GarageCalc Can You Use 225 Tires Instead of 215?
Compare 215 and 225 tire widths with complete size examples, diameter changes and the fitment checks to make before buying replacement tires.
17 vs 18 Inch Wheels: Compare the Whole Tire
See how 17 and 18 inch wheels change tire sidewall height in a matched-size example, plus the clearance, cost and comfort questions to check.
Do Bigger Tires Affect Your Speedometer?
Calculate how a tire diameter change affects indicated speed, odometer distance and MPG, with a worked example and a speed comparison table.
Wheel Offset vs Backspacing: Measurements & Math
Understand wheel offset and backspacing with a measurement diagram, an inch-to-mm conversion table and a worked wheel-width comparison.
Payload vs Towing Capacity: Check Both Limits
Learn how payload, towing capacity, GVWR and GCWR interact using a worked passenger, cargo and tongue-weight example for a conventional trailer.
How Much Does a Car Depreciate per Year?
Separate observed car depreciation from forecast assumptions, calculate annual value loss and compare a five-year example with published market data.
What Is Combined MPG? City vs Highway Explained
Learn how EPA combined MPG uses city and highway driving, why a simple MPG average is wrong, and how to estimate fuel use for your own driving mix.
Tire Rotation Patterns: FWD, RWD, AWD and Directional Tires
See tire rotation diagrams for FWD, RWD, AWD and directional tires, plus the exceptions that change the pattern and when to rotate.
ABS Light Meaning: What to Do When It Stays On
A steady ABS warning means anti-lock braking may be unavailable. Learn how it differs from a red brake warning and when to stop or seek service.
Looking for a sidewall marking or fuel calculation?
Start with the tire size decoder, DOT date code guide, load index chart or fill-up MPG calculator.