SpringSpec

SpringSpec is a specialist spring rate calculator for motorsport suspension, built by race engineers for race engineers.

Enter your corner weights, unsprung mass, and motion ratio — SpringSpec calculates wheel frequency, wheel rate, critical damping, and static deflection across every standard spring rate. It then recommends Soft, Recommended, and Hard options based on your intended use and drivetrain layout, and matches you to real parts from the Eibach ERS and Hyperco catalogues.

WHAT IT DOES

- Dual-axle calculator — front and rear, together, with frequency, wheel rate, damping and deflection for every common spring rate
- Drivetrain-aware balance — Front-engine RWD, Mid/Rear-engine RWD, Front-wheel Drive
- Target frequency presets from Road (1.3 Hz) to Race (2.2 Hz), plus custom entry
- Motion ratio entered as a decimal, squared internally — the correct engineering convention used by every serious damper manufacturer
- Colour-coded frequency bands (Road, Road/Track, Race, Too Hard) so you can see at a glance what a given spring will do to the car
- Built-in catalogue lookup for Eibach ERS and Hyperco springs, filtered by target rate, free length, ID, and travel required
- Motion Ratio Guide — two measurement methods explained clearly, with diagrams
- Save customer jobs locally with full inputs, results, and notes — perfect for race engineers managing multiple cars
- Works in lbs/in, N/mm, or kg/mm — switch units any time

WHO IT'S FOR

Race engineers. Trackday drivers dialling in a new setup. Suspension specialists selecting springs for customers. Tuners replacing OE springs with something proper. Anyone who's ever stared at a spreadsheet trying to work out what spring rate they actually need for their car.

THE PRINCIPLES

No accounts. No cloud. No ads. No subscriptions. No tracking.

Every calculation, every saved job, every piece of data stays on your device. SpringSpec never sends anything to the internet. There is no backend server — this app was engineered to work in a workshop, pit-side, or at the kitchen table with zero connectivity.

One-off purchase. Updates via Google Play when verified data is added.

IMPORTANT

SpringSpec provides engineering guidance based on the data you enter. Always verify inputs and outputs independently against manufacturer specifications. Suspension setup affects vehicle handling and safety — verify setup choices with a qualified motorsport engineer where appropriate.

Published by RaceTracs Ltd, United Kingdom.

Recent changes:
NEW — Dual Rate Calculator: model main + tender spring stacks (coil bind or lockout collar), with combined rate, crossover point, installed lengths, travel remaining, preload, ride-height window, and setup warnings. Save and reload complete setups.