265/65R18 vs 275/65R18

275/65R18 is 0.5" taller than 265/65R18 (1.6%)

Diameter difference+1.62%diameter 31.56" → 32.07"
265/65R18275/65R18
265/65R18275/65R18Difference
Overall diameter31.56"32.07"+0.51"
Section width10.43"10.83"+0.39"
Sidewall height6.78"7.04"+0.26"
Circumference99.2"100.8"+1.6"
Revolutions per mile639629−10
Wheel diameter18"18"±0"

Speedometer

ShowsActualDiff
30 mph30.5 mph+0.5
45 mph45.7 mph+0.7
60 mph61.0 mph+1.0
70 mph71.1 mph+1.1
80 mph81.3 mph+1.3

Gear ratio to match

CurrentEquivalent
3.423.48
3.553.61
3.733.79
4.104.17

275/65R18 is 0.51" taller than 265/65R18, a +1.62% change in diameter, inside the 3% range most shops treat as a safe swap.

Ground clearance changes by 0.26" (half the diameter change), and the tire needs 0.26" more 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 0.26" taller on 275/65R18.

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

FAQ

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

275/65R18 is 0.51" taller (+1.62%) and 0.39" wider than 265/65R18.

Will 275/65R18 change my speedometer?

Yes, by +1.62%. When the speedometer shows 60 mph you would be going 61.0 mph.

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

Often yes: the diameter change of +1.6% is within the common 3% guideline. Check the load index, speed rating and clearance.