245/75R16 vs 265/75R16
Switching from 245/75R16 to 265/75R16 changes the overall diameter by +30.0 mm (+3.9%) — outside the commonly used ±3% guideline. Every figure below is calculated from the two size codes with the standard formulas.
| Measurement | 245/75R16 | 265/75R16 | Difference |
|---|---|---|---|
| Overall diameter | 773.9 mm | 803.9 mm | +30.0 mm (+3.9%) |
| Overall diameter | 30.47 in | 31.65 in | +1.18 in |
| Tire width | 245 mm (9.65 in) | 265 mm (10.43 in) | +20 mm |
| Sidewall height | 183.8 mm (7.23 in) | 198.8 mm (7.82 in) | +15.0 mm |
| Wheel (rim) diameter | 16.0 in | 16.0 in | 0.0 in |
| Circumference | 2431 mm | 2526 mm | +94 mm |
| Revolutions per mile | 2080 | 2002 | -78 |
| Revolutions per km | 411 | 396 | -15 |
Speedometer error
Calibrated for 245/75R16, the speedometer under-reads or over-reads once 265/75R16 is fitted. This is your real speed at each indicated speed:
| Speedometer shows | Actual speed on 265/75R16 | Error |
|---|---|---|
| 20 mph | 20.8 mph | +0.8 mph |
| 40 mph | 41.6 mph | +1.6 mph |
| 60 mph | 62.3 mph | +2.3 mph |
| 80 mph | 83.1 mph | +3.1 mph |
| 100 mph | 103.9 mph | +3.9 mph |
How these two sizes are worked out
245/75R16 breaks down as a 245 mm tread width with a sidewall of 75% of that width (183.8 mm) on a 16.0-inch wheel, giving an overall diameter of 773.9 mm (30.47 in). 265/75R16 works out to 803.9 mm (31.65 in) the same way. The standard formulas are the same ones used on the tire size calculator page: diameter = rim × 25.4 + 2 × sidewall, circumference = π × diameter, revolutions per mile = 63,360 ÷ diameter in inches.
Nominal sizes vary slightly between brands and models, and tread wear shrinks a tire over its life. These figures follow the size codes exactly; your vehicle manual or a professional tire shop is the authority for what fits your vehicle.
More comparisons
Frequently asked questions
Can I replace 245/75R16 tires with 265/75R16?
The diameter change is +3.9%, which is outside the commonly used ±3% guideline. Diameter is only one part of fitment — wheel width range, load index, speed rating and physical clearance all have to check out too, so confirm with your vehicle manual or a professional tire shop before buying.
Will 265/75R16 make my speedometer read wrong?
Yes, by the diameter ratio. When the dial shows 60 mph you are really doing 62.3 mph on 265/75R16. The full table above covers 20 to 100 mph.
Which tire is taller, 245/75R16 or 265/75R16?
265/75R16 is taller — 803.9 mm against 773.9 mm overall diameter, a difference of 30.0 mm.