CarSpecsHQ

215/50R18 vs 225/50R18

225/50R18 is a safe swap for 215/50R18 by the usual ±3% rule: the diameter differs by +1.49%.

18" rim
215/50R18 26.46" · 225/50R18 26.86" · drawn to scale

Side by side

215/50R18225/50R18Difference
Overall diameter26.46"26.86"+0.39" (+1.49%)
Section width215 mm225 mm+10 mm
Sidewall4.23"4.43"+0.20"
Rim18"18"same
Circumference83.1"84.4"+1.2"
Revs per mile762751-11
Ride height——+0.20"
Speedometer reads 60 mph60.060.9+0.9 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.9 mph

With 225/50R18 on a car calibrated for 215/50R18, the speedometer reads 59.1 mph when you're really doing 60, and the odometer under-counts by 1.5%.

Speedo showsActual speed
30 mph30.4 mph
45 mph45.7 mph
60 mph60.9 mph
70 mph71.0 mph
80 mph81.2 mph

Other sizes close to 215/50R18

Questions

Can I replace 215/50R18 with 225/50R18?

225/50R18 is a safe swap for 215/50R18 by the usual ±3% rule: the diameter differs by +1.49%.

What's the difference between 215/50R18 and 225/50R18?

225/50R18 is 0.39" taller and 10 mm wider; the sidewall is +0.20". At an indicated 60 mph you'd actually be doing 60.9 mph.

Will 225/50R18 fit on 215/50R18 wheels?

Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 225 mm tire and the fender clearance.