265/75R18 vs 275/65R18

265/75R18 is 1.6" taller than 275/65R18 (4.7%)

Diameter difference−4.68%diameter 33.65" → 32.07"
265/75R18275/65R18
265/75R18275/65R18Difference
Overall diameter33.65"32.07"−1.57"
Section width10.43"10.83"+0.39"
Sidewall height7.82"7.04"−0.79"
Circumference105.7"100.8"−4.9"
Revolutions per mile599629+29
Wheel diameter18"18"±0"

Speedometer

ShowsActualDiff
30 mph28.6 mph−1.4
45 mph42.9 mph−2.1
60 mph57.2 mph−2.8
70 mph66.7 mph−3.3
80 mph76.3 mph−3.7

Gear ratio to match

CurrentEquivalent
3.423.26
3.553.38
3.733.56
4.103.91

275/65R18 is 1.57" shorter than 265/75R18, a −4.68% change in diameter. That is more than the 3% many tire shops use as a limit, so plan on recalibrating the speedometer and checking ABS and stability control.

Ground clearance changes by 0.79" (half the diameter change), and the tire needs 0.79" less room above it.

275/65R18 is 0.39" wider. On the same wheel offset about half of that, 0.20", moves toward the suspension and half toward the fender.

Both fit a 18" wheel; the sidewall is 0.79" shorter on 275/65R18.

Details: 265/75R18 in inches · 275/65R18 in inches · change sizes in the calculator

FAQ

What is the difference between 265/75R18 and 275/65R18?

275/65R18 is 1.57" shorter (−4.68%) and 0.39" wider than 265/75R18.

Will 275/65R18 change my speedometer?

Yes, by −4.68%. When the speedometer shows 60 mph you would be going 57.2 mph.

Can I replace 265/75R18 with 275/65R18?

It is a −4.7% diameter change, larger than the common 3% guideline, so check clearance and plan to recalibrate.