Tuning Basics:

  Stack styles

  Damping profiles

  Spring selection

  Spring rate change

Sample Apps:

  Clicker settings

  Oil Viscosity

  Shock Cavitation

  Fork Cavitation

  Weight scaling

  XR650 valving




Sample Applications

  • ReStackor has been purposely designed to be easy to use. 

    • Simple geometric based inputs.

    • Intuitive graphical outputs. 

The sample applications below demonstrate use of both the Shim ReStackor and ReStackor pro to solve practical suspension tuning problems.

Tuning Basics: 

  • Example applications modifying shim stacks and valve port geometries to control suspension response.

  • Spring rate and damping profile tuning.

Sample Apps: 

  • Sample applications of Shim ReStackor and ReStackor pro to solve practical suspension tuning problems.


Tuning Basics:

Shim Stack Styles: 

There are many different styles of shim stacks used in suspension systems. Some of the basic styles are reviewed here along with discussions of the tunable features in each style of shim stack (more)

  • Sample calculation using the demo version of Shim ReStackor and ReStackor pro.

Shock absorber damping profiles: 

Linear; progressive and digressive are the three fundamental damping profiles used in shock absorbers. Features of each style of damping profile are discussed in this thread as well as howto modify the shock absorber valve and shim stack to produce those profiles (more) .

Spring Rate Selection: 

When setting up a suspension weight transfer during turning and acceleration are the primary factors controlling spring selection. This example reviews the effect of spring rate effects on sag, damping and suspension response.  (more) .

Damper tuning for a spring rate change: 

Many riders believe you can add a couple of clicks to the bleed clickers or change the oil viscosity to compensate for a change in spring rate. This ReStackor pro example shows why that does not work (more) .

Sample Applications:

Retune your shim stack to match a specific clicker setting: 

A common tuning problem is needing to "re-center" the clickers to produce a softer or stiffer suspension. This example retunes a stock stack to be three clicks softer by adding a crossover shim and adjusting the stack clamp shim (more)

  • Sample calculation using the demo version in Shim ReStackor mode

Oil Viscosity: Tune your stack to duplicate 5wt oil performance using 10wt oil 

Suppose after putting 5wt fork oil in you bike you fell in love with the feel of the suspension. You want to switch back to 10wt oil but maintain the suspension feel of the lighter weight oil. What changes to the shim stack do you need to make the stack behave like it was working with 5wt oil? (more)

  • Sample calculation using the demo version in ReStackor pro mode


ReStackor pro calculations are capable of determining suspension cavitation limits,  the suspension velocity where cavitation initiates, the magnitude of the cavitation event and the performance of the suspension when driven beyond the cavitation limit. This gives you the capability to tune the stiffness of the base valve shim stack, mid-valve shim stack, mid-valve float and bladder or ICS pressurization system to control cavitation and the suspension performance when driven beyond the cavitation limit. 

Weight Scaling, Correct damping rates for a spring rate change: 

A popular application for Shim ReStackor calculations is scaling of the stock damping rates to correct for a spring rate change. The scaling process restores the balance of weight, spring rate and damping the manufacture intended for the phantom weight of the stock rider. While the calculations may not give you the optimum damping for the speed and terrain that you ride it does provide a solid starting point to begin the tuning process on a new bike. 

A special worksheet is included with the ReStackor demo software for these calculations. This example walks you through the calculations needed to correct for a spring rate change (more) .

  • Sample calculations using the demo version in Shim ReStackor mode

XR650: Borynack Valve Stacks: 

For those of you with an XR650 that have not seen Bruce Borynack's web page let me introduce you. Bruce has several valve stack recommendations for an XR650. A common question is "How do these stacks compare to my stock stack?". This example compares Borynack's stacks to the stock valve stack (more) .

  • Sample calculations using both Shim ReStackor and ReStackor pro

CRF450: Correcting stock damping for a spring rate change:

This example problem applies the baseline Shim ReStackor code to scale the damping rates of the stock suspension to the weight of a heavier rider and retunes the shim stack using the fundamentals of spring-mass-damper theory. (more) .

  • Sample calculations using Shim ReStackor