CarSpecsHQ

275/35R20 vs 245/45R19

245/45R19 is a safe swap for 275/35R20 by the usual ±3% rule: the diameter differs by +0.37%.

20" → 19"
275/35R20 27.58" · 245/45R19 27.68" · drawn to scale

Side by side

275/35R20245/45R19Difference
Overall diameter27.58"27.68"+0.10" (+0.37%)
Section width275 mm245 mm-30 mm
Sidewall3.79"4.34"+0.55"
Rim20"19"-1"
Circumference86.6"87.0"+0.3"
Revs per mile731729-3
Ride height——+0.05"
Speedometer reads 60 mph60.060.2+0.2 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.2 mph

With 245/45R19 on a car calibrated for 275/35R20, the speedometer reads 59.8 mph when you're really doing 60, and the odometer under-counts by 0.4%.

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

Other sizes close to 275/35R20

Questions

Can I replace 275/35R20 with 245/45R19?

245/45R19 is a safe swap for 275/35R20 by the usual ±3% rule: the diameter differs by +0.37%.

What's the difference between 275/35R20 and 245/45R19?

245/45R19 is 0.10" taller and 30 mm narrower; the sidewall is +0.55". At an indicated 60 mph you'd actually be doing 60.2 mph.

Will 245/45R19 fit on 275/35R20 wheels?

No — 275/35R20 needs a 20" wheel and 245/45R19 a 19" wheel. This is a plus/minus-size swap that changes wheels too.