265/45R20 vs 245/55R19

Q: Can I