CarSpecsHQ

245/55R18 vs 225/60R18

225/60R18 is a safe swap for 245/55R18 by the usual ±3% rule: the diameter differs by +0.07%.

18" rim
245/55R18 28.61" · 225/60R18 28.63" · drawn to scale

Side by side

245/55R18225/60R18Difference
Overall diameter28.61"28.63"+0.02" (+0.07%)
Section width245 mm225 mm-20 mm
Sidewall5.31"5.31"+0.01"
Rim18"18"same
Circumference89.9"89.9"+0.1"
Revs per mile705704-0
Ride height——+0.01"
Speedometer reads 60 mph60.060.0+0.0 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.0 mph

With 225/60R18 on a car calibrated for 245/55R18, the speedometer reads 60.0 mph when you're really doing 60, and the odometer under-counts by 0.1%.

Speedo showsActual speed
30 mph30.0 mph
45 mph45.0 mph
60 mph60.0 mph
70 mph70.0 mph
80 mph80.1 mph

Other sizes close to 245/55R18

Questions

Can I replace 245/55R18 with 225/60R18?

225/60R18 is a safe swap for 245/55R18 by the usual ±3% rule: the diameter differs by +0.07%.

What's the difference between 245/55R18 and 225/60R18?

225/60R18 is 0.02" taller and 20 mm narrower; the sidewall is +0.01". At an indicated 60 mph you'd actually be doing 60.0 mph.

Will 225/60R18 fit on 245/55R18 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.