CarSpecsHQ

245/40R17 vs 225/50R16

225/50R16 is a safe swap for 245/40R17 by the usual ±3% rule: the diameter differs by +0.57%.

17" → 16"
245/40R17 24.72" · 225/50R16 24.86" · drawn to scale

Side by side

245/40R17225/50R16Difference
Overall diameter24.72"24.86"+0.14" (+0.57%)
Section width245 mm225 mm-20 mm
Sidewall3.86"4.43"+0.57"
Rim17"16"-1"
Circumference77.6"78.1"+0.4"
Revs per mile816811-5
Ride height——+0.07"
Speedometer reads 60 mph60.060.3+0.3 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.3 mph

With 225/50R16 on a car calibrated for 245/40R17, the speedometer reads 59.7 mph when you're really doing 60, and the odometer under-counts by 0.6%.

Speedo showsActual speed
30 mph30.2 mph
45 mph45.3 mph
60 mph60.3 mph
70 mph70.4 mph
80 mph80.5 mph

Other sizes close to 245/40R17

Questions

Can I replace 245/40R17 with 225/50R16?

225/50R16 is a safe swap for 245/40R17 by the usual ±3% rule: the diameter differs by +0.57%.

What's the difference between 245/40R17 and 225/50R16?

225/50R16 is 0.14" taller and 20 mm narrower; the sidewall is +0.57". At an indicated 60 mph you'd actually be doing 60.3 mph.

Will 225/50R16 fit on 245/40R17 wheels?

No — 245/40R17 needs a 17" wheel and 225/50R16 a 16" wheel. This is a plus/minus-size swap that changes wheels too.