Your mountain bike suspension goes up and down, sure. And you know there are a range of adjustments to make it feel and act differently. But have you ever wondered exactly what all those parts are. Here we’ve developed an anatomy guide to your rear shock that enables your frame to pivot and absorb impacts. Depending on the manufacturer, some of the parts might go by a different name.
The air can is the bulk tube on the shock that the lower components slide into. This chamber also houses the positive and negative air pressures and creates the primary spring effect as the shock moves through its travel. The air can threads into the top or head of the shock and normally has a manufacturer label on it.
Like a suspension fork, a rear shock also has a stanchion. On the shock, the stanchion is the section on which the air can slides. This piece is made of smooth aluminum to guarantee steady gliding action and optimal responsiveness.
Also called eyelets, the mount points are thru-holes that allow the shock to be bolted to a bicycle frame. Within the eyelets are DU bushings, a wearable component that reduces tolerances between the eyelet and hardware for a snug fit. All mounting hardware is manufacturer-specific.
The damper body or stanchion has two functions. The outer slick surface acts as one part of a seal system to maintain pressure in the air can. The other function is to house fluid, metal shims, a piston, and an internal floating piston (IFP). These components together regulate compression and rebound forces by using adjustments to open and close ports that allow the fluid to move through the system.
Compression
The blue knob - compression adjustments restrict how freely the fluid moves through the damper via ports and shims. The more restrictions, the more firm your shock will feel. Depending on the manufacturer, compressions adjustments will have a fully open or soft setting and a firm or even locked out setting plus additional settings in the middle for fine tuning to personal preference.
Air Pressure or Coil
Air pressure or metal coils work in tandem with the compression settings and are the main dictator of how the shock will ride in terms of sage, softness, and firmness.
Rebound
Rebound works in the same way of compression but with the opposite effect. After a shock is compressed it will rebound toward its beginning position. The rebound adjustment uses ports and shims to restrict the flow of oil in the damper to slow or speed up the rate of rebound.