| Biking around a Mountain |
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Mountainbikes - typically - have 3 chainrings (front) and either 7, 8 or 9 speed cassettes (rear). 10-speed rear cassettes (as found in road cycling) would require a chain that’s too slim & simply not strong enough for mountainbiking. Mountain bikes are synonymous with disc brakes, and the potential cost, weight & maintenance disadvantages of them are completely outweighed by the massive increase in stopping power and their ability to remain cleaner for longer, being centred on the wheel’s hub. Relatively speaking, of course! Most mountain bikes use 26-inch (559 mm) wheels, though some models offer 24 or 29-inch (520 or 622 mm) wheels. Bicycle wheel sizes are not precise measurements, a 29-inch mountain bike wheel actually has a 622 mm (24.48 inch) bead seat diameter, and confusingly, 622 mm wheels are standard on road bikes but commonly known as 700c. (In Europe 700c (622 mm) wheels are commonly called 28-inch wheels!) 24-inch wheels are used for dirt jumping bikes and sometimes on Freeride bikes’ rear wheels, as it tends to make the bike more manoeuvrable. 29-inch wheels were mainly used for Cross-Country purposes, but are becoming more commonplace in other disciplines of mountain biking. Wheels come in a variety of widths, ranging from 1.9 in to 3.00 (such extreme widths are popular with Freeride and Downhill bicycles). Manufacturers produce a wide variety of tyre tread patterns to suit different needs, with patterns ranging from slick street tyres, street tyres with a centre ridge and outer tread, fully knobbly, front-specific, rear-specific, and snow studded. Tyres and rims are available in either tubed or tubeless designs, with tubeless tyres recently (2004) gaining favour for their pinch-flat resistance and ability to run at lower air pressures (improving traction). Mountainbiking is substantially more difficult than riding tar, as the inclines are substantially steeper, the footing treacherous, the downhills require absolute concentration, there’s no chance to wheelsuck and the ride requires more physical strength. Do not be fooled by a Mountainbike event’s relative shorter distance, it’s a lot harder. At the same time its much more interesting, fun, safer than onroad-cycling, and there’s more shade en route and panoramic views. A 30km road event is relatively easy, but a 30km mtb event will require your proper preparation and full attention… Mountain bikes can be classified into four primary categories, based on suspension:
There are several different applications of mountainbiking that all fall into one of the above 4 categories. Riding styles and equipment have evolved to suit different terrain, and deciding which bicycle is right for you will be easier if you know what type of terrain you intend to tackle. A common misconception is that a new rider needs more suspension because of the added control. While the added suspension may instil confidence in some technical sections, the frame geometry is not always suited to less experienced riders. Similarly, it might be hard to avoid the temptation of the ultra-light bike - the benefits are undeniable - but a novice rider can find racing bikes difficult to control when the trail gets rough. For the most part, mountain biking’s application can be split into five different categories:
Cross Country XC Racing Bikes: These bikes focus on efficient climbing rather than aggressive descent, and are designed to tackle a mountain from the bottom. They might sacrifice comfort and control as luxuries ill affordable when racing to the top. A typical XC Racer is (relatively) light with (relatively) little suspension travel (up to 110mm) in both the front and rear, and features ‘steeper’ frame geometry. Cross-country bikes handle abuse less well than other types of mountainbikes due to their lightweight construction. Suspension (typically short travel, semi-active designs) is typically provided by pneumatic shocks and forks - relying more on rider skill to negotiate rough terrain - and they are poor choices for jumps and stunts, but if your goal is fitness you’ve found the right bike! XC Trail Bikes: Trail (all-purpose) bikes are designed to climb with control and comfort, and to be able to descend at speed. With active suspension, knobbly tyres and low gearing the XC trail bike is perhaps slightly less efficient than the XC Racing bike going up, but it makes up for its shortcomings going downhill. As terrain gets steeper / rockier, the lighter XC Racing bike will ride roughly, but the XC Trail bike’s geometry will be ‘right at home’. If you like the idea of challenging yourself on a rocky climb, enjoy extended single track descents and want to battle it out going either up or down, a XC Trail bike may be for you. XC ‘All-Mountain’ Bikes: As outrides get longer and trails more remote, these bikes add value in their component’s reliability and downhill control. The bigger tyres, plush suspension and powerful brakes of the All-Mountain range are a sensible precaution against mishaps, at the same time being comfortable and a fun ride. With geometry suited to steep terrain and small drop-offs, All-Mountain bikes inspire confidence, however, on more mild terrain they could feel sluggish. If you’re an all-day adventurer or ride harsh trails, this is the ride for you.
