CarSpecsHQ

285/50R20 vs 245/60R20

245/60R20 is a safe swap for 285/50R20 by the usual ±3% rule: the diameter differs by +1.13%.

20" rim
285/50R20 31.22" · 245/60R20 31.57" · drawn to scale

Side by side

285/50R20245/60R20Difference
Overall diameter31.22"31.57"+0.35" (+1.13%)
Section width285 mm245 mm-40 mm
Sidewall5.61"5.79"+0.18"
Rim20"20"same
Circumference98.1"99.2"+1.1"
Revs per mile646639-7
Ride height——+0.18"
Speedometer reads 60 mph60.060.7+0.7 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.7 mph

With 245/60R20 on a car calibrated for 285/50R20, the speedometer reads 59.3 mph when you're really doing 60, and the odometer under-counts by 1.1%.

Speedo showsActual speed
30 mph30.3 mph
45 mph45.5 mph
60 mph60.7 mph
70 mph70.8 mph
80 mph80.9 mph

Other sizes close to 285/50R20

Questions

Can I replace 285/50R20 with 245/60R20?

245/60R20 is a safe swap for 285/50R20 by the usual ±3% rule: the diameter differs by +1.13%.

What's the difference between 285/50R20 and 245/60R20?

245/60R20 is 0.35" taller and 40 mm narrower; the sidewall is +0.18". At an indicated 60 mph you'd actually be doing 60.7 mph.

Will 245/60R20 fit on 285/50R20 wheels?

Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 245 mm tire and the fender clearance.