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Tire Size Comparator
Compare metric or flotation tire sizes, geometry, diameter change, and speedometer error.
Frequently asked questions
What does 265/70R17 mean?
265 is section width in millimeters, 70 is sidewall height as a percentage of width, and 17 is wheel diameter in inches.
What does 33x12.50R17 mean?
It is flotation notation: approximately 33 inches overall diameter, 12.50 inches section width, and a 17-inch wheel.
Why is a 3% diameter change commonly used?
It is a screening rule for speedometer, gearing, clearance, and electronic-system changes—not a guarantee that a tire fits or is approved.
How is speedometer error calculated?
Actual speed equals indicated speed multiplied by new tire diameter divided by original tire diameter.
Does matching diameter guarantee fitment?
No. Width, wheel offset, load rating, suspension clearance, brake clearance, and manufacturer approvals still matter.