# SpringSpec — Spring Rate Calculator

> Spring Rate Calculator (iPhone/iPad app by RaceTracs Ltd.)

- Source: https://appshunter.io/ios/app/springspec/id6763006520 (this page in markdown: same URL + `.md`)
- Developer: [RaceTracs Ltd](https://appshunter.io/developer/1852276263)
- Category: Utilities, Sports
- Price: $9.99
- Age rating: 4+
- Requires: iOS 15.0 · 3 MB
- Languages: American English
- Released: 2026-04-22
- Data updated: 2026-07-30
- User reviews in markdown: https://appshunter.io/ios/app/springspec/id6763006520/reviews.md

## What is 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.

KEY FEATURES

— Dual-axle calculator with frequency, wheel rate, damping and deflection for every common spring rate
— Drivetrain-aware balance: front-engine RWD, mid/rear-engine RWD, FWD
— Target presets from Road to Race (1.3 Hz to 2.2 Hz) plus custom entry
— Motion ratio entered as a decimal, squared internally — the correct engineering convention
— Colour-coded frequency bands (Road, Road/Track, Race, Too Hard)
— Built-in catalogue lookup for Eibach ERS and Hyperco springs, filtered by rate, free length, ID, and travel
— Motion Ratio Guide with clear diagrams and two measurement methods
— Save customer jobs locally with full inputs, results, and notes
— Works in lbs/in, N/mm, or kg/mm

NO ACCOUNTS. NO CLOUD. NO ADS. NO SUBSCRIPTIONS.
All your data stays on your device. One-off purchase, updates via the App Store.

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

Published by RaceTracs Ltd, United Kingdom.


## Version history (last 5 releases)

### V2.0 — 2026-07-28

NEW — Dual Rate Calculator
Model two springs in series (main + tender/helper) and see exactly how the stack behaves on the car. Supports both coil-bind and lockout-collar setups. Enter your spring rates, free lengths, block heights, corner weight and motion ratio, and SpringSpec calculates the combined rate, the rate at ride height, where the crossover happens and what the rate becomes after it, installed lengths, remaining travel, preload effects, and your workable ride-height window — with clear warnings when a combination won't work (springs going loose, coil bind inside the stroke, helper needed). Includes platform wind-down guidance and save/load for complete setups.

### 1.1.1 — 2026-05-14

Bug fix to contain App to screen size.

### 1.1 — 2026-05-09

Fixed for iOS 26.4.2

### 1.0.2 — 2026-05-01

Version 1.0.2

- Fixed drivetrain frequency balance logic — FWD and Mid/Rear-engine RWD layouts now correctly apply stiffer rear frequency targets, giving more accurate spring rate recommendations for these drivetrain types.

### 1.0 — 2026-04-22

No release notes.

## More apps by RaceTracs Ltd

- [RaceTracs](https://appshunter.io/ios/app/racetracs/id6755153259)
- [StringAlignPro](https://appshunter.io/ios/app/stringalignpro/id6780426421)
- [SevenSense](https://appshunter.io/ios/app/sevensense/id6790457945)

All apps by RaceTracs Ltd: https://appshunter.io/developer/1852276263

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-07-30.*