CarSpecsHQ

265/45R18 vs 275/40R19

275/40R19 is a safe swap for 265/45R18 by the usual ±3% rule: the diameter differs by +0.99%.

18" → 19"
265/45R18 27.39" · 275/40R19 27.66" · drawn to scale

Side by side

265/45R18275/40R19Difference
Overall diameter27.39"27.66"+0.27" (+0.99%)
Section width265 mm275 mm+10 mm
Sidewall4.69"4.33"-0.36"
Rim18"19"+1"
Circumference86.0"86.9"+0.9"
Revs per mile736729-7
Ride height——+0.14"
Speedometer reads 60 mph60.060.6+0.6 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.6 mph

With 275/40R19 on a car calibrated for 265/45R18, the speedometer reads 59.4 mph when you're really doing 60, and the odometer under-counts by 1.0%.

Speedo showsActual speed
30 mph30.3 mph
45 mph45.4 mph
60 mph60.6 mph
70 mph70.7 mph
80 mph80.8 mph

Other sizes close to 265/45R18

Questions

Can I replace 265/45R18 with 275/40R19?

275/40R19 is a safe swap for 265/45R18 by the usual ±3% rule: the diameter differs by +0.99%.

What's the difference between 265/45R18 and 275/40R19?

275/40R19 is 0.27" taller and 10 mm wider; the sidewall is -0.36". At an indicated 60 mph you'd actually be doing 60.6 mph.

Will 275/40R19 fit on 265/45R18 wheels?

No — 265/45R18 needs a 18" wheel and 275/40R19 a 19" wheel. This is a plus/minus-size swap that changes wheels too.