245/65R17 vs 265/65R17
Switching from 245/65R17 to 265/65R17 changes the overall diameter by +26.0 mm (+3.5%) — outside the commonly used ±3% guideline. Every figure below is calculated from the two size codes with the standard formulas.
| Measurement | 245/65R17 | 265/65R17 | Difference |
|---|---|---|---|
| Overall diameter | 750.3 mm | 776.3 mm | +26.0 mm (+3.5%) |
| Overall diameter | 29.54 in | 30.56 in | +1.02 in |
| Tire width | 245 mm (9.65 in) | 265 mm (10.43 in) | +20 mm |
| Sidewall height | 159.3 mm (6.27 in) | 172.3 mm (6.78 in) | +13.0 mm |
| Wheel (rim) diameter | 17.0 in | 17.0 in | 0.0 in |
| Circumference | 2357 mm | 2439 mm | +82 mm |
| Revolutions per mile | 2145 | 2073 | -72 |
| Revolutions per km | 424 | 410 | -14 |
Speedometer error
Calibrated for 245/65R17, the speedometer under-reads or over-reads once 265/65R17 is fitted. This is your real speed at each indicated speed:
| Speedometer shows | Actual speed on 265/65R17 | Error |
|---|---|---|
| 20 mph | 20.7 mph | +0.7 mph |
| 40 mph | 41.4 mph | +1.4 mph |
| 60 mph | 62.1 mph | +2.1 mph |
| 80 mph | 82.8 mph | +2.8 mph |
| 100 mph | 103.5 mph | +3.5 mph |
How these two sizes are worked out
245/65R17 breaks down as a 245 mm tread width with a sidewall of 65% of that width (159.3 mm) on a 17.0-inch wheel, giving an overall diameter of 750.3 mm (29.54 in). 265/65R17 works out to 776.3 mm (30.56 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 245/65R17 tires with 265/65R17?
The diameter change is +3.5%, 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 265/65R17 make my speedometer read wrong?
Yes, by the diameter ratio. When the dial shows 60 mph you are really doing 62.1 mph on 265/65R17. The full table above covers 20 to 100 mph.
Which tire is taller, 245/65R17 or 265/65R17?
265/65R17 is taller — 776.3 mm against 750.3 mm overall diameter, a difference of 26.0 mm.