CarSpecsHQ

245/40R19 vs 245/35R20

245/35R20 is a safe swap for 245/40R19 by the usual ±3% rule: the diameter differs by +0.13%.

19" → 20"
245/40R19 26.72" · 245/35R20 26.75" · drawn to scale

Side by side

245/40R19245/35R20Difference
Overall diameter26.72"26.75"+0.04" (+0.13%)
Section width245 mm245 mm0 mm
Sidewall3.86"3.38"-0.48"
Rim19"20"+1"
Circumference83.9"84.0"+0.1"
Revs per mile755754-1
Ride height——+0.02"
Speedometer reads 60 mph60.060.1+0.1 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.1 mph

With 245/35R20 on a car calibrated for 245/40R19, the speedometer reads 59.9 mph when you're really doing 60, and the odometer under-counts by 0.1%.

Speedo showsActual speed
30 mph30.0 mph
45 mph45.1 mph
60 mph60.1 mph
70 mph70.1 mph
80 mph80.1 mph

Other sizes close to 245/40R19

Questions

Can I replace 245/40R19 with 245/35R20?

245/35R20 is a safe swap for 245/40R19 by the usual ±3% rule: the diameter differs by +0.13%.

What's the difference between 245/40R19 and 245/35R20?

245/35R20 is 0.04" taller and 0 mm wider; the sidewall is -0.48". At an indicated 60 mph you'd actually be doing 60.1 mph.

Will 245/35R20 fit on 245/40R19 wheels?

No — 245/40R19 needs a 19" wheel and 245/35R20 a 20" wheel. This is a plus/minus-size swap that changes wheels too.