CarSpecsHQ

225/35R20 vs 305/30R19

305/30R19 is a safe swap for 225/35R20 by the usual ±3% rule: the diameter differs by +0.02%.

20" → 19"
225/35R20 26.20" · 305/30R19 26.20" · drawn to scale

Side by side

225/35R20305/30R19Difference
Overall diameter26.20"26.20"+0.00" (+0.02%)
Section width225 mm305 mm+80 mm
Sidewall3.10"3.60"+0.50"
Rim20"19"-1"
Circumference82.3"82.3"+0.0"
Revs per mile770770-0
Ride height——+0.00"
Speedometer reads 60 mph60.060.0+0.0 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.0 mph

With 305/30R19 on a car calibrated for 225/35R20, the speedometer reads 60.0 mph when you're really doing 60, and the odometer under-counts by 0.0%.

Speedo showsActual speed
30 mph30.0 mph
45 mph45.0 mph
60 mph60.0 mph
70 mph70.0 mph
80 mph80.0 mph

Other sizes close to 225/35R20

Questions

Can I replace 225/35R20 with 305/30R19?

305/30R19 is a safe swap for 225/35R20 by the usual ±3% rule: the diameter differs by +0.02%.

What's the difference between 225/35R20 and 305/30R19?

305/30R19 is 0.00" taller and 80 mm wider; the sidewall is +0.50". At an indicated 60 mph you'd actually be doing 60.0 mph.

Will 305/30R19 fit on 225/35R20 wheels?

No — 225/35R20 needs a 20" wheel and 305/30R19 a 19" wheel. This is a plus/minus-size swap that changes wheels too.