CarSpecsHQ

175/70R14 vs 225/50R15

225/50R15 is a safe swap for 175/70R14 by the usual ±3% rule: the diameter differs by +0.90%.

14" → 15"
175/70R14 23.65" · 225/50R15 23.86" · drawn to scale

Side by side

175/70R14225/50R15Difference
Overall diameter23.65"23.86"+0.21" (+0.90%)
Section width175 mm225 mm+50 mm
Sidewall4.82"4.43"-0.39"
Rim14"15"+1"
Circumference74.3"75.0"+0.7"
Revs per mile853845-8
Ride height——+0.11"
Speedometer reads 60 mph60.060.5+0.5 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.5 mph

With 225/50R15 on a car calibrated for 175/70R14, the speedometer reads 59.5 mph when you're really doing 60, and the odometer under-counts by 0.9%.

Speedo showsActual speed
30 mph30.3 mph
45 mph45.4 mph
60 mph60.5 mph
70 mph70.6 mph
80 mph80.7 mph

Other sizes close to 175/70R14

Questions

Can I replace 175/70R14 with 225/50R15?

225/50R15 is a safe swap for 175/70R14 by the usual ±3% rule: the diameter differs by +0.90%.

What's the difference between 175/70R14 and 225/50R15?

225/50R15 is 0.21" taller and 50 mm wider; the sidewall is -0.39". At an indicated 60 mph you'd actually be doing 60.5 mph.

Will 225/50R15 fit on 175/70R14 wheels?

No — 175/70R14 needs a 14" wheel and 225/50R15 a 15" wheel. This is a plus/minus-size swap that changes wheels too.