CarSpecsHQ

265/45R18 vs 275/45R18

275/45R18 is a safe swap for 265/45R18 by the usual ±3% rule: the diameter differs by +1.29%.

18" rim
265/45R18 27.39" · 275/45R18 27.74" · drawn to scale

Side by side

265/45R18275/45R18Difference
Overall diameter27.39"27.74"+0.35" (+1.29%)
Section width265 mm275 mm+10 mm
Sidewall4.69"4.87"+0.18"
Rim18"18"same
Circumference86.0"87.2"+1.1"
Revs per mile736727-9
Ride height——+0.18"
Speedometer reads 60 mph60.060.8+0.8 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.8 mph

With 275/45R18 on a car calibrated for 265/45R18, the speedometer reads 59.2 mph when you're really doing 60, and the odometer under-counts by 1.3%.

Speedo showsActual speed
30 mph30.4 mph
45 mph45.6 mph
60 mph60.8 mph
70 mph70.9 mph
80 mph81.0 mph

Other sizes close to 265/45R18

Questions

Can I replace 265/45R18 with 275/45R18?

275/45R18 is a safe swap for 265/45R18 by the usual ±3% rule: the diameter differs by +1.29%.

What's the difference between 265/45R18 and 275/45R18?

275/45R18 is 0.35" taller and 10 mm wider; the sidewall is +0.18". At an indicated 60 mph you'd actually be doing 60.8 mph.

Will 275/45R18 fit on 265/45R18 wheels?

Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 275 mm tire and the fender clearance.