CarSpecsHQ

225/35R20 vs 285/30R20

285/30R20 is a safe swap for 225/35R20 by the usual ±3% rule: the diameter differs by +2.03%.

20" rim
225/35R20 26.20" · 285/30R20 26.73" · drawn to scale

Side by side

225/35R20285/30R20Difference
Overall diameter26.20"26.73"+0.53" (+2.03%)
Section width225 mm285 mm+60 mm
Sidewall3.10"3.37"+0.27"
Rim20"20"same
Circumference82.3"84.0"+1.7"
Revs per mile770754-15
Ride height——+0.27"
Speedometer reads 60 mph60.061.2+1.2 mph

Speedometer and odometer

020406080100120 reads 60 · actual 61.2 mph

With 285/30R20 on a car calibrated for 225/35R20, the speedometer reads 58.8 mph when you're really doing 60, and the odometer under-counts by 2.0%.

Speedo showsActual speed
30 mph30.6 mph
45 mph45.9 mph
60 mph61.2 mph
70 mph71.4 mph
80 mph81.6 mph

Other sizes close to 225/35R20

Questions

Can I replace 225/35R20 with 285/30R20?

285/30R20 is a safe swap for 225/35R20 by the usual ±3% rule: the diameter differs by +2.03%.

What's the difference between 225/35R20 and 285/30R20?

285/30R20 is 0.53" taller and 60 mm wider; the sidewall is +0.27". At an indicated 60 mph you'd actually be doing 61.2 mph.

Will 285/30R20 fit on 225/35R20 wheels?

Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 285 mm tire and the fender clearance.