Mountain Bike Shocks:
How to Choose and Adjust Them
to Fit your Riding


Mountain bike shocks...can you imagine riding without them? The first mountain bike suspension forks became available in the early 1990s. Before that, mountain bikes had a rigid frame with no bicycle shocks, so the tires and the rider's body were what absorbed most of the impact.





Not only do mountain bike shocks absorb the impact of rocks, roots, drop-offs, logs, and other obstacles, but they also allow the bicycle wheels to have more contact with the ground, which means more control.


Skip all this talking and find deals on reputable brands of shocks here!



Today, most mountain bikes have some type of suspension system in them, either in the front only or in the front and rear. Bicycles with shocks in the front only are called hardtail mountain bikes. These bicyles have shocks built into the mountain bike fork. The mountain bike shocks in the fork of the bicycle allow the front wheel to move up and down to absorb impacts.



In addition to having front mountain bike shocks, many bicycles also have suspension built into the frame. These bicycles are called full suspension mountain bikes.

The rear suspension system is made up of a rear shock and pivots built into the frame of the bicycle.

The introduction of mountain bike shocks and their improving technology has made it possible to ride increasingly larger and more challenging obstacles.


Whether you are looking at buying a new mountain bike or upgrading your existing bike with mountain bike shocks, it is important to know what type of riding you will be doing. Do you plan to ride smooth trails with little bumps, ride as fast as you can down a mountainside doing large drop-offs and jumps, or something in between?

If you would like tips on choosing a mountain bike based on the type of riding you want to do, please visit our page on Types of Mountain Bikes and then click your back button to return to this page.


Types of Shocks
Parts of Mountain Bike Fork
Parts of Rear Shock
Travel
Preload and Sag
Damping
Motion Control Adjustment
Replacing Your Shocks


Types of Mountain Bike Shocks

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The 2 major types of mountain bike shocks are coil and air sprung. Coil shocks have a metal coil and air sprung have a chamber. Some shocks are also made of a combination of coil and air sprung.


Air sprung:

Air sprung mountain bike shocks are lighter than coil shocks and are seen in most cross country mountain bikes. Air sprung shocks often have many features that are able to be easily fine tuned by turning a knob or dial to fit your riding preferences, weight, and terrain.


Metal coil:

Metal coil mountain bike shocks can take bigger impacts and are heavier. They are also easier to service than air sprung shocks if they break. They are more reliable because if the seals fail, it will still have some bounce; whereas, with an air shock it will bottom out and not work at all. Coil shocks are typically seen in downhill and freeride mountain bikes.

Parts of Mountain Bike Fork

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A. Crown

B. Air cap to adjust preload

C. Stanchion tube

D. Lowers

E. Compression damping adjustment knob




Parts of Rear Shock

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A & G. Mounting bolts

B. Motion control adjustment

C. Lockout switch

D. Rebound adjustment dial

E. Air can

F. Travel indicator




Travel

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The coil or chamber is what enables the shock to move when pressure is applied to it. The amount a mountain bike fork can be depressed when pressure is applied to it is called its travel.

For a rear mountain bike shock, the travel is affected by the distance that the shock moves, which is called its stroke, and also how much the frame moves because of its linkage system. This is measured by how much the wheel moves when the shock is compressed.

More travel in the mountain bike shocks is better for going downhill, but less is better for climbing. Typically, cross country mountain bikes have around 3 to 4.5 inches of travel. Downhill and freeride mountain bikes usually have around 6 to 10 inches. All mountain mountain bikes fall somewhere in the middle.

Some higher end mountain bike forks have an external adjustment which is often a dial at the top of the fork to change the amount of travel as you are riding. This way, it is possible to decrease the travel for better climbing performance and increase it for downhill sections.


Preload and Sag:

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When setting up mountain bike suspension, it is important that the shocks are set to be compatible with your body weight. This adjustment is called spring preload. Too much preload will give you a stiff ride and too little will cause your shocks to bottom out too easily.


Measuring sag:

In order to adjust preload, the first thing to do is measure sag, which is how much the bicycle shock compresses when you sit on the bike when it is not moving.

On a cross country mountain bike, the sag should be about 25% of the shock's total travel. For example, if your total shock travel is 100 mm, you would want around 25 mm of sag. On a downhill or freeride mountain bike, the sag should be around 40%.

