305/45R22 vs 285/50R22

Q: Can I replace 305/45R22 with 285/50R22?

285/50R22 is a safe swap for 305/45R22 by the usual ±3% rule: the diameter differs by +1.26%.

285/50R22 is a safe swap for 305/45R22 by the usual ±3% rule: the diameter differs by +1.26%.

305/45R22 32.81" · 285/50R22 33.22" · drawn to scale

Side by side

	305/45R22	285/50R22	Difference
Overall diameter	32.81"	33.22"	+0.41" (+1.26%)
Section width	305 mm	285 mm	-20 mm
Sidewall	5.40"	5.61"	+0.21"
Rim	22"	22"	same
Circumference	103.1"	104.4"	+1.3"
Revs per mile	615	607	-8
Ride height	—	—	+0.21"
Speedometer reads 60 mph	60.0	60.8	+0.8 mph

Speedometer and odometer

With 285/50R22 on a car calibrated for 305/45R22, the speedometer reads 59.3 mph when you're really doing 60, and the odometer under-counts by 1.3%.

Speedo shows	Actual speed
30 mph	30.4 mph
45 mph	45.6 mph
60 mph	60.8 mph
70 mph	70.9 mph
80 mph	81.0 mph

Other sizes close to 305/45R22

Questions

Can I replace 305/45R22 with 285/50R22?

285/50R22 is a safe swap for 305/45R22 by the usual ±3% rule: the diameter differs by +1.26%.

What's the difference between 305/45R22 and 285/50R22?

285/50R22 is 0.41" taller and 20 mm narrower; the sidewall is +0.21". At an indicated 60 mph you'd actually be doing 60.8 mph.

Will 285/50R22 fit on 305/45R22 wheels?

Both use a 22" rim, so the wheel diameter matches; check the wheel's width range for a 285 mm tire and the fender clearance.