CarSpecsHQ

315/30R19 vs 345/30R19

345/30R19 is a safe swap for 315/30R19 by the usual ±3% rule: the diameter differs by +2.68%.

19" rim
315/30R19 26.44" · 345/30R19 27.15" · drawn to scale

Side by side

315/30R19345/30R19Difference
Overall diameter26.44"27.15"+0.71" (+2.68%)
Section width315 mm345 mm+30 mm
Sidewall3.72"4.07"+0.35"
Rim19"19"same
Circumference83.1"85.3"+2.2"
Revs per mile763743-20
Ride height——+0.35"
Speedometer reads 60 mph60.061.6+1.6 mph

Speedometer and odometer

020406080100120 reads 60 · actual 61.6 mph

With 345/30R19 on a car calibrated for 315/30R19, the speedometer reads 58.4 mph when you're really doing 60, and the odometer under-counts by 2.7%.

Speedo showsActual speed
30 mph30.8 mph
45 mph46.2 mph
60 mph61.6 mph
70 mph71.9 mph
80 mph82.1 mph

Other sizes close to 315/30R19

Questions

Can I replace 315/30R19 with 345/30R19?

345/30R19 is a safe swap for 315/30R19 by the usual ±3% rule: the diameter differs by +2.68%.

What's the difference between 315/30R19 and 345/30R19?

345/30R19 is 0.71" taller and 30 mm wider; the sidewall is +0.35". At an indicated 60 mph you'd actually be doing 61.6 mph.

Will 345/30R19 fit on 315/30R19 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.