CarSpecsHQ

275/30R20 vs 275/35R20

275/35R20 is outside the ±3% rule as a replacement for 275/30R20: the diameter differs by +4.09%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

20" rim
275/30R20 26.50" · 275/35R20 27.58" · drawn to scale

Side by side

275/30R20275/35R20Difference
Overall diameter26.50"27.58"+1.08" (+4.09%)
Section width275 mm275 mm0 mm
Sidewall3.25"3.79"+0.54"
Rim20"20"same
Circumference83.2"86.6"+3.4"
Revs per mile761731-30
Ride height——+0.54"
Speedometer reads 60 mph60.062.5+2.5 mph

Speedometer and odometer

020406080100120 reads 60 · actual 62.5 mph

With 275/35R20 on a car calibrated for 275/30R20, the speedometer reads 57.6 mph when you're really doing 60, and the odometer under-counts by 4.1%.

Speedo showsActual speed
30 mph31.2 mph
45 mph46.8 mph
60 mph62.5 mph
70 mph72.9 mph
80 mph83.3 mph

Other sizes close to 275/30R20

Questions

Can I replace 275/30R20 with 275/35R20?

275/35R20 is outside the ±3% rule as a replacement for 275/30R20: the diameter differs by +4.09%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

What's the difference between 275/30R20 and 275/35R20?

275/35R20 is 1.08" taller and 0 mm wider; the sidewall is +0.54". At an indicated 60 mph you'd actually be doing 62.5 mph.

Will 275/35R20 fit on 275/30R20 wheels?

Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 275 mm tire and the fender clearance.