The letters sound like cries for help. And some of them are. "Help! My new fully, which was praised so highly in the tests, just rumbles over the roots." Or: "I'm only using half the travel of my fork, even though I've set the air pressure exactly to the manufacturer's specifications. Why is that?" These and similar questions reach the editorial team incessantly. - "Have you tried turning up the rebound a little more?" is often one of the first expert suggestions. The answer usually already hints at the reason for the misery: "Rebound? What's that ...?"
The suspension technology of mountain bikes has developed massively in recent years. Never before have even long suspension travels been so versatile. Riding uphill with 160 millimetres of travel and yet downhill with uncompromising performance? Unthinkable years ago. Today, sophisticated valve and shim designs in suspension forks and shocks, new low-friction seals and bearings as well as countless other details ensure maximum sensitivity, fully usable suspension travel and possibilities like never before.
However, even the best shock and the most expensive suspension fork can only fulfil their potential if they are correctly adjusted to the rider. Only then will the suspension provide optimum traction, comfort and riding safety. No matter how much effort the manufacturer has put into the design and set-up of the bike, if the rider does not adjust the fork and shock correctly, the hoped-for aha experience will fizzle out. The high-tech bike becomes a stubborn donkey. It is estimated that more than half of bikers ride with the wrong setup and often don't even realise it. The scene forums on the internet are full of comments in which bikes are accused of having poor suspension characteristics. In reality, it is mostly a matter of deficits in the setup.
Many bikers are overwhelmed by the numerous, increasingly complex adjustment options of modern suspension elements. They are therefore happy to leave the subject to the specialist dealer. Admittedly, there are high-tech parts that are only suitable for technical experts and absolute specialists due to their options. But the vast majority of forks and dampers are designed in such a way that the correct setting only takes minutes. It is not difficult at all to learn and understand the small one-time-one of suspension. Here we show how the individual adjustment options affect the riding behaviour. In simple steps, everyone can find their own ideal set-up. So throw your fears of contact overboard.
You don't need much for perfect tuning. A standard shock pump (see illustration below) and a ruler or measuring stick are all you need. And then you can indulge in unadulterated trail enjoyment instead of typing desperate cries for help into the computer keyboard.
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TROUBLE SHOOTING
The chassis doesn't always work the way you want it to. Here are the most common problems and their solutions:
■ The symptom: The fork or the shock absorber often puncture.
■ The cause: Spring stiffness/air pressure or compression damping are too low.
■ The solution: The first step is to use the sag to check whether the spring rate is set correctly. If this is correct, you can possibly increase the compression damping or optimise the progression by using volume spacers. Increasing the air pressure also helps, but worsens the response behaviour and often reduces the usable suspension travel.
■ The symptom: The chassis is not very comfortable, offers little traction and the suspension travel is not fully utilised.
■ The cause: The suspension or damping settings are too tight, or there is too much friction in the system (e.g. due to dirt in the bearings).
■ The solution: The causes must be clarified individually. The suspension/damping settings can be checked after the above steps. The only way to detect dirt in the fork or bearings is to dismantle the bike - or have it serviced.
■ The symptom: The suspension feels spongy, especially in bends or on rougher trails.
■ The cause: The rebound or compression damping or the spring rate are set too soft. Also possible: Bearing play has developed in the system.
■ The solution: Bearing play in the wheels and the rear triangle can be easily recognised by pressing on the side of the installed wheel. The correct suspension setting can be checked using the sag. Readjust the damping setting as shown above.
■ The symptom: The suspension responds well to single impacts, but hardens on fast impacts.
■ The cause: The rebound damping is set too tight, which is why the shock and fork cannot extend quickly enough.
■ The solution: Gradually reduce the rebound damping until the suspension still generates comfort on root trails and gravel tracks without starting to bob uncomfortably or become unsettled.
■ The symptom: Even with great care, the chassis cannot be optimally adjusted to the rider's weight.
■ The cause: For particularly light riders (under 60 kg) and particularly heavy riders (over 125 kg), the factory set-up of the suspension elements reaches its limits.
■ The solution: The only thing that helps here is to consult the manufacturer of the bike or the suspension elements and order an optimised damping tune. Sometimes it is also helpful to have a custom tuning carried out.
■ The symptom: The suspension tends to bob annoyingly when pedalling out of the saddle or during normal uphill riding.
■ The cause: The low-speed tension or compression setting is too soft.
■ The solution Your bike may have switchable platform damping. Switch this on. Better? If this is not enough, you can increase the platform strength or the low-speed compression damping separately on some forks and shocks. A harder rebound stage also has a calming effect, but has the disadvantage that the suspension hardens too quickly.
■ The symptom: The fork and damper do not always work evenly.
■ The cause: Contamination from foreign particles or internal wear/corrosion prevent the spring elements from working properly.
■ The solution: This clearly calls for immediate servicing, otherwise there is a risk of serious damage and even higher repair costs. Exception: After very long downhills, air and damping oil can mix in so-called "open systems". In this case, a short break is usually sufficient.
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LEXICON
The world of bike suspension is teeming with technical terms. To set up your bike correctly, it is enough to know a few basic terms:
Suspension (air or steel spring) Their task is to absorb the kinetic energy that acts on the bike and rider when travelling over obstacles or after jumps and store it as potential energy.
■ Attenuation This is what brings calm to the chassis and ensures control. The energy of the suspension process is converted into heat. This is usually done by forcing oil through a series of valves and around metal plates (shims). This calms the suspension speed of the fork and damper.
■ Positive threadr It is what is commonly understood by "suspension". Its force acts against the direction of compression and pushes the fork or damper apart. Today it is usually an easily adjustable air spring.
■ Negative spring It aims to compress the spring element and is responsible, among other things, for sensitivity in the initial spring travel. It is intended to minimise the influence of static friction (breakaway torque) and improve the response behaviour. Depending on the system, it is designed as a steel spring or as an air spring, which is filled simultaneously with the positive spring via a valve.
■ Say (negative suspension travel) The part of the suspension travel by which the fork and shock are compressed by the rider's weight alone. One of the most important parameters in suspension adjustment, as all rear suspension systems are designed around defined sag values.
■ Rebound damping (Rebound) It regulates the rebound speed and thus influences many aspects of the suspension performance. Controlled via the red adjustment knob on almost all suspension elements.
Compression damping (compression). It regulates the compression speed of the spring elements
and thus supports the positive spring. Controlled via a blue adjustment knob on almost all suspension elements.
High/low-speed damping Modern suspension elements have multi-stage damping circuits in order to remain bob-neutral on slow impacts (bumps) and still be able to react effectively to fast, large impacts. The adjustment options of most systems only affect the low-speed rebound and compression stages - with a fixed high-speed setting. However, some also allow adjustment of the high-speed range.
Platform damping/lockout Functions that can usually be selected via levers, which greatly calm the suspension activity (platform) or completely lock it out (lockout) through firmer (compression) damping - at the expense of comfort and traction.
at the expense of comfort and traction.
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