16/03/2013 | 1 comments
Clive Forth is a rider with a lengthy and all-encompassing history in bikes. He’s raced everything, ridden everywhere. He knows everything there is to know about riding bikes and puts his knowledge to good use in his coaching sessions.
A TO Z OF MOUNTAIN BIKING SKILLS AND TECHNIQUES PART 2
Back to skills this week and moving onto the letter B. In the first skills piece we looked at anxiety and the mental state of riding technical trails. Once we have the brain fired up and tuned in we can take it to the techy stuff, we will of course need to control our speed and that involves this week’s major topic of brakes and braking.
brake 1 |brāk|
A device for slowing or stopping a moving vehicle, typically by applying pressure to the wheels:
• a thing that slows or hinders a process: managers have a duty to put the brakes on growth when it is unsustainable.
verb [ no obj. ]
make a moving vehicle slow down or stop by using a brake: drivers who brake abruptly | (as adj. braking) : an anti-lock braking system.
The vehicle in question here is not just the bike you’re riding but the combination of bike (chassis) and rider (engine and sophisticated electronics, abs, ecu, traction control etc.).
Obviously I should point out that you need to keep your brakes in good working order and condition, pay attention to pad wear, hose condition and make sure the brake feels firm, the pads contact disc perfectly. If you feel or see a distinctive change in your brakes and their performance get them serviced by a professional immediately.
With the boring warning stuff out the way we can now look at the set-up, lever position, bite point and so on. There are different schools of thought as to how your brake levers should be angled and of course there is an element of personal preference to be considered, the discipline or style of riding your doing may also influence how you set up your brake lever position. One thing is for sure, you need to be able to reach the lever blade with ease and not put any unnecessary strain on your fingers and wrist in the process.The angle of the (brake lever) dangle
For those of you riding smooth trails you will have less of a need to drive/push the bike through rough rocks roots and earth, this allows you to angle the brake lever further down. For riders hitting rough terrain you will need to get behind the bar, take impacts and drive the bike through the rough stuff, for this reason it’s wise to raise the brake lever so a slight angle appears in the wrist from the forearm to hand when viewed from the side. Remember to be stood up when you set this angle as you will be stood when descending and this is when we need our brakes the most.
If you sight a line down the Radius (forearm) then it should strike through the centre of the handle bar or lower. As the bike hits square edge features and compressions in the trail this will help brace your body as it moves forward. You can drive (push/punch) the bike out in front through trail features from this position.
I hasten to add that we are not static on the bike and the bar/grip will rotate in the hand to some degree, this means when viewed in certain still images we end up with our line drawn along the forearm passing above the bar, of course you can still move the bar forward, up, down, left, right in this position. It’s just less savoury to take a hit/deal with load when the hand, wrist and forearm are in this position (think about how you push a heavy shopping trolley or do push ups, then consider the angle you position your brake levers.)
Typically we appear to be above the bar when in the air and no resistance from the front occurs, back on terra firma get that dip in the wrist so the virtual line from the forearm strikes below the bar.Inboard/outboard
With the angle set you now need to set the inboard/outboard position.
You should use the index finger for maximum control positioned at the end of the lever with the end of the finger ‘hooked’ around the lever blade, this way the lever blade goes through the longest possible arc giving you maximum feel and control on the brake. You will be able to modulate the lever and feel how much bite (the contact of pad on disc) the brake has, there will be an element on movement in the lever even after initial contact of pad on disc has taken place, this progressive movement increases or decreases the power of the brake.
You can keep loading up (pulling) the lever until the power of the brake eventually overcomes the force acting on it (forwards motion of the vehicle, mass and velocity) then the wheel will lock. This progressive part of the lever movement is the one to make friends with, get used to this for optimum braking control.How much to brake
The amount of brake we use is another element that is in constant flux.
Predominantly we use more front brake than rear; think front for stopping, rear for control. Try and do your braking early and in a strait line. I appreciate this is not always possible when riding on steep gradients, here you may need to scrub some speed and that could mean braking in the turn. The problem with braking in the turn is the forces that act on the wheel from braking want to bring the bike upright and away from the trail surface, it’s a double negative. Try standing with your bike, lift the rear wheel and spin it up fast, now grab a handful of rear brake.
Over drops, wet roots and similar feature (typically when the wheel becomes airborne), we need to decrease and increase the pressure on the lever as the wheel passes over, it’s a constant juggling act between the two brakes and a skill that develops with time, patience and practice. Steep banks and square edge drops are a great place to test your braking ability, control and feel. Try riding down features as slowly as you can without skidding. When a wheel is locked it become less efficient at slowing, you need to keep engaging fresh rubber especially on wet and loose surfaces.
This is a huge topic and there are many ways to practice with various techniques, so I will look at braking again as we go through other skills.B is also for…
Backing it in sideways: sliding the bike sideways using controlled braking to scrub speed before the turn.
Berms: banked parabolic corners, these come in various shapes and sizes, some provide more support than others. We will look at berms when we cover C and corners.
Bike set up: the angles, distances and measurements on the bike, including: bar width, bar angle, bar rise, bar sweep, stem length, stem height, brake lever angle and reach, crank length, Q factor (width between the pedals), saddle angle, saddle fore/aft movement, saddle height, suspension settings, tyre choice, tyre pressures. (More on this next time.)
Bottom Bracket: the area of the bike the crank arms attach to, the tubular section between the seat tube and down tube. Also: The component part that fits into the frame and crank arms attach to, consisting of bearings (often seated in bearing cups) that are threaded into the bottom bracket tube, or pressed into the frame (BB30 system).
Boulders: large rocks, a step up from a rock garden is a boulder field.
Bouncing: the car park suspension test, a movement made by riders in a seemingly wasteful fashion as they roll down trail, pushing down on the bars/jumping on the pedals to compress suspension often before lifting the bike in the air. (More on this in B part 3 “Bunny Hop” and S for suspension.)
Bunny Hop: a skill where the rider raises the bike into the air, up onto and over trail features, typically without a take off ramp for assistance.
Clive Forth. MTBSkills, Transition Bikes.
Clive’s website: www.mtbskills.co.uk