Motorcycle suspension may seem like some complex motorcycle system at first, but let me tell you that knowing your suspension system and what effect it has on your riding and how to adjust it to your riding style will help you keep your motorcycle in perfect condition.
With that said, we will teach you everything you need to know about your suspension system, like its components and how it works.
So how do motorcycle suspension systems work? The primary purpose of your motorcycle suspension system is to keep your motorcycle tires in contact with the surface. If there were no suspension or if your suspension was bad, your tires wouldn’t have traction when you ride over dips bumps or when encountering other road imperfections.
This article will cover everything related to suspension systems, so stay with us to learn more interesting and useful facts about your motorcycle suspension system. If you need any help regarding the motorcycle suspension systems, you will find it in this article.
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How Does Motorcycle Suspension System Work?
Motorcycle suspension is responsible for keeping traction of your tires when you ride over road or trail irregularities. Your suspension also plays a significant role when accelerating, braking, or cornering forces.
Motorcycle suspensions use a damper and spring combination for isolating both the rider and chassis from any ground and road imperfection that you may bump into during the ride. Depending on what type of motorcycle you have, there are on-road motorcycle suspension systems and off-road motorcycle suspension systems.
- On-road motorcycle suspension systems are responsible for minimizing the effects of cornering, bumps, potholes, and acceleration and deceleration forces that occur during the ride.
- Off-road motorcycle suspension systems minimize the effects of bumping into rocks, roots, ledges, and of course, our favorite jumps that we can’t imagine going for a dirt bike ride without.
If there were no suspension on your bike, every impact that would happen between your motorcycle tire and a road or ground imperfection would be very uncomfortable, or in the worst-case scenario, it would result in a crash.
Dual sport bikes and cruisers have various needs compared to sportbikes. It is characteristic for basic motorcycle suspension to lack adjustability, although it works pretty well in many different circumstances. Next to the basic motorcycle suspension, we have premium suspension, which is more adjustable, and a rider can tune it to its weight and riding preferences.
Suspension adjustability may include ride height with and without load, fine-tuning how fast will spring rebound or compress, and spring tension of preload, which conforms to different weights for various riding styles that can include luggage or a passenger.
Motorcycles mostly use a hydraulic damper setup and a coil spring on their suspension systems, although there are suspension systems that use air springs.
Spring
Springs let a motorcycle wheel rotate freely from the motorcycle chassis while dampers manage and control springs’ movement. It would be very dangerous if a motorcycle would have only springs while riding because a rider would bounce whenever hitting road imperfections like bumps or potholes.
Spring is a coiled wire that stretches or compresses when an external force impacts it. Every spring has a spring rate which is the force measurement needed to compress it a specific distance that is mostly written in pounds per inch. The spring rate is determined by the number of coils and material thickness. Springs capable of absorbing heavier duty have thicker coils that are spaced further apart.
- Linear Rate Springs: These types of springs give consistent resistance through spring travel. For example, if 20 pounds will compress the spring two inches, that means that 40 pounds will compress the spring four inches.
- Progressive Springs: These types of springs need more and more force to accomplish the same distance. These springs are characteristic for their structure which are mostly two or more springs combined in one, with narrowly and widely spaced coils. In the beginning, a smaller force compresses the first coils, and after that, a bigger pressure compresses all the remaining coils.
Damper (Shock Absorber)
A damper controls and slows the spring action using a hydraulic liquid that passes through a series of restrictions and passages. A piston has a precisely measured opening that travels in the shock body to a hydraulic fluid bath. The piston’s travel speed is determined by the size of the passage (opening) and the weight of the fluid.
When a rider hits a bump on the road, the dumpers will slow spring compression and rebound while the liquid slowly passes throughout the passages.
Spring movement creates kinetic energy that turns in the heat inside the damper, and the hydraulic liquid scatters the heat. Rear motorcycle shocks support an additional load and produce more heat than front forks.
Compression and Rebound Damping
Compression damping is the intentional slowing of spring compression that happens when a rider hits a bump, while rebound damping is the deliberate slowing of the spring expansion when a motorcycle gets back to its normal state.
Low and high-speed adjustments for rebound and compression damping can be found on some motorcycles. Off-road and sportbikes have more adjustability than entry-levels or cruisers.
High and low-speed damping indicates the suspension travel speed rather than the motorcycle’s speed. Damping at a higher speed has an effect on suspension behavior when a rider suddenly hits a pothole on the road or a rock on a trail. Damping at a lower speed has an effect on braking or cornering.
- Damper Rod: Suspensions compression and rebound are controlled by fluid that travels throughout a fixed orifice. Damper rods are not very expensive to manufacture, although they are restricted in effectiveness. High-speed damping is harsh, while low-speed damping is soft.
- Cartridge Forks: Suspension movement is controlled by fluid that travels throughout a set of stacked shims. When the fluid passes through the shims, it makes the shims bend and flex. Cartridge forks enable better damping starting from lower to higher speed and are more tunable. They are more expensive to manufacture and more complicated.
Sag
Your motorcycle springs are constantly under tension when you ride and even when your motorcycle is stationary. Your motorcycle weight causes compression all the time. If you ride alone, the compression is not so significant, but if you have another passenger with you and luggage, it will cause the suspension to compress much more.
Sag is the percentage of suspension movement used while your motorcycle is stationary. Your bike could bottom out when you bump into road bumps if the suspension sags too much when your bike is stationary. However, too little sag is also not good because it can lead to a stiff and harsh ride.
Preload
Preload is the quantity of tension on your motorcycle springs while your motorcycle is stationary. Adjusting preload of your suspension is an option on some motorcycles. If you increase your motorcycles preload, it will lead to decreasing sag. It is also the other way around; if you increase sag, preload will decrease.
Since most riders use the same bike when riding alone, riding with a friend, or having luggage on the bike, adjusting preload will enable a rider to adjust his bike for multiple different ride styles.
You can increase ground clearance by adjusting preload for off-road rides or even decrease your seat height if you are a short rider, but this is not recommended to do. Some riders use preload as a band-aid to deal with inappropriate stiffness of their springs related to their weight and heights. Although this is not an ideal thing to do, it is a usual practice because replacing your springs is both expensive and takes hard work.
Motorcycle Front Suspension
A motorcycle uses suspension forks on the front end. Some motorcycle suspension systems use both dampers and springs working with each fork leg. Other bikes have one fork leg that contains the damper while another leg contains the spring. These are called separate function forks.
The front-wheel axle is placed on the suspension fork’s lower end, while the triple tree makes the top end secured.
Motorcycle Rear Suspension
On the back end, you can notice a heavy-duty coil wound placed around a damper, together with external adjustments for damping and preload. If we compare the rear motorcycle suspension to the front one, we see these heavier-duty springs because the rear suspension carries a lot more weight than the front suspension.
Here is a nice video about motorcycle suspension working principles which I find very interesting and helpful:
Final Thoughts
Motorcycle suspension significantly affects your riding because the suspension system makes your riding feel much more comfortable, especially when you bump into road bumps and other imperfections (although even the best possible suspension can’t eliminate that awful feeling of hitting bumps).
In this article, we covered all the important and valuable information that we think you should know and will be helpful to you.