CarSpecsHQ

275/35R20 vs 285/35R20

285/35R20 is a safe swap for 275/35R20 by the usual ±3% rule: the diameter differs by +1.00%.

20" rim
275/35R20 27.58" · 285/35R20 27.85" · drawn to scale

Side by side

275/35R20285/35R20Difference
Overall diameter27.58"27.85"+0.28" (+1.00%)
Section width275 mm285 mm+10 mm
Sidewall3.79"3.93"+0.14"
Rim20"20"same
Circumference86.6"87.5"+0.9"
Revs per mile731724-7
Ride height——+0.14"
Speedometer reads 60 mph60.060.6+0.6 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.6 mph

With 285/35R20 on a car calibrated for 275/35R20, the speedometer reads 59.4 mph when you're really doing 60, and the odometer under-counts by 1.0%.

Speedo showsActual speed
30 mph30.3 mph
45 mph45.4 mph
60 mph60.6 mph
70 mph70.7 mph
80 mph80.8 mph

Other sizes close to 275/35R20

Questions

Can I replace 275/35R20 with 285/35R20?

285/35R20 is a safe swap for 275/35R20 by the usual ±3% rule: the diameter differs by +1.00%.

What's the difference between 275/35R20 and 285/35R20?

285/35R20 is 0.28" taller and 10 mm wider; the sidewall is +0.14". At an indicated 60 mph you'd actually be doing 60.6 mph.

Will 285/35R20 fit on 275/35R20 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.