275/40R17 vs 225/50R17

Q: Can I replace 275/40R17 with 225/50R17?

225/50R17 is a safe swap for 275/40R17 by the usual ±3% rule: the diameter differs by +0.77%.

225/50R17 is a safe swap for 275/40R17 by the usual ±3% rule: the diameter differs by +0.77%.

275/40R17 25.66" · 225/50R17 25.86" · drawn to scale

Side by side

	275/40R17	225/50R17	Difference
Overall diameter	25.66"	25.86"	+0.20" (+0.77%)
Section width	275 mm	225 mm	-50 mm
Sidewall	4.33"	4.43"	+0.10"
Rim	17"	17"	same
Circumference	80.6"	81.2"	+0.6"
Revs per mile	786	780	-6
Ride height	—	—	+0.10"
Speedometer reads 60 mph	60.0	60.5	+0.5 mph

Speedometer and odometer

With 225/50R17 on a car calibrated for 275/40R17, the speedometer reads 59.5 mph when you're really doing 60, and the odometer under-counts by 0.8%.

Speedo shows	Actual speed
30 mph	30.2 mph
45 mph	45.3 mph
60 mph	60.5 mph
70 mph	70.5 mph
80 mph	80.6 mph

Other sizes close to 275/40R17

Questions

Can I replace 275/40R17 with 225/50R17?

225/50R17 is a safe swap for 275/40R17 by the usual ±3% rule: the diameter differs by +0.77%.

What's the difference between 275/40R17 and 225/50R17?

225/50R17 is 0.20" taller and 50 mm narrower; the sidewall is +0.10". At an indicated 60 mph you'd actually be doing 60.5 mph.

Will 225/50R17 fit on 275/40R17 wheels?

Both use a 17" rim, so the wheel diameter matches; check the wheel's width range for a 225 mm tire and the fender clearance.