CarSpecsHQ

295/45R20 vs 255/55R20

255/55R20 is a safe swap for 295/45R20 by the usual ±3% rule: the diameter differs by +1.94%.

20" rim
295/45R20 30.45" · 255/55R20 31.04" · drawn to scale

Side by side

295/45R20255/55R20Difference
Overall diameter30.45"31.04"+0.59" (+1.94%)
Section width295 mm255 mm-40 mm
Sidewall5.23"5.52"+0.30"
Rim20"20"same
Circumference95.7"97.5"+1.9"
Revs per mile662650-13
Ride height——+0.30"
Speedometer reads 60 mph60.061.2+1.2 mph

Speedometer and odometer

020406080100120 reads 60 · actual 61.2 mph

With 255/55R20 on a car calibrated for 295/45R20, the speedometer reads 58.9 mph when you're really doing 60, and the odometer under-counts by 1.9%.

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 295/45R20

Questions

Can I replace 295/45R20 with 255/55R20?

255/55R20 is a safe swap for 295/45R20 by the usual ±3% rule: the diameter differs by +1.94%.

What's the difference between 295/45R20 and 255/55R20?

255/55R20 is 0.59" taller and 40 mm narrower; the sidewall is +0.30". At an indicated 60 mph you'd actually be doing 61.2 mph.

Will 255/55R20 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.