Suspension at the macro level is composed of just a few simple elements. The first being springs. Springs were first used in buggies and cars to smooth out the ride. The second element is the damper; it was designed later to control the oscillations of the spring. The spring's primary job is to support the weight of the bike and the rider.

Many times I have been told that a damper is worn (Shock or Fork) out and the rider knows it because the bike is sagging more under its weight. This is a false notion. The only thing that supports the weight of the bike and rider is the spring. It is a very simple fact the spring is the only significant supporter of total vehicle mass that is currently in use in offroad bikes. The key word is significant. While it is true that a bike with worn, broken, or under-damped valving will feel off and bouncy, it will settle no more or less under weight, regardless of damper condition.

What do I mean by significant? I would be fairly sure that most of the readers of this article have at one point or another taken a shock with no spring on it and compressed it. Think back and remember what its characteristics were like. Depending on the model, I'm sure that you noticed that it compressed with relative ease, when compressed slowly. The faster you tried to compress the shock, the harder it became, right? We'll talk more about why that is, in future articles, but specifically the shock will compress completely with very little force being applied to it. (10-20 lbs. of force should suffice to compress it completely.) Ok, so what accounts for that small force? The shock is gas charged; the compression rod of the shock displaces oil, which compresses the gas charged bladder in the shock. Following very simple hydraulic principles (over simplified for the example), the rod, even though it has say 180lbs of nitrogen behind it, has an area of 1/10th the bladder, so it could have about 18 lbs. of extension force. If the rods diameter increases the force extending it increases as the ratio of areas becomes closer to one. Eventually at some point, the rod and therefor the damper becomes a significant supporter of mass like a spring, but on current bikes this is not the case. What negligible mass the damper does support, is reduced even more as the force is reduced by the lever ratio of the swingarm.

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