ghostnote
Well-Known Member
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- #1
Copying liberally from this article: http://www.hotrod.com/articles/shock-absorber-shock-dyno/
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There are three major categories of shock absorbers, which are based on the way they react to force. (Note: This is not a discussion of shock absorber design, meaning twin-tube versus mono-tube.) The first shock absorbers were progressive, meaning that as shaft speed increases so does the damping rate, or the energy required to move the shaft at that speed. A progressive shock is the simplest design, and also the least useful in practical terms. It’s simply a perforated disk moving through a resevoir of oil. At slow speeds the oil passes through the holes in the disk easily. At higher speeds more energy is required to move the oil through the holes in the perforated disk.
Eventually this type of shock reaches hydraulic lock—no matter how much force is applied to the shaft of the shock, travel speed cannot be increased. A progressive shock is old technology, and it’s performance is unacceptable to the modern racer. Low, continuous forces like body roll through a turn are too poorly damped, and on the other end of the spectrum the shock is unable to absorb sharp, high energy forces: holes, ruts and otherwise rough tracks.
Linear shocks were the next big advance in shock technology. As shaft velocity increases, damping forces increase at a linear rate. On a shock dyno graph (Diagram B) both compression and rebound damping appear as approximately straight lines diverging from each other as shaft velocity (or force exerted on the shock) increases. This style of shock has been a boon for racers because it allows increased control at lower shaft speeds, which is vital for controlling a race car through the corners.
The third type of shock is a fairly recent development. Digressive shocks are essentially the oppostive of progressives. As shaft speed increases, damping forces increase at a decreasing rate. Diagram C is a shock dyno graph of a typical digressive shock dyno curve. Digressive shocks provide low-speed damping control without being unreasonably harsh on rough racetracks. Both modern linear and digressive shocks allow separate damping and rebound rates. So far manufacturers have not been able to combine, say, digressive rebound with linear compression in one shock yet.
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I like the idea behind digressive shocks, especially for a daily driver. Does anyone know of digressive options for the S550? Better yet, if anyone has them installed, how do they ride?
_____________________________
There are three major categories of shock absorbers, which are based on the way they react to force. (Note: This is not a discussion of shock absorber design, meaning twin-tube versus mono-tube.) The first shock absorbers were progressive, meaning that as shaft speed increases so does the damping rate, or the energy required to move the shaft at that speed. A progressive shock is the simplest design, and also the least useful in practical terms. It’s simply a perforated disk moving through a resevoir of oil. At slow speeds the oil passes through the holes in the disk easily. At higher speeds more energy is required to move the oil through the holes in the perforated disk.
Eventually this type of shock reaches hydraulic lock—no matter how much force is applied to the shaft of the shock, travel speed cannot be increased. A progressive shock is old technology, and it’s performance is unacceptable to the modern racer. Low, continuous forces like body roll through a turn are too poorly damped, and on the other end of the spectrum the shock is unable to absorb sharp, high energy forces: holes, ruts and otherwise rough tracks.
Linear shocks were the next big advance in shock technology. As shaft velocity increases, damping forces increase at a linear rate. On a shock dyno graph (Diagram B) both compression and rebound damping appear as approximately straight lines diverging from each other as shaft velocity (or force exerted on the shock) increases. This style of shock has been a boon for racers because it allows increased control at lower shaft speeds, which is vital for controlling a race car through the corners.
The third type of shock is a fairly recent development. Digressive shocks are essentially the oppostive of progressives. As shaft speed increases, damping forces increase at a decreasing rate. Diagram C is a shock dyno graph of a typical digressive shock dyno curve. Digressive shocks provide low-speed damping control without being unreasonably harsh on rough racetracks. Both modern linear and digressive shocks allow separate damping and rebound rates. So far manufacturers have not been able to combine, say, digressive rebound with linear compression in one shock yet.
___________________________________________
I like the idea behind digressive shocks, especially for a daily driver. Does anyone know of digressive options for the S550? Better yet, if anyone has them installed, how do they ride?
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