Spring minute rates are how powerful the springs are. Stronger springs take additional energy to squeeze a specified amount. The greater aggressive and heavier riders will manage to benefit from stronger springs, but they additionally lessen the capacity to take up minor bumps. Springs, being Springs, take extra energy to squeeze when they go, thus we have spring “rate.” Any energy will start to squeeze a spring, it is how much the energy is needed to enhance per amount of movement that determines the rate.
Progressive springs have varying spring rates and commonly appear to have the spring coils tighter together over a portion of the spring length. The spring coils that are tighter together are meant to be softer than the remainder. As soon as a impact arrives, they give way initially, before coil springs connect against one another, after which the rest of the spring coils, which are stronger, begin to squeeze. Hence, the springs can be stiff enough for more aggressive riding whilst still having the ability to take up lesser bumps smoothly.
Sag is a gauge of how much the suspension drops down when the rider is sitting on the bike. When growing through holes, the wheels need to lengthen downwards to stay connected to the road. With no sag, even moving over minor bumps would let the wheels move off course. This kills grip. A little sag is useful. Sag also consumes your air suspension parts movement and this will lessen the capacity to take larger bumps with no bottoming. Too much sag is unacceptable. How much is correct? Lots of riders will give you you precise figures but the fact is that it has to be correct for you and, if you are a separate racer, this is not going to get condensed to a procedure. You simply have to attempt differing amounts until it feels appropriate.
Damping is the speed at which the suspension can move. It’s also controlled by valving or by the weight stickiness of the oil. Too much damping and the suspension will be too sluggish to take up the bumps. Not enough damping and the bike will give way onto and bounce off bumps like a pogo stick. Occasionally, you may be able to change compression and rebound dampening independently – this can be a benefit. Like everything else, the correct amount of damping hinges greatly on where, how, and what you ride.
Oil height is a gauge of how far down the oil level is in the fork tubes with the springs out and the fork fully compressed. Since the forks are sealed oil height is important. As they compress, the air pressure in them rises; rising air pressure in fact adds to the spring rate. Hence, as forks give way, the air in them acts similar to progressive springs. The higher the oil in the tube, the more pronounced this effect is. Oil level enables you to tweak how your suspension behaves in the bigger hits.
Air pressure by valves (tire-style) fitted to the forks at the top.. Frankly, the manufactures fitted these valves so you can remove air pressure out, not put it in. The forks will warm up as you ride and the air pressure will build up. Rising over a length, forks tend to “inflate” merely by just riding the bike over a length of time the forks tend to “pump up”. It is possible to temporarily tune your suspension to some unusual set of conditions; this is fine as long as you don’t add an excessive amount of air. The manufacturers do not recommend this as the forks seals could start leaking oil if there is too much air pressure in the forks. Also added air pressure will change how your bike handles, making it less predictable. Predictable is useful; it enables you to ride closer to the edge.
Bottoming is what happens as you hit a bump so hard that the suspension compresses to its limits. If you are bottoming frequently whilst riding about then you either have too soft of a spring rate, to not enough preload, excessive sag, insufficient fork oil, inadequate damping, or you don’t know how to ride perfectly.