CarSpecsHQ

225/45R19 vs 345/30R19

345/30R19 is a safe swap for 225/45R19 by the usual ±3% rule: the diameter differs by +0.66%.

19" rim
225/45R19 26.97" · 345/30R19 27.15" · drawn to scale

Side by side

225/45R19345/30R19Difference
Overall diameter26.97"27.15"+0.18" (+0.66%)
Section width225 mm345 mm+120 mm
Sidewall3.99"4.07"+0.09"
Rim19"19"same
Circumference84.7"85.3"+0.6"
Revs per mile748743-5
Ride height——+0.09"
Speedometer reads 60 mph60.060.4+0.4 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.4 mph

With 345/30R19 on a car calibrated for 225/45R19, the speedometer reads 59.6 mph when you're really doing 60, and the odometer under-counts by 0.7%.

Speedo showsActual speed
30 mph30.2 mph
45 mph45.3 mph
60 mph60.4 mph
70 mph70.5 mph
80 mph80.5 mph

Other sizes close to 225/45R19

Questions

Can I replace 225/45R19 with 345/30R19?

345/30R19 is a safe swap for 225/45R19 by the usual ±3% rule: the diameter differs by +0.66%.

What's the difference between 225/45R19 and 345/30R19?

345/30R19 is 0.18" taller and 120 mm wider; the sidewall is +0.09". At an indicated 60 mph you'd actually be doing 60.4 mph.

Will 345/30R19 fit on 225/45R19 wheels?

Both use a 19" rim, so the wheel diameter matches; check the wheel's width range for a 345 mm tire and the fender clearance.