Downhill bikes While cross-country riding inevitably has a downhill component, Downhill refers to basically bulleting down a mountain on a bike resembling an off-road motorcycle. It’s a test of nerve and about controlling the bike, picking the right line at speed, braking and cornering, literally ‘riding the edge’ plummeting down a mountain as fast as possible. Riders ride (individually) against the clock, starting at pre-determined intervals, and the rider with the fastest downtime wins. Downhill-specific bikes are built as strong as possible with extensively heavier frame tubing than other bikes - for reliability during racing – being universally equipped with massive front and rear suspension and large disc brakes. Downhill bikes are not meant to be pedalled uphill and need to be shuttled/walked to the top. Downhill courses are the most physically demanding and dangerous venues for mountain biking, and they include large jumps and drops being rough and steep from top to bottom. Downhill racers must possess a combination of strength, fitness, mental control and loads of body protection (a full face helmet with goggles and body armour). Downhill bikes typically weigh 20-30 kg, with up to 10-inches of rear suspension travel coupled with an 8-inch travel dual-crown fork. The suspension might be set to sag around 30% front and 50% rear (of full travel) to create the traction required around bumpy corners. The head angle is often as slack as 64 degrees, and due to the high-speed nature of downhill riding, most bikes’ transmission have only one 'big blade' / chainring, a large bash guard with chain guide. Mountain Cross or "4-cross racing" (4X) is a relatively new style of riding where four bikers race downhill on a prepared - BMX like - track, simply trying to get down first. These bikes are generally either full suspension with 3 to 4 inches of travel, or hardtails, and have, typically, quite strong frames. They run a chainguide in front, featuring slack head angles, short chainstays and lower bottom brackets useful for cornering and acceleration.
Freeride Bikes A "typical" Freeride bike is hard to define, but as the name suggests, Freeride is a 'do anything' discipline that encompasses everything from downhill racing, (with or without the clock) to jumping, riding 'North Shore' (elevated trails made of interconnecting bridges and logs), and generally riding trails and/or stunts that require more skill and "aggression" than XC as it includes some degree of stunts such as ramping. Freeride bikes are designed to ride extreme types of terrain such as steep chutes, large rocks and roots, big jumps and drop-offs, just about anything imaginable. Freeride bikes are generally sturdier and more amply suspended than their XC counterparts, but do retain some climbing ability (more often they are walked to the top, being inefficient due to the slack head tube angle making them difficult to manoeuvre while angled uphill or travelling at low speed). It is up to the rider to build the machine toward a preferred level of aggressiveness within 30-40 lbs of bike featuring up to 7-inches of suspension (front and rear). Freeride bikes are similar to All-Mountain bikes, but with less emphasis on weight, more on suspension. The components are built from stronger, heavier, materials. They can be ridden uphill. They are, very effective on technical downhill trails (frame angles are typically steep enough to enhance manoeuvrability.) Trials bikes Trials riding consist of hopping, skipping and jumping bikes over obstacles, requiring an excellent sense of balance. As with BMX riding, emphasis is placed on style, originality and technique. Trials mountain bikes are set up very specifically for the purpose of trials. Two varieties of trials bike exist, those with 26" wheels (referred to as 'stock') and those with 20" wheels (referred to as 'mod' - because historically they were modified BMX bikes). They typically have no suspension at all, though some still make use of some form of it. Competition rules require stock bikes to have multiple gears for competition (most riders never even use their shifters), but mod bikes are not required to have any gears, and many riders run a single, low-speed, high-torque gear. Most trials bikes have no seat as the rider spends all of his time out of the saddle. These bikes are significantly lighter than other mountain bikes, in order to allow manoeuvrability. Trials bikes look nothing like ‘mountain bikes. ‘
Other Bikes Dirt Jumping and Urban mountainbikes lie somewhere between a Trialsbike, a BMX and a Freeride bike. They are typically very strong with up to 4 inches of front suspension, but rarely rear suspension (3 to 4 inches if any), with as many as nine gears (or as few as one!) Tyres on these bikes are usually fast-rolling slick or semi-slicks. Dirt Jumpers usually sport a geometry based around 24-26" tyres, as well as a "bash ring" replacing the largest ring on the crankset. An interesting trend is that Dirt Jump and Urban bikes are more being equipped with rigid forks, as it enhances the rider's ability to transmit force to the ground, useful in performing stunts. The single-speed Mountainbike is considered a return to simplicity having minimalist drivetrain components & no shifters, but requiring a stronger rider. These bikes are a celebration of the simplicity of the original bicycle. Many experienced riders own single-speed bikes, finding their lack of complexity and weight benefit attractive qualities. Single-speed mountain bikes have one set gear ratio. The gear ratio chosen depends on the terrain, the strength and skill of the rider, and the size of the bike (a bike with 29" wheels often requires a different gearing than a bike with standard 26" wheels). Often single-speeds are fully rigid, steel-framed bikes, requiring a very fit individual to ride it in mild to moderate cross-country terrain! 29er Mountainbikes use 700c-sized wheels (as with most road bikes), but are wider and suited for tyres of two inches (50mm) width or more. The increased diameter of the wheel enables it to roll over obstacles better, whilst offering a greater tyre contact patch. It would seem that there is a fashionable swing towards these big wheelers.
What does it feel like? |
Despite mountainbiking’s range of strange looking machines and additional components, they remain subject to the basics of bicycling. The critical angles in bicycle geometry remain the angle of the head - and seat tube (as measured from the horizontal), which drastically effect rider position and performance. Steeper angles are more efficient for power, pedalling up hills and make for responsive handling. Slacker angles (leaning farther from the vertical) are preferred for high speed and downhill stability. New generation frames feature a lower stand-over height, are lighter & stronger with a raised bottom bracket sporting geometry that allows for much more spirited riding over obstacles like logs, rocks, bridges and ramps. 
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“A journey of 1000 miles must begin with a single crank-turn.”