A General Guide to Mountain Bike Suspension Terms and Set-up
Today’s mountain bikes are potpourris of technology. Nowhere is this more evident than in the suspension department. While many riders find themselves lusting after the most feature-rich forks and shocks available, not nearly as many understand exactly how much control they have over the way the suspension performs or how it’s performance can affect handling.
Let’s start with the basic suspension controls, what they do, and why you should adjust them.
Preload: This adjustment controls the tension of the fork or shock’s spring(s). Most forms of suspension rely upon the resistence of a spring both in action and at rest. Controlling the spring preload stiffens or softens the suspension directly and immediately. Gains are made if the suspension blows through it’s travel on small impacts (requiring increased preload) or rides too high in it’s travel, decreasing small bump sensitivity (requiring a decrease in preload). Generally speaking the preload adjuster should be the first on your tuning list.
Compression Damping: As the name suggests, the compression setting controls the internal shaft’s ability to compress as the damping process (the transfer of oil through resistant openings) takes place. The main benefit to fine tuning the compression adjustment lies within the boundaries of being stiff enough to absorb big hits and square-edge bumps (without bottoming out) while, at the same time dipping into it’s travel enough to allow the bike to corner low and level uneven terrain.
Rebound: The purpose of rebound settings is much simpler then the process involved to make it happen. Rebound basically controls the rate at which the suspension unloads after having been compressed. That spring we spoke of above would be quick to pop back up into it’s uncompressed state (bringing the shock body with it) if it weren’t for the rebound process. Here the compression damping again comes into play, only this time the transfer of fluid through a resistant opening occurs in reverse. The end result? A slowing of the spring’s ability to pop the suspension upward. The benefit of dialing in the rebound setting relates directly to the suspension’s ability to quickly recover from staggered obstacles or g-outs while at the same time eliminating any feeling of the bike attempting to kick back on hard landings.
Lockout: Suspension lockout is the answer to a quickly fading question: Does suspension rob pedaling efficiency and terrain feedback? The reality is that with each generation of refinement, suspension builders are making steady progress in the area of suspension that resists pedal bob while remaining active. Even still there are riders who wish to emulate the feel of a hard tail (or rigid, for climbs perhaps) who will seek the lockout setting. Basically the lockout control bypasses the damping network of the suspension, creating a near rigid feel without giving up the luxury of suspension once the climb is complete.
While we can’t give specific settings for each and every fork and shock on the market (this server is only so big), we can offer some universal tips to making the most out of your suspension settings.
1) Consult your owner’s manual.
The engineers behind each suspension design have gone to great lengths in terms of testing and development. Their findings are all listed within the manual meaning the proper adjustments required for your body weight, riding style, and terrain are all contained within.
2) Set your sag.
The very first step of adjusting your suspension should be to follow the manual’s technique for setting your sag (or amount of travel used simply by the rider’s weight). All of the later adjustments cannot compensate for the bike’s handling traits if the sag isn’t measured and set accordingly.
3) Lastly be weary of suspension swaps.
One of the most common areas of erroneous thinking stems from riders attempting to get more out of their rigs by simply slapping on longer travel components. The reality is that frame designers carefully select the components that work best with their engineering goals. Research suspension swaps very carefully before purchasing as a bike’s delicate geometry can be easily disturbed