CarSpecsHQ

225/40R19 vs 225/45R19

225/45R19 is outside the ±3% rule as a replacement for 225/40R19: the diameter differs by +3.40%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

19" rim
225/40R19 26.09" · 225/45R19 26.97" · drawn to scale

Side by side

225/40R19225/45R19Difference
Overall diameter26.09"26.97"+0.89" (+3.40%)
Section width225 mm225 mm0 mm
Sidewall3.54"3.99"+0.44"
Rim19"19"same
Circumference82.0"84.7"+2.8"
Revs per mile773748-25
Ride height——+0.44"
Speedometer reads 60 mph60.062.0+2.0 mph

Speedometer and odometer

020406080100120 reads 60 · actual 62.0 mph

With 225/45R19 on a car calibrated for 225/40R19, the speedometer reads 58.0 mph when you're really doing 60, and the odometer under-counts by 3.4%.

Speedo showsActual speed
30 mph31.0 mph
45 mph46.5 mph
60 mph62.0 mph
70 mph72.4 mph
80 mph82.7 mph

Other sizes close to 225/40R19

Questions

Can I replace 225/40R19 with 225/45R19?

225/45R19 is outside the ±3% rule as a replacement for 225/40R19: the diameter differs by +3.40%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

What's the difference between 225/40R19 and 225/45R19?

225/45R19 is 0.89" taller and 0 mm wider; the sidewall is +0.44". At an indicated 60 mph you'd actually be doing 62.0 mph.

Will 225/45R19 fit on 225/40R19 wheels?

Both use a 19" rim, so the wheel diameter matches; check the wheel's width range for a 225 mm tire and the fender clearance.