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Fluid viscosity effects are accurately computed by ReStackor pro

In test rides of your bike if you find your suspension works better in some situations with thinner or thicker oil you can use the viscosity relationships of ReStackor pro to quantify the suspension damping forces produced by that oil and retune the stack to reproduce those forces at specific wheel speeds using another oil viscosity. The effects of fluid viscosity on the flow rate of fluids are well known and the fluid dynamics community has developed relationships capable of accurately modeling these effects. ReStackor pro uses these relationships to accurately compute viscosity effects on real world suspension components. This is demonstrated below through comparison with the dyno test data of www.supercross-online.de.

ReStackor pro calculations accurately model pressure drops through orifice flow circuits and accurately model effects of fluid viscosities on that pressure drop. ReStackor pro calculations are also capable of accurately computing the effect of fluid viscosity on flow rates through the valve face shim stack as shown above through comparison with the www.supercross-online data.

These fundamental fluid dynamic capabilities of ReStackor pro allow you to take your real world experience and experiments with clicker settings and fluid viscosities and use that information to retune the shim stack to produce specific suspension behaviors at specific suspension speeds. This significantly streamlines the tuning process and eliminates months of shim reshuffling that used to be required to do something as simple as add a few clicks to the mid speed suspension stiffness.

ReStackor pro uses real world commercial suspension fluids

The SAE wt standard was developed for characterization of commercial lubricating oils and allows a range of viscosity variation for “in spec” fluids. While adequate for lubricating oils these “in spec” ranges are too broad for characterization of suspension fluids. Data complied by Peter Verdone shows the viscosity of commercial 10 wt fork oil to vary over the range of 5 wt to 15 wt viscosities. Special care is need when comparing numerically computed damping rates to insure that the viscosities of the actual fluids tested are known and not simply read of a can.

ReStackor pro uses the Peter Verdone viscosity data for Silkolene. Effects of temperature on viscosity are scaled using the Andrade[1] correlation. This allows ReStackor to match reported viscosity data at cSt@40c and cSt@100c as well as room temperature. This allows ReStackor calculations to reliable scale the effect of fluid viscosities to sub-zero temperatures as well as compute the effect of suspension fade as fluids heat up under hard use. This allows you to design shim stacks to correct for effects of fade as long as a good estimate of the actual working temperature can be made.