CarSpecsHQ

335/25R20 vs 305/30R20

305/30R20 is a safe swap for 335/25R20 by the usual ±3% rule: the diameter differs by +2.29%.

20" rim
335/25R20 26.59" · 305/30R20 27.20" · drawn to scale

Side by side

335/25R20305/30R20Difference
Overall diameter26.59"27.20"+0.61" (+2.29%)
Section width335 mm305 mm-30 mm
Sidewall3.30"3.60"+0.31"
Rim20"20"same
Circumference83.5"85.5"+1.9"
Revs per mile758741-17
Ride height——+0.31"
Speedometer reads 60 mph60.061.4+1.4 mph

Speedometer and odometer

020406080100120 reads 60 · actual 61.4 mph

With 305/30R20 on a car calibrated for 335/25R20, the speedometer reads 58.7 mph when you're really doing 60, and the odometer under-counts by 2.3%.

Speedo showsActual speed
30 mph30.7 mph
45 mph46.0 mph
60 mph61.4 mph
70 mph71.6 mph
80 mph81.8 mph

Other sizes close to 335/25R20

Questions

Can I replace 335/25R20 with 305/30R20?

305/30R20 is a safe swap for 335/25R20 by the usual ±3% rule: the diameter differs by +2.29%.

What's the difference between 335/25R20 and 305/30R20?

305/30R20 is 0.61" taller and 30 mm narrower; the sidewall is +0.31". At an indicated 60 mph you'd actually be doing 61.4 mph.

Will 305/30R20 fit on 335/25R20 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.