CarSpecsHQ

275/40R19 vs 285/45R19

285/45R19 is outside the ±3% rule as a replacement for 275/40R19: the diameter differs by +5.19%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

19" rim
275/40R19 27.66" · 285/45R19 29.10" · drawn to scale

Side by side

275/40R19285/45R19Difference
Overall diameter27.66"29.10"+1.44" (+5.19%)
Section width275 mm285 mm+10 mm
Sidewall4.33"5.05"+0.72"
Rim19"19"same
Circumference86.9"91.4"+4.5"
Revs per mile729693-36
Ride height——+0.72"
Speedometer reads 60 mph60.063.1+3.1 mph

Speedometer and odometer

020406080100120 reads 60 · actual 63.1 mph

With 285/45R19 on a car calibrated for 275/40R19, the speedometer reads 57.0 mph when you're really doing 60, and the odometer under-counts by 5.2%.

Speedo showsActual speed
30 mph31.6 mph
45 mph47.3 mph
60 mph63.1 mph
70 mph73.6 mph
80 mph84.2 mph

Other sizes close to 275/40R19

Questions

Can I replace 275/40R19 with 285/45R19?

285/45R19 is outside the ±3% rule as a replacement for 275/40R19: the diameter differs by +5.19%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

What's the difference between 275/40R19 and 285/45R19?

285/45R19 is 1.44" taller and 10 mm wider; the sidewall is +0.72". At an indicated 60 mph you'd actually be doing 63.1 mph.

Will 285/45R19 fit on 275/40R19 wheels?

Both use a 19" rim, so the wheel diameter matches; check the wheel's width range for a 285 mm tire and the fender clearance.