Tools in This Collection
Tire Size Calculator
Compare tire sizes and check speedometer error percentage
Tire Pressure Chart
Find correct tire pressure for your vehicle and load
Wheel Offset Calculator
Calculate how offset changes affect wheel position
Brake Pad Life Calculator
Estimate remaining brake pad life by thickness and mileage
Oil Change Interval Calculator
Find oil change interval based on oil type and conditions
Car Detailing Cost Estimator
Estimate detailing cost by service level and vehicle size
Car Wrap Calculator
Estimate vinyl wrap material cost for full or partial wraps
Window Tint Calculator
Calculate window tinting cost by window count and film type
Tire and Maintenance Calculation Workflow
Tires and maintenance are the most common areas where car owners make costly mistakes — either by installing incompatible tire sizes, getting poor-fitting wheels, or ignoring maintenance intervals that accelerate wear. These tools make the math clear before you spend money.
Reading and Decoding Tire Sizes
The sidewall code on a P225/65R17 tire breaks down as: P = passenger vehicle, 225 = section width in millimeters, 65 = aspect ratio (sidewall height is 65% of 225mm = 146mm), R = radial construction, 17 = rim diameter in inches. The Tire Size Calculator compares current and proposed sizes to show the diameter difference, speedometer error percentage, and whether the tires will fit your wheel wells.
Plus-Sizing and Wheel Fitment
Plus-sizing (going wider with a lower aspect ratio) keeps the overall tire diameter similar while improving handling with a wider contact patch. Going from P225/65R17 to P235/55R18 (plus-one sizing) increases width by 10mm, reduces sidewall height, and moves to an 18-inch rim while keeping total diameter within 1%. The Tire Size Calculator shows all these values so you can verify clearance before purchasing.
Wheel Offset and Fitment
The Wheel Offset Calculator determines how a wheel's offset affects its lateral position in the wheel well. Positive offset pushes the wheel inward (toward the suspension); negative offset pushes it outward. Changing from +40mm to +25mm offset moves the wheel face 15mm outward — potentially rubbing the fender on suspension travel. The calculator shows the exact position change for any offset swap.
Brake and Oil Maintenance
The Brake Pad Life Calculator estimates remaining pad life as a percentage based on current thickness versus new (typically 10-12mm) and your annual mileage. At 2mm remaining out of a new 10mm pad, you have 20% life left — roughly the point where replacement should be scheduled. The Oil Change Interval Calculator accounts for oil type (conventional changes at 3,000-5,000 miles, synthetic at 7,500-10,000 miles), engine age, and driving conditions (city stop-and-go degrades oil faster than highway driving).
Detailing and Appearance Costs
The Car Detailing Cost Estimator estimates total detailing expense for different service levels — basic wash and wax ($50-100) versus full paint correction and ceramic coating ($800-2,500). The Car Wrap Calculator estimates material cost for a full or partial vehicle wrap based on vehicle size, and the Window Tint Calculator estimates tinting cost by window count and film type.
Frequently Asked Questions
How do I read a tire size like P225/65R17?
P = passenger vehicle type. 225 = section width in millimeters (tread width). 65 = aspect ratio — sidewall height is 65% of 225mm, which is 146mm tall. R = radial construction. 17 = rim diameter in inches that the tire fits. The Tire Size Calculator decodes any tire size and compares it against alternatives to check compatibility.
What is wheel offset and why does it matter?
Wheel offset is the distance from the wheel's mounting face to its centerline. Positive offset (+40mm) pushes the wheel inward toward the engine. Negative offset (-10mm) pushes it outward toward the fender. Changing offset affects clearance against suspension components and fender liners. The Wheel Offset Calculator shows exactly how far the wheel moves for any offset change.
How often should I change my oil with synthetic vs conventional?
Conventional oil is typically changed every 3,000-5,000 miles or 3 months. Full synthetic oil can go 7,500-10,000 miles or 6-12 months in most modern engines. Severe driving conditions (lots of short trips, extreme temperatures, towing) require shorter intervals regardless of oil type. The Oil Change Interval Calculator accounts for your specific driving conditions and oil type.
When should I replace my brake pads?
Brake pads should be replaced when they reach 2-3mm thickness — most new pads start at 10-12mm. At 2mm, the wear indicator may start squealing. At 1mm or less, metal-on-metal contact damages rotors, turning a $100 pad replacement into a $400 rotor replacement. The Brake Pad Life Calculator estimates how many miles remain based on current thickness and your typical annual mileage.