Shim Calculator Engineering

Engineering-grade shim-stack analysis for modern workshops, tuners, and race teams.
Fork + Shock Professional Suite

All the depth of legacy damping tools, rebuilt for modern tuning workflows.

Shim Calculator Engineering combines serious suspension physics with a clean browser interface, so you can tune faster, explain decisions with confidence, and deliver repeatable, report-ready results to customers and teams.

Physics First
Flow-path simulation with piston, base, and mid-valve interaction instead of simple stack guessing.
Platform Coverage
Supports KYB/Showa/WP forks and monotube or twin-tube shock architectures in one environment.
Engineer Visibility
Inspect pressure, force, shim lift, flow split, cavitation margin, and spring/chamber progression.
Commercial Advantage
Overlay dyno CSV data, compare model vs measured behavior, and justify recommendations clearly.
Start with the demo setup, import dyno data, and build customer-ready valving recommendations backed by transparent assumptions.

Inputs

Fork mode: air-fork platform and chamber fields are visible.
Medium (50%)
Applies to crossover-capable presets (enduro fork/shock). Lower = softer crossover, higher = firmer crossover.
A/B compare inactive
Targets are saved in your browser and drive the green/yellow badge logic.
Architecture and platform
Hydraulic geometry
Flow paths and adjusters
Fork cartridge details
Fluid properties
Spring and travel
Chassis geometry
Air spring reverse engineering (fork)
Reservoir and gas model (shock)
Advanced limits and clamp
Future model input (next phase): ICS / bladder pressure dynamics and cartridge preload recommendation logic.
Dia
Thk
Qty
Excel-style: Enter/Tab/comma auto-advance to next cell. Hidden raw field kept for compatibility.
Dia
Thk
Qty
Same spreadsheet behavior as compression.
Dia
Thk
Qty
Dia
Thk
Qty
CSV must include headers with velocity and force columns. Direction column is optional.

Unlock Calculated Shim Stacks

USD $100.00 / analysis
Enter all setup details first, then complete payment to reveal calculated stacks and full engineering outputs.
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Live engineering view
Pressure-flow opening equilibrium
0.30 m/s focus
Base valve
Compression zeta
-
Target 0.54
Rebound zeta
-
Target 0.39
Main port area mm2
-
Target 120.8 mm2
Cavitation margin bar
-
Target >= 1.00 bar
Payment required
Complete USD $100.00 PayPal payment to unlock the live engineering simulation and charts.

Engineering summary

Machine / platform-
Active target profile-
Main port area-
Base / mid port area-
Bleed / rebound area-
Piston bleed hole area-
Mid float / trampoline preload-
Critical damping-
Compression force @ 0.3-
Rebound force @ 0.3-
Main / bypass flow @ 0.3-
Piston shim lift @ 0.3-
Reservoir pressure probe-
Cavitation margin @ 0.3-
Spring end pressure-
Chassis measurements
Trail-
Effective rake-
Chassis pitch-
Swingarm angle-
Chain angle-
Anti-squat proxy-
Static weight split F/R-
Wheel rate F/R-
Handling flags-
WP AER equivalent rate-
WP AER equivalent preload-
Required psi for target rate-
Shim stacks
Input Compression
Locked until payment
Recommended Compression
Locked until payment
Input Rebound
Locked until payment
Recommended Rebound
Locked until payment
Complete payment to reveal calculated recommendations.
Calculated stacks are locked
Pay USD $100.00 via PayPal to unlock recommended shim stacks and full analysis outputs.
Charts locked
Unlock charts and computed stack recommendations after PayPal payment confirmation.
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