To measure sag in your mountain bike fork, you can attach a zip tie to the bottom of the stanchion tube. Using a wall to support you, get on your bike and assume your riding stance. Measure the distance of the zip tie to the bottom of the stanchion tube.

On rear air shocks, there is often a rubber ring around the shaft so you can use the same technique as the one used to measure sag in the fork.



On rear coil shocks, you need a buddy to help you measure the sag. First, measure the distance between the centers of the mounting bolts. Then, get on your bike and assume your riding position. Have your buddy measure the distance between the centers of the mounting bolts while you are in the riding position. Subtract this distance from the distance before you got on the bike.

The sag of the mountain bike fork and the rear shock should be similar so your bike is balanced from front to rear.

If you have too much sag, the preload is set too low and you need to increase preload. If you don't have enough sag, the preload is set too high and you need to decrease preload.


Adjusting preload:

On air shocks, the preload is adjusted by adding or removing air from the shock. This is done with a shock pump that attaches to a Schrader valve in your shock. To increase preload, add air. To decrease preload, remove air.

On coil shocks, adjusting the preload is often done by adjusting a screw knob on the top of the fork and a spring collar on the rear shock. Also, you can put in a lighter or heavier spring that is more compatible with your weight.


Damping

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Damping controls the speed the shock moves. Most dampers are filled with oil and some have air. The oil or air is pushed from one chamber to another through small holes. Low end bikes sometimes have an elastometer, which is a spongy or rubbery material, to control damping.

Most high end air mountain bike shocks have external adjusters for adjusting damping. Some coil shocks have them, but others do not.


Compression Damping:

Compression damping controls how quickly the shock compresses when it hits an obstacle. Higher compression damping makes the shock move slower and lower makes it move faster.

If the compression damping is set too high, the shocks will provide a harsh ride and not reach their full travel. If the compression damping is set too low, the shocks will bottom out too easily and you will have a lot of shock movement when pedaling.

To adjust the compression damping on air shocks, there is often a labeled dial or knob on the top of the fork and also a labeled dial somewhere on the rear shock if it has this feature.

Some mountain bike forks and rear shocks have a lockout feature so the shock can turned off when it is not needed. This feature is often controlled by the compression damper adjuster. Some high end shocks have a thumb lever.


Rebound Damping:

Rebound damping controls how quickly the shock bounces back after pressure is applied to it. Higher rebound damping makes the shock return slower and lower makes it return faster.

If the rebound damping is set too high, the shock will not able to rebound before hitting the next obstacle and bottom out. If the rebound damping is set too low, the wheel will bounce back too quickly, which can cause the wheel to come off the ground or lose traction.

The goal is to have the rebound setting low enough so you are getting enough travel without the the bike feeling uncontrolled.

The rebound damping adjustment is usually a dial located on the bottom of the fork. If the rear shock has this adjustment, it will typically have a labeled dial as well.


Motion Control Adjustment

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Bob is the amount of movement in the front or rear shock that occurs when pedaling. the goal is to have the least amount of bob possible while still being able to access the full travel of the shocks when needed.

Some mountain bike shocks have an adjustment to address bob, which is a form of low speed compression damping. This is sometimes called a motion control adjustment or pedaling platform adjustment.

With the motion control adjustment set, the shock does not move as easily unless it hits a bump. Then after hitting the bump, it goes back to the efficient pedaling mode.

Sometimes this setting is a dial on your shock or it may be an on-off switch. If it is a dial, you can adjust it so the shocks will move when impacted by your chosen level of force.

For more information on customizing the fit of your mountain bike, including tips on handlebar and seat adjustment and frame size, please visit our page on Mountain Bike Fit


Replacing Your Shocks

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Because of how the linkage system of your mountain bike frame interacts with the rear shock, it is important to measure your old shock if you are planning to replace it. To do this, you just measure from center to center of the mounting bolts.

Also, make sure the travel of your new shock is the same as your old one so you can get the maximum travel of your frame's capacity. If you have too much travel, it can damage the frame.

If you are replacing the mountain bike fork in your existing bike, it is also important to check the specifications of your frame to make sure it can accommodate the mountain bike fork you are considering.


Also, make sure the fork is compatible with your wheel and brake system.


Reputable Mountain Bike Shocks

The following are reputable brands of mountain bike shocks that are currently at discounted prices:


Marzocchi Forks - Up to 57% off forks. Most eligible for free shipping.

RockShox Forks - Up to 47% off forks. Free shipping.

Fox Forks -up to 41% off. Free shipping.



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