Tire Size Box

265/75R15 vs 265/85R15

265/85R15 compared with 265/75R15

+6.8% diameter, 0.0" width

265/85R15 is 32.74" tall vs 30.65". More than the 3% rule of thumb, so check carefully before switching.

30.6"15" rim7.8"10.4" wide
265/75R15 (solid) compared with 265/85R15 (dashed outline), drawn to scale

With 265/85R15 tires, when your speedometer says 60 mph you are really going

64.1 mph

265/85R15 is +2.09 inches (+6.8%) in overall diameter. That is more than the 3% most shops and makers recommend.

265/75R15265/85R15Difference%
Overall diameter30.65"32.74"+2.09"+6.8%
Section width10.43"10.43"0.00"0.0%
Sidewall height7.82"8.87"+1.04"+13.3%
Circumference96.29"102.84"+6.56"+6.8%
Revolutions per mile658.0616.1−41.9−6.4%

Speedometer difference

If your vehicle came with 265/75R15 and you fit 265/85R15, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.4 mph+1.4 mph
30 mph32.0 mph+2.0 mph
40 mph42.7 mph+2.7 mph
50 mph53.4 mph+3.4 mph
60 mph64.1 mph+4.1 mph
65 mph69.4 mph+4.4 mph
70 mph74.8 mph+4.8 mph
75 mph80.1 mph+5.1 mph
80 mph85.4 mph+5.4 mph

Each size on its own

Questions

Which is bigger, 265/75R15 or 265/85R15?
265/85R15 is taller by 2.09 inches (32.74" vs 30.65"). 265/75R15 is the same width.
Can I replace 265/75R15 with 265/85R15?
It is not recommended without checking carefully. The diameter difference is +6.8%, 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 265/85R15 change my speedometer?
When your speedometer reads 60 mph with 265/85R15 fitted (calibrated for 265/75R15), your real speed is 64.1 mph. Your odometer will under-count miles by about 6.8%.
Will 265/85R15 lift my vehicle?
Ride height changes by half the diameter difference: +1.04 inches of ground clearance at the axle.

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