CarSpecsHQ

255/35R19 vs 315/30R19

315/30R19 is a safe swap for 255/35R19 by the usual ±3% rule: the diameter differs by +1.59%.

19" rim
255/35R19 26.03" · 315/30R19 26.44" · drawn to scale

Side by side

255/35R19315/30R19Difference
Overall diameter26.03"26.44"+0.41" (+1.59%)
Section width255 mm315 mm+60 mm
Sidewall3.51"3.72"+0.21"
Rim19"19"same
Circumference81.8"83.1"+1.3"
Revs per mile775763-12
Ride height——+0.21"
Speedometer reads 60 mph60.061.0+1.0 mph

Speedometer and odometer

020406080100120 reads 60 · actual 61.0 mph

With 315/30R19 on a car calibrated for 255/35R19, 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 255/35R19

Questions

Can I replace 255/35R19 with 315/30R19?

315/30R19 is a safe swap for 255/35R19 by the usual ±3% rule: the diameter differs by +1.59%.

What's the difference between 255/35R19 and 315/30R19?

315/30R19 is 0.41" taller and 60 mm wider; the sidewall is +0.21". At an indicated 60 mph you'd actually be doing 61.0 mph.

Will 315/30R19 fit on 255/35R19 wheels?

Both use a 19" rim, so the wheel diameter matches; check the wheel's width range for a 315 mm tire and the fender clearance.