 Suspensions are one of the most important parts of a dirt bike, but the majority of people in the off-road community don't really know much about this topic. People look at the work done in suspension workshops as some kind of voodoo magic, but it isn't. That's why I decided to share with you everything I've been learning about suspensions, not only from my own research, but with the partnership we made with Technical Touch and KYB. A well-tuned suspension can be far more important than the horsepower of the engine. If you can't put the power to the ground in an efficient way, it becomes useless. A factory team spends far more time finding the perfect suspension setup than looking for extra horses to add to the engines. And why is that? Well, the riders only know how to use the power if the suspensions allow them to do so. Let's break this down. Suspensions have two goals. The first one is to absorb and compensate the irregularities of the terrain, keeping the wheels in contact with the ground as much as possible, allowing maximum traction. If your wheels are getting airborne every time they hit a bump, you won't be able to accelerate, making all the power useless. Also, you won't be able to brake, so never mind trying to go fast. The second one is to allow you to ride smoothly on a rough terrain, keeping the bike under control and avoiding a sore butt at the end of the day. But what exactly are the suspensions? How do they absorb the bumps? Suspensions are made of two distinct components, a spring and a damper. Both serve different purposes, but one does not work without the other. The job of the spring is to handle the amplitude of the terrain, meaning that the spring only cares about where the wheel is on the stroke, which makes it position sensitive. The spring does not care how fast it compresses or extends. It will exert the resisting force against its compression according to the spring rate. Usually, this value is given in newtons per millimeter, meaning that the spring provides a resisting force that increases at a linear rate. The spring converts the kinetic energy transmitted by the wheel hitting a bump to an opposing force, releasing that energy by pushing the wheel back down, so the wheel will keep in contact with the ground. Then there's the damper. The damper isn't as simple to explain as the spring, since its ability to dampen depends on its complexity and the fluid. We'll focus on the fluid for now. Oil is the most commonly used fluid by far. The damper couldn't care less about how high on the stroke it goes. It only worries about the speed of compression, meaning it's speed sensitive. As long as things go slow, the damper doesn't have to do much. The damping effect occurs when you try to force the oil to pass through or offices faster than the oil can get through them, just like in this range. Imagine the oil being a crowd of people trying to get in a store on a Black Friday. It doesn't matter how hard you push the crowd from the back. If people can't get in as fast as you are pushing, you'll have a resisting force from the crowd slowing you down. That's damping. Something that confuses a lot of people is the concept of damping. More damping means more restriction to oil flow, which translates into a greater resisting force, making the forks compressed slower. Less damping means less restriction to oil flow, which translates into a smaller resisting force, making the forks compressed faster. Wrapping up. More damping means compressing slower, and less damping means compressing faster. The oil's resistance to that flow can vary according to numerous things, but the easiest way to change it without changing anything on a suspension's hardware is through the oil's kinematic viscosity. A more viscous oil will provide more damping, and a less viscous oil will provide less damping. Anyway, when the oil goes through the orifices and the canals on the damper, it converts the kinetic energy of the compression into heat, thanks to viscous friction. That's why when you ride on a really rocky trail or on a motocross track with big jumps, the shock tends to heat up. That's supposed to happen. Using a spring or a damper alone doesn't do much, but when you combine them both, something wonderful happens. When the wheel hits a bump, the wheel compresses the suspension at a controllable speed, thanks to the damper. While the spring doesn't let the wheel go too high on the stroke, thanks to its increasing resistive force throughout the compression. When the bump is cleared, the spring releases the stored energy on the coil and pushes the wheel back down again to its neutral position. This happens at a controllable speed since the damper is there to slow down the wheel on the rebound. As you can see, the damper has a bit more impact on the way the suspension behaves, and it's clearly where the tuneability brings more results. And in most cases, tuning the compression damping brings more results than tuning the rebound damping. On compression, you have several forces involved that affect traction. It can vary according to the bike and the rider's weight transfer, the speed of the bike, and the inputs of the terrain. While on rebound, it only has to maintain contact with the ground or reduce airtime as much as possible. These are the fundamentals on how suspensions work, and these are really important concepts that you should fully grasp before getting to more advanced topics. You need to learn how to walk before you can run, right? In the next episodes, I'll explain you the different setups, technologies and components that make suspensions work in a far more sophisticated and tunable way. So don't forget to hit that subscribe button and on the bell icon to get the notifications. Thank you for watching and stay tuned for the next episodes.