Getting Started with PCD Fitment

PCD Fitment is a web-based tool that helps you convert bolt patterns, match aftermarket wheels, and analyze fitment. There is no software to install—just open your browser and go.

Accessing the app

Visit https://pcdfitment.codecide.net. The app runs entirely in your browser; all your data stays on your device unless you choose to enable encrypted storage.

Quick start: load a demo

The fastest way to see what PCD Fitment can do is to load a pre-built demo scenario. When you first open the app, a Load Demo button appears in the header. Click it to open the demo picker.

Choose one of the five scenarios:

Demo Vehicle What it demonstrates
Toyota Corolla 2018 Corolla Exact bolt pattern match and direct fit
VW Golf 2015 Golf Near-match warning (5×112 vs 5×114.3)
BMW 3 Series 2020 330i Hub-ring requirement and offset detail
Jeep Wrangler 2021 Wrangler Adapter required / safety notes
Ford F-150 2019 F-150 Full 6-lug analysis with vibration risk

Each demo fills the appropriate inputs and runs the analysis automatically. You can explore the results, then switch to any tab to see the raw data or modify values and see the report update.

To clear a demo and start fresh, open Settings (gear icon) and choose Clear all data.

Core interface walkthrough

After loading (or skipping) the demo, you see the main screen with these elements:

  1. Header: app name, settings button, password-lock icon (if encryption is enabled), and a unit toggle.
  2. Tab bar: five tabs—Converter, Measurer, Reference, Fitment, Garage.
  3. Main content area: displays the active tool.
  4. Feedback button (bottom right): opens a form to report bugs, request features, or give general input.

Unit toggle

Click the mm/in button in the header to switch the display units globally. All future inputs are interpreted in the selected system, and all outputs adapt accordingly.

App lock (optional)

If you want to protect your saved vehicle profiles, click the shield icon (or the first-run welcome screen) to enable AES-256-GCM encryption. You create a password, and from then on your garage data is encrypted in your browser’s storage. If you forget your password, the data cannot be recovered. The app lock only protects locally stored profiles—conversions and measurements are never stored.

Using the tools

1. Converter

The Converter accepts a bolt pattern string and instantly converts it between metric (mm) and imperial (inches). It also classifies the pattern as an exact match to a known standard, a near-match, or incompatible.

To use it:

  • Type a bolt pattern such as 5x114.3, 5 on 4.5, or 5 4 1/2 into the text field.
  • The app parses the input, detects the unit automatically, and shows the converted value.
  • A copy button lets you copy the result.

The conversion factor (25.4 mm = 1 inch) is always exact. The result also includes a match classification that warns you about ambiguous patterns (e.g., 5×112 vs 5×114.3).

2. Measurer

The Measurer computes PCD from a physical measurement between studs. This is useful when you have a hub in front of you and want to identify its bolt pattern.

To use it:

  • Select the number of lugs (3, 4, 5, 6, 8, or 10).
  • Enter the measured distance between two studs. For 3-lug and 5-lug patterns, measure adjacent studs. For even counts (4, 6, 8, 10), measure opposite studs.
  • The engine calculates the bolt circle diameter and shows the closest known pattern, confidence level, and any ambiguity warnings.

If the distance falls into an "ambiguity zone" where two patterns are less than 3 mm apart, the tool flags it for manual verification.

3. Fitment

Fitment performs a full aftermarket wheel analysis. You provide your vehicle’s factory specs and the proposed wheel specs; the app checks pattern compatibility, hub-ring need, offset suitability, adapter thickness, and vibration risk.

To use it:

  • Select a vehicle from the built-in database (make, model, year). The app fills in all factory specs automatically.
  • Enter the aftermarket wheel details: bolt pattern (lug count and PCD), center bore, offset (ET), and wheel width.
  • The report appears with several expandable sections:
    • Pattern match: exact, near-match, or incompatible.
    • Hub ring: whether a hub-centric ring is required and its dimensions.
    • Adapter analysis: minimum thickness, resulting offset, and safety notes if an adapter is needed.
    • Offset & backspacing: conversion between ET and backspacing.
    • Vibration risk: a score based on PCD delta and stud count, plus explanatory notes.

If you leave the vehicle field empty (or select “none”), the analysis compares only against generic standards and assumes an incompatible fit.

4. Reference

The Reference tab lets you browse the known PCD database without entering any measurements. You can explore patterns by manufacturer, lug count, or region. It also displays hardware specs (stud thread size, seat type, and torque values).

5. Garage

Save vehicles you own or work with frequently. Click Add Vehicle and enter the specs manually or import them from the Fitment tab. Saved profiles persist across sessions and are encrypted if you enabled app lock. You can later select a garage vehicle directly from the Fitment vehicle picker.

Next steps

  • Explore each tab to get comfortable with the conversions and analysis.
  • Use the Feedback button if something looks off or you have an idea for improvement.
  • For programmatic access, PCD Fitment also provides a REST API and an MCP server that let you integrate the calculation engine into your own tools.