CarSpecsHQ

225/35R20 vs 315/30R19

315/30R19 is a safe swap for 225/35R20 by the usual ±3% rule: the diameter differs by +0.92%.

20" → 19"
225/35R20 26.20" · 315/30R19 26.44" · drawn to scale

Side by side

225/35R20315/30R19Difference
Overall diameter26.20"26.44"+0.24" (+0.92%)
Section width225 mm315 mm+90 mm
Sidewall3.10"3.72"+0.62"
Rim20"19"-1"
Circumference82.3"83.1"+0.8"
Revs per mile770763-7
Ride height——+0.12"
Speedometer reads 60 mph60.060.5+0.5 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.5 mph

With 315/30R19 on a car calibrated for 225/35R20, the speedometer reads 59.5 mph when you're really doing 60, and the odometer under-counts by 0.9%.

Speedo showsActual speed
30 mph30.3 mph
45 mph45.4 mph
60 mph60.5 mph
70 mph70.6 mph
80 mph80.7 mph

Other sizes close to 225/35R20

Questions

Can I replace 225/35R20 with 315/30R19?

315/30R19 is a safe swap for 225/35R20 by the usual ±3% rule: the diameter differs by +0.92%.

What's the difference between 225/35R20 and 315/30R19?

315/30R19 is 0.24" taller and 90 mm wider; the sidewall is +0.62". At an indicated 60 mph you'd actually be doing 60.5 mph.

Will 315/30R19 fit on 225/35R20 wheels?

No — 225/35R20 needs a 20" wheel and 315/30R19 a 19" wheel. This is a plus/minus-size swap that changes wheels too.