CarSpecsHQ

275/40R19 vs 255/50R19

255/50R19 is outside the ±3% rule as a replacement for 275/40R19: the diameter differs by +4.98%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

19" rim
275/40R19 27.66" · 255/50R19 29.04" · drawn to scale

Side by side

275/40R19255/50R19Difference
Overall diameter27.66"29.04"+1.38" (+4.98%)
Section width275 mm255 mm-20 mm
Sidewall4.33"5.02"+0.69"
Rim19"19"same
Circumference86.9"91.2"+4.3"
Revs per mile729695-35
Ride height——+0.69"
Speedometer reads 60 mph60.063.0+3.0 mph

Speedometer and odometer

020406080100120 reads 60 · actual 63.0 mph

With 255/50R19 on a car calibrated for 275/40R19, the speedometer reads 57.2 mph when you're really doing 60, and the odometer under-counts by 5.0%.

Speedo showsActual speed
30 mph31.5 mph
45 mph47.2 mph
60 mph63.0 mph
70 mph73.5 mph
80 mph84.0 mph

Other sizes close to 275/40R19

Questions

Can I replace 275/40R19 with 255/50R19?

255/50R19 is outside the ±3% rule as a replacement for 275/40R19: the diameter differs by +4.98%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

What's the difference between 275/40R19 and 255/50R19?

255/50R19 is 1.38" taller and 20 mm narrower; the sidewall is +0.69". At an indicated 60 mph you'd actually be doing 63.0 mph.

Will 255/50R19 fit on 275/40R19 wheels?

Both use a 19" rim, so the wheel diameter matches; check the wheel's width range for a 255 mm tire and the fender clearance.