (competition)
These bikes have a higher bottom bracket (330–420mm) to increase bash ring clearance, short chain stays (365–385mm), a long wheelbase (1050–1115mm) and normal head angles (70–72º). This geometry eases balancing on the back wheel, gapping (jumping on the back wheel) from one obstacle to the next and side-hopping (jumping up with the bike parallel to an object).
[edit] 26″ ‘street’
These bikes tend to have a shorter wheelbase (1000–1050mm), steeper head angles (72–74º), zero-drop bottom brackets and seats. They are typically used for street style trials or smaller riders, and the bikes are not as specialized. This geometry — which is similar to BMX geometry — makes the bike easier to bunny-hop (jump over an obstacle at speed) and manual (roll on the rear wheel whilst the front wheel is held up), and the increased head angle makes it easier to move the bike around whilst on the front wheel. These bikes tend to appear more along the lines of a mountain bike than the natural or competition 26″ bikes even if geometry-wise they are not.
Due to the recent surge of street riding, particularly in the UK, there are now several brands almost exclusively for street riding. These bikes are legal to enter in most competitions due to the wheel size but are also not very suited for natural riding in comparison to comp bikes or mods mainly because of their overly steep head angles.
[edit] External links
- BikeTrials.com — a trials resource with how-to's, competition coverage, and product reviews
- trials-forum — a trials community based in the uk
- BikeTrials.ca — official website of BikeTrial in the Canada
- BikeTrial UK — official website of BikeTrial in the UK
- TrashZen.com — Illustrated tutorials to learn all the techniques of trials riding
- bike-trial.net - A trials community based in Norway
- Essex Street Trials - A trials community based in Essex
- Observedtrials.net - informative US based trials forum
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