205/50R16 vs 205/45R17

Q: Can I replace 205/50R16 with 205/45R17?

205/45R17 is a safe swap for 205/50R16 by the usual ±3% rule: the diameter differs by +0.80%.

205/45R17 is a safe swap for 205/50R16 by the usual ±3% rule: the diameter differs by +0.80%.

205/50R16 24.07" · 205/45R17 24.26" · drawn to scale

Side by side

	205/50R16	205/45R17	Difference
Overall diameter	24.07"	24.26"	+0.19" (+0.80%)
Section width	205 mm	205 mm	0 mm
Sidewall	4.04"	3.63"	-0.40"
Rim	16"	17"	+1"
Circumference	75.6"	76.2"	+0.6"
Revs per mile	838	831	-7
Ride height	—	—	+0.10"
Speedometer reads 60 mph	60.0	60.5	+0.5 mph

Speedometer and odometer

With 205/45R17 on a car calibrated for 205/50R16, 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	45.4 mph
60 mph	60.5 mph
70 mph	70.6 mph
80 mph	80.6 mph

Other sizes close to 205/50R16

Questions

Can I replace 205/50R16 with 205/45R17?

205/45R17 is a safe swap for 205/50R16 by the usual ±3% rule: the diameter differs by +0.80%.

What's the difference between 205/50R16 and 205/45R17?

205/45R17 is 0.19" taller and 0 mm wider; the sidewall is -0.40". At an indicated 60 mph you'd actually be doing 60.5 mph.

Will 205/45R17 fit on 205/50R16 wheels?

No — 205/50R16 needs a 16" wheel and 205/45R17 a 17" wheel. This is a plus/minus-size swap that changes wheels too.