If you have a dual suspension mountain bike, you probably know how important having a good rear shock is. A rear shock is a device that connects the frame and the rear wheel of your bike and helps absorb bumps and vibrations while riding. A rear shock consists of two main parts: a damper and a spring. The damper controls how fast the shock compresses and rebounds, while the spring determines how much force is needed to compress the shock.

Different Types on Offer

There are two types of springs for rear shocks: air springs and coil springs. Air springs use pressurised air to provide resistance, while coil springs use metal coils. Both types have advantages and disadvantages, depending on your riding style, preference and budget.

Air springs are lighter, more adjustable and more progressive than coil springs. This means they weigh less, can be easily tuned by changing the air pressure, and offer more resistance as they compress. Air springs suit most riders who want a versatile and efficient suspension system.

Coil springs are heavier, less adjustable and more linear than air springs. This means they weigh more, can only be tuned by changing the spring rate or preload, and offer consistent resistance throughout travel. Coil springs suit riders who want a plush and smooth suspension system that can handle big hits.

If you choose a coil spring rear shock, you must choose the right spring for your weight and riding style. Springs for coil shocks are rated using the spring rate and stroke length (e.g .450 X 2.25). The spring rate is measured in pounds per inch (lb/in) or newtons per millimetre (N/mm) and indicates how much force is needed to compress the spring by one inch or one millimetre. The stroke length is measured in inches or millimetres, indicating how far the spring can compress before bottoming out.

Choosing the right Spring Rate

To choose the right spring rate for your coil shock, you will need to know your rider weight (including gear), your sag percentage (how much your shock compresses when you sit on your bike) and your leverage ratio (how much your rear wheel moves compared to your shock). You can use online calculators or charts from different brands to find out what spring rate you need based on these factors.

To choose the right stroke length for your coil shock, you will need to know your shock size (the distance between the eyelets of your shock) and your maximum travel (how far your rear wheel can move up). You can use online calculators or charts from different brands to find out what stroke length you need based on these factors.

A good rear shock spring can greatly affect how your mountain bike performs on rough terrain. Choosing an air spring or a coil spring depends on what kind of ride you want: light and efficient or plush and smooth. Either way, ensure you get the right size to get the most out of your ride.