CarSpecsHQ

285/35R18 vs 225/50R17

225/50R17 is a safe swap for 285/35R18 by the usual ±3% rule: the diameter differs by +0.02%.

18" → 17"
285/35R18 25.85" · 225/50R17 25.86" · drawn to scale

Side by side

285/35R18225/50R17Difference
Overall diameter25.85"25.86"+0.00" (+0.02%)
Section width285 mm225 mm-60 mm
Sidewall3.93"4.43"+0.50"
Rim18"17"-1"
Circumference81.2"81.2"+0.0"
Revs per mile780780-0
Ride height——+0.00"
Speedometer reads 60 mph60.060.0+0.0 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.0 mph

With 225/50R17 on a car calibrated for 285/35R18, the speedometer reads 60.0 mph when you're really doing 60, and the odometer under-counts by 0.0%.

Speedo showsActual speed
30 mph30.0 mph
45 mph45.0 mph
60 mph60.0 mph
70 mph70.0 mph
80 mph80.0 mph

Other sizes close to 285/35R18

Questions

Can I replace 285/35R18 with 225/50R17?

225/50R17 is a safe swap for 285/35R18 by the usual ±3% rule: the diameter differs by +0.02%.

What's the difference between 285/35R18 and 225/50R17?

225/50R17 is 0.00" taller and 60 mm narrower; the sidewall is +0.50". At an indicated 60 mph you'd actually be doing 60.0 mph.

Will 225/50R17 fit on 285/35R18 wheels?

No — 285/35R18 needs a 18" wheel and 225/50R17 a 17" wheel. This is a plus/minus-size swap that changes wheels too.