CarSpecsHQ

295/55R20 vs 305/55R20

305/55R20 is a safe swap for 295/55R20 by the usual ±3% rule: the diameter differs by +1.32%.

20" rim
295/55R20 32.78" · 305/55R20 33.21" · drawn to scale

Side by side

295/55R20305/55R20Difference
Overall diameter32.78"33.21"+0.43" (+1.32%)
Section width295 mm305 mm+10 mm
Sidewall6.39"6.60"+0.22"
Rim20"20"same
Circumference103.0"104.3"+1.4"
Revs per mile615607-8
Ride height——+0.22"
Speedometer reads 60 mph60.060.8+0.8 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.8 mph

With 305/55R20 on a car calibrated for 295/55R20, the speedometer reads 59.2 mph when you're really doing 60, and the odometer under-counts by 1.3%.

Speedo showsActual speed
30 mph30.4 mph
45 mph45.6 mph
60 mph60.8 mph
70 mph70.9 mph
80 mph81.1 mph

Other sizes close to 295/55R20

Questions

Can I replace 295/55R20 with 305/55R20?

305/55R20 is a safe swap for 295/55R20 by the usual ±3% rule: the diameter differs by +1.32%.

What's the difference between 295/55R20 and 305/55R20?

305/55R20 is 0.43" taller and 10 mm wider; the sidewall is +0.22". At an indicated 60 mph you'd actually be doing 60.8 mph.

Will 305/55R20 fit on 295/55R20 wheels?

Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 305 mm tire and the fender clearance.