305/45R22 vs 275/50R22

Q: Can I replace 305/45R22 with 275/50R22?

275/50R22 is a safe swap for 305/45R22 by the usual ±3% rule: the diameter differs by +0.06%.

275/50R22 is a safe swap for 305/45R22 by the usual ±3% rule: the diameter differs by +0.06%.

305/45R22 32.81" · 275/50R22 32.83" · drawn to scale

Side by side

	305/45R22	275/50R22	Difference
Overall diameter	32.81"	32.83"	+0.02" (+0.06%)
Section width	305 mm	275 mm	-30 mm
Sidewall	5.40"	5.41"	+0.01"
Rim	22"	22"	same
Circumference	103.1"	103.1"	+0.1"
Revs per mile	615	614	-0
Ride height	—	—	+0.01"
Speedometer reads 60 mph	60.0	60.0	+0.0 mph

Speedometer and odometer

With 275/50R22 on a car calibrated for 305/45R22, the speedometer reads 60.0 mph when you're really doing 60, and the odometer under-counts by 0.1%.

Speedo shows	Actual speed
30 mph	30.0 mph
45 mph	45.0 mph
60 mph	60.0 mph
70 mph	70.0 mph
80 mph	80.0 mph

Other sizes close to 305/45R22

Questions

Can I replace 305/45R22 with 275/50R22?

275/50R22 is a safe swap for 305/45R22 by the usual ±3% rule: the diameter differs by +0.06%.

What's the difference between 305/45R22 and 275/50R22?

275/50R22 is 0.02" taller and 30 mm narrower; the sidewall is +0.01". At an indicated 60 mph you'd actually be doing 60.0 mph.

Will 275/50R22 fit on 305/45R22 wheels?

Both use a 22" rim, so the wheel diameter matches; check the wheel's width range for a 275 mm tire and the fender clearance.