User Guide – Pressure Balance & Adjuster Authority

This guide explains exactly what to enter, where to get the numbers, and how to interpret the outputs.

Safety & responsibility: This tool is decision-support only. Always confirm with testing, rider feedback, and safety checks.

1) What the Tool Does (in plain English)

Core relationship: Force = Area × Pressure

Your dyno gives you force at given shaft speeds. If you know the correct effective area at the point you care about, you can calculate the corresponding pressure.

The tool also calculates Adjuster Authority — what percentage of your total damping force is actually controlled by the adjuster circuit.

2) Data You Must Have Before You Start

A. Dyno force values (minimum set)

Three velocities (shaft speeds), in m/s. Typical examples: 0.10, 1.00, 2.50 m/s.
Total force at each velocity (N). This is the complete measured damping force for that configuration.
Adjuster-only force at each velocity (N). This is measured with the main stack influence minimised, or by the method you use to isolate the adjuster circuit.

If your dyno exports in mm/s or in lbf, convert first:
• mm/s → m/s: divide by 1000
• lbf → N: multiply by 4.44822

B. Geometry / area inputs

Main piston diameter (mm) — used to estimate main working area.
Rod diameter (mm) — used as an area proxy for balance/adjuster influence (and annulus where relevant).

C. Setup context (recommended)

Oil temperature (approx)
Oil type/viscosity and bleed configuration
Dyno test direction (compression vs rebound) and configuration notes

3) Step-by-Step: How to Use the App

Step 1 — Choose the mode

Open the app and go to Compression tab first (then repeat for Rebound).
Set your velocity reference (v_ref) — usually 1.0 m/s for a meaningful mid-speed reference.

Step 2 — Enter the three velocity points

Enter V1, V2, V3 in m/s (example: 0.10, 1.00, 2.50).
These velocities must match the dyno points you measured.

Step 3 — Enter force values at each velocity

Enter Adj-only F1/F2/F3 (N) — adjuster circuit contribution.
Enter Full F1/F2/F3 (N) — total damping force.

Tip: Keep signs consistent (some dynos output compression/rebound as negative/positive). Use magnitudes if you’re comparing authority and targets.

Step 4 — Enter geometry (area proxies)

Piston/body diameter (mm) — main area proxy.
Rod diameter (mm) — rod/annulus and balance influence proxy.

Step 5 — Check the Adjuster Authority band

The app calculates authority at your v_ref:

Adj % = (Adjuster-only force / Total force) × 100

Recommended authority range (typical):

15–20% is an ideal range for meaningful adjustment (good authority without excessive risk).
< 15% often feels like “the clicker doesn’t do much” because the adjuster circuit contributes too little.
> 20% increases risk of cavitation/hysteresis and may require higher pressures to stabilise.
6–8% may indicate a highly pressure-balanced condition where adjuster change range becomes very small.

Step 6 — Review the graphs

Adjuster Damping vs Velocity — shows adjuster-only force curve.
Total Damping vs Velocity — shows full force curve.
Recommended band/targets — highlights whether you are under/over the desired range.

Step 7 — Repeat for Rebound

Enter rebound dyno points in the Rebound tab.
Compare how authority differs between compression and rebound.

Step 8 — Use Compare & Export

Compare overlays key metrics (authority and/or curves).
Export downloads a CSV for job records, customer notes, or build tracking.

4) What the Readings Mean

Adjuster-only force (N)

The portion of measured damping attributable to the adjuster-controlled flow path (bleed/needle/HSC circuit depending on test method).

Total force (N)

The complete measured damping force at that shaft speed. Includes shim stacks, bleed, piston port effects, and any interaction with the adjuster circuit.

Adjuster Authority (%)

How “powerful” the adjuster is in the overall damping system. If the authority is very low, click changes may be hard to feel because the main piston/stack dominates.

Pressure calculations (where used)

When the tool converts force to pressure, the quality depends on using the correct effective area. Different points in the system can have different effective areas depending on piston/rod/annulus and which side is being considered.

5) Practical Troubleshooting

“My clicker doesn’t do anything”

Check authority at 1.0 m/s. If it’s < 15%, the adjuster contribution may be too small.
Consider mechanical changes to increase adjuster circuit contribution (within safe bounds).

“Authority is too high”

If > 20%, risk of cavitation/hysteresis rises.
You may need more stabilising pressure or circuit changes to reduce dependence on adjuster path.

“Dyno points don’t look smooth”

Confirm consistent oil temperature and test configuration.
Confirm units (mm/s vs m/s, lbf vs N).
Re-run with consistent bleed/click positions.

6) Data Recording Template (recommended)

Record these each session:

Bike / shock or fork model, piston diameter, rod diameter
Oil type and temperature
Clicker settings
V1/V2/V3 and adj-only + total forces
Any stack changes
Rider notes after testing

Pressure Balance & Adjuster Authority Tool