CarSpecsHQ

245/30R20 vs 225/35R20

225/35R20 is a safe swap for 245/30R20 by the usual ±3% rule: the diameter differs by +1.60%.

20" rim
245/30R20 25.79" · 225/35R20 26.20" · drawn to scale

Side by side

245/30R20225/35R20Difference
Overall diameter25.79"26.20"+0.41" (+1.60%)
Section width245 mm225 mm-20 mm
Sidewall2.89"3.10"+0.21"
Rim20"20"same
Circumference81.0"82.3"+1.3"
Revs per mile782770-12
Ride height——+0.21"
Speedometer reads 60 mph60.061.0+1.0 mph

Speedometer and odometer

020406080100120 reads 60 · actual 61.0 mph

With 225/35R20 on a car calibrated for 245/30R20, the speedometer reads 59.1 mph when you're really doing 60, and the odometer under-counts by 1.6%.

Speedo showsActual speed
30 mph30.5 mph
45 mph45.7 mph
60 mph61.0 mph
70 mph71.1 mph
80 mph81.3 mph

Other sizes close to 245/30R20

Questions

Can I replace 245/30R20 with 225/35R20?

225/35R20 is a safe swap for 245/30R20 by the usual ±3% rule: the diameter differs by +1.60%.

What's the difference between 245/30R20 and 225/35R20?

225/35R20 is 0.41" taller and 20 mm narrower; the sidewall is +0.21". At an indicated 60 mph you'd actually be doing 61.0 mph.

Will 225/35R20 fit on 245/30R20 wheels?

Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 225 mm tire and the fender clearance.