CarSpecsHQ

235/50R19 vs 265/40R20

265/40R20 is a safe swap for 235/50R19 by the usual ±3% rule: the diameter differs by +0.33%.

19" → 20"
235/50R19 28.25" · 265/40R20 28.35" · drawn to scale

Side by side

235/50R19265/40R20Difference
Overall diameter28.25"28.35"+0.09" (+0.33%)
Section width235 mm265 mm+30 mm
Sidewall4.63"4.17"-0.45"
Rim19"20"+1"
Circumference88.8"89.1"+0.3"
Revs per mile714711-2
Ride height——+0.05"
Speedometer reads 60 mph60.060.2+0.2 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.2 mph

With 265/40R20 on a car calibrated for 235/50R19, the speedometer reads 59.8 mph when you're really doing 60, and the odometer under-counts by 0.3%.

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

Other sizes close to 235/50R19

Questions

Can I replace 235/50R19 with 265/40R20?

265/40R20 is a safe swap for 235/50R19 by the usual ±3% rule: the diameter differs by +0.33%.

What's the difference between 235/50R19 and 265/40R20?

265/40R20 is 0.09" taller and 30 mm wider; the sidewall is -0.45". At an indicated 60 mph you'd actually be doing 60.2 mph.

Will 265/40R20 fit on 235/50R19 wheels?

No — 235/50R19 needs a 19" wheel and 265/40R20 a 20" wheel. This is a plus/minus-size swap that changes wheels too.