CarSpecsHQ

295/45R20 vs 255/60R20

255/60R20 is outside the ±3% rule as a replacement for 295/45R20: the diameter differs by +5.24%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

20" rim
295/45R20 30.45" · 255/60R20 32.05" · drawn to scale

Side by side

295/45R20255/60R20Difference
Overall diameter30.45"32.05"+1.59" (+5.24%)
Section width295 mm255 mm-40 mm
Sidewall5.23"6.02"+0.80"
Rim20"20"same
Circumference95.7"100.7"+5.0"
Revs per mile662629-33
Ride height——+0.80"
Speedometer reads 60 mph60.063.1+3.1 mph

Speedometer and odometer

020406080100120 reads 60 · actual 63.1 mph

With 255/60R20 on a car calibrated for 295/45R20, the speedometer reads 57.0 mph when you're really doing 60, and the odometer under-counts by 5.2%.

Speedo showsActual speed
30 mph31.6 mph
45 mph47.4 mph
60 mph63.1 mph
70 mph73.7 mph
80 mph84.2 mph

Other sizes close to 295/45R20

Questions

Can I replace 295/45R20 with 255/60R20?

255/60R20 is outside the ±3% rule as a replacement for 295/45R20: the diameter differs by +5.24%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

What's the difference between 295/45R20 and 255/60R20?

255/60R20 is 1.59" taller and 40 mm narrower; the sidewall is +0.80". At an indicated 60 mph you'd actually be doing 63.1 mph.

Will 255/60R20 fit on 295/45R20 wheels?

Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 255 mm tire and the fender clearance.