Tire Size Box

265/70R15 vs 265/80R15

265/80R15 compared with 265/70R15

+7.0% diameter, 0.0" width

265/80R15 is 31.69" tall vs 29.61". More than the 3% rule of thumb, so check carefully before switching.

29.6"15" rim7.3"10.4" wide
265/70R15 (solid) compared with 265/80R15 (dashed outline), drawn to scale

With 265/80R15 tires, when your speedometer says 60 mph you are really going

64.2 mph

265/80R15 is +2.09 inches (+7.0%) in overall diameter. That is more than the 3% most shops and makers recommend.

265/70R15265/80R15Difference%
Overall diameter29.61"31.69"+2.09"+7.0%
Section width10.43"10.43"0.00"0.0%
Sidewall height7.30"8.35"+1.04"+14.3%
Circumference93.01"99.57"+6.56"+7.0%
Revolutions per mile681.2636.4−44.8−6.6%

Speedometer difference

If your vehicle came with 265/70R15 and you fit 265/80R15, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.4 mph+1.4 mph
30 mph32.1 mph+2.1 mph
40 mph42.8 mph+2.8 mph
50 mph53.5 mph+3.5 mph
60 mph64.2 mph+4.2 mph
65 mph69.6 mph+4.6 mph
70 mph74.9 mph+4.9 mph
75 mph80.3 mph+5.3 mph
80 mph85.6 mph+5.6 mph

Each size on its own

Questions

Which is bigger, 265/70R15 or 265/80R15?
265/80R15 is taller by 2.09 inches (31.69" vs 29.61"). 265/70R15 is the same width.
Can I replace 265/70R15 with 265/80R15?
It is not recommended without checking carefully. The diameter difference is +7.0%, more than the 3% most shops and makers allow. It will throw off the speedometer and may affect ABS, stability control and clearance.
How much will 265/80R15 change my speedometer?
When your speedometer reads 60 mph with 265/80R15 fitted (calibrated for 265/70R15), your real speed is 64.2 mph. Your odometer will under-count miles by about 7.0%.
Will 265/80R15 lift my vehicle?
Ride height changes by half the diameter difference: +1.04 inches of ground clearance at the axle.

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