Automotive Calculator by F2

Automotive Calculator by F2 is a collection of practical automotive calculators designed for tire shops, wheel retailers, automotive parts stores, trailer businesses and vehicle enthusiasts.

The app helps customers compare tire sizes, understand wheel offset changes, check tire and wheel fitment, estimate towing capacity, calculate trailer payload and calculate gear ratios directly from your Shopify storefront.

Installation Guide

Step 1 — Install the App

Install Automotive Calculator by F2 from the Shopify App Store.

After installation, open the app from your Shopify Admin.

Step 2 — Open Your Theme

Go to:

Shopify Admin → Online Store → Themes → Customize

Select the theme where you want to display the calculator.

Step 3 — Add an App Block

Open the page or section where you want to display a calculator.

Click:

Add section / Add block → Apps

Then select the required calculator from Automotive Calculator by F2.

Each calculator is an independent Theme App Extension block.

Step 4 — Select a Calculator

The app includes:

• Tire Size Calculator
• Wheel Offset Calculator
• Tire & Wheel Fitment Calculator
• Towing Capacity Calculator
• Trailer Weight & Payload Calculator
• Gear Ratio Calculator

Step 5 — Configure the Block

After adding the calculator, use the Shopify Theme Editor to configure the available settings.

You can customize available:

• Heading
• Description
• Labels
• Units
• Default values
• Result display
• CTA
• Colors
• Typography
• Layout
• Disclaimer
• Other appearance options

Step 6 — Save & Test

Click Save and open the storefront.

Enter realistic vehicle values and verify that the calculator produces the expected results.

Calculator Block Guide

01 — Tire Size Calculator

Compare a vehicle’s current tire size with a new tire size.

Customers Can Enter

• Current tire width
• Current aspect ratio
• Current rim diameter
• New tire width
• New aspect ratio
• New rim diameter

Calculates

• Sidewall height
• Overall diameter
• Circumference
• Diameter difference
• Circumference difference
• Percentage difference
• Speedometer difference estimate
• Revolutions per distance

For example, customers can compare 225/45R18 with 235/40R19.

Best For

Tire shops, wheel stores and automotive parts retailers.

02 — Wheel Offset Calculator

The Wheel Offset Calculator helps customers understand how changing wheel width and offset can affect wheel position.

Customers Can Compare

• Current wheel width
• Current offset
• New wheel width
• New offset

Helps Estimate

• Inner position change
• Outer position change
• Wheel width difference
• Offset difference

For example:

8J ET35 → 9J ET45

can be compared to understand the resulting wheel-position change.

Best For

Wheel retailers, performance shops and custom vehicle businesses.

03 — Tire & Wheel Fitment Calculator

The Tire & Wheel Fitment Calculator helps customers compare tire and wheel combinations before purchasing.

Customers Can Review

• Tire width
• Aspect ratio
• Rim diameter
• Wheel width
• Offset
• Overall size relationship

Purpose

It provides an easy way to compare the selected tire/wheel combination and understand dimensional changes.

Best For

Performance shops, tire retailers and custom wheel stores.

Fitment results are estimates and should be verified against the vehicle manufacturer’s specifications and available clearance.

04 — Towing Capacity Calculator

The Towing Capacity Calculator helps customers estimate available towing capacity and trailer weight.

Customers Can Enter

• Vehicle towing capacity
• Vehicle GVWR
• Curb weight
• Passenger weight
• Cargo weight
• Trailer empty weight
• Trailer cargo weight
• Tongue weight percentage

Calculates

• Available towing capacity
• Total trailer weight
• Combined vehicle/trailer weight
• Payload used
• Remaining towing capacity
• Remaining payload

Status

The result can indicate:

WITHIN LIMIT

NEAR LIMIT

OVER LIMIT

The calculator is designed to provide estimates from entered values and is not presented as manufacturer-certified safety approval.

05 — Trailer Weight & Payload Calculator

This calculator helps customers estimate trailer loading and remaining payload capacity.

Customers Can Enter

• Trailer GVWR
• Trailer empty weight
• Cargo weight
• Additional equipment
• Additional passenger/load
• Hitch or tongue weight
• Unit

Calculates

• Gross Trailer Weight
• Payload Capacity
• Payload Used
• Remaining Payload
• Percentage Used
• Over-capacity status

Supported Units

• lb
• kg

The calculator includes visual status indicators such as Available, Near Limit and Over Limit.

06 — Gear Ratio Calculator

The Gear Ratio Calculator helps automotive users calculate drivetrain gearing, estimated speed and RPM.

Customers Can Enter

• Engine RPM
• Transmission gear ratio
• Final drive ratio
• Tire diameter
• Tire unit
• Vehicle speed
• Speed unit
• Gear selection where applicable

Calculates

• Gear ratio
• Overall ratio
• Estimated speed
• Estimated RPM

The core relationship uses:

Overall Ratio = Transmission Gear Ratio × Final Drive Ratio

Vehicle speed is calculated using engine RPM, tire diameter and overall ratio.

Supported Units

Speed: mph / km/h

Tire diameter: inch / mm / cm

Automotive Safety Information

For safety-related calculators such as Towing Capacity, Payload and Fitment, results should be treated as estimates.

Customers should verify:

• Manufacturer ratings
• Vehicle specifications
• Hitch rating
• Axle rating
• Tongue-weight requirements
• Tire load rating
• Wheel specifications
• Applicable regulations

The calculator should not be treated as manufacturer-certified safety approval. The project specification explicitly requires manufacturer-specification verification for these calculators.

Merchant Tips

1. Use accurate vehicle/product specifications.
2. Set appropriate default values.
3. Select the correct measurement units.
4. Place each calculator close to relevant products.
5. Test calculations using known vehicle examples.
6. Verify tire and wheel specifications before publishing.
7. Use safety disclaimers for towing and fitment calculators.
8. Use CTA buttons to guide customers toward relevant products.
9. Test each calculator on mobile and desktop.
10. Save and preview the theme after making changes.

Quick Installation Summary

Install App
     ↓
Online Store
     ↓
Themes
     ↓
Customize
     ↓
Add Block / Add Section
     ↓
Apps
     ↓
Automotive Calculator by F2
     ↓
Select Calculator
     ↓
Configure Settings
     ↓
Save
     ↓
Test Storefront