CarSpecsHQ

225/40R18 vs 225/35R19

225/35R19 is a safe swap for 225/40R18 by the usual ±3% rule: the diameter differs by +0.46%.

18" → 19"
225/40R18 25.09" · 225/35R19 25.20" · drawn to scale

Side by side

225/40R18225/35R19Difference
Overall diameter25.09"25.20"+0.11" (+0.46%)
Section width225 mm225 mm0 mm
Sidewall3.54"3.10"-0.44"
Rim18"19"+1"
Circumference78.8"79.2"+0.4"
Revs per mile804800-4
Ride height——+0.06"
Speedometer reads 60 mph60.060.3+0.3 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.3 mph

With 225/35R19 on a car calibrated for 225/40R18, the speedometer reads 59.7 mph when you're really doing 60, and the odometer under-counts by 0.5%.

Speedo showsActual speed
30 mph30.1 mph
45 mph45.2 mph
60 mph60.3 mph
70 mph70.3 mph
80 mph80.4 mph

Other sizes close to 225/40R18

Questions

Can I replace 225/40R18 with 225/35R19?

225/35R19 is a safe swap for 225/40R18 by the usual ±3% rule: the diameter differs by +0.46%.

What's the difference between 225/40R18 and 225/35R19?

225/35R19 is 0.11" taller and 0 mm wider; the sidewall is -0.44". At an indicated 60 mph you'd actually be doing 60.3 mph.

Will 225/35R19 fit on 225/40R18 wheels?

No — 225/40R18 needs a 18" wheel and 225/35R19 a 19" wheel. This is a plus/minus-size swap that changes wheels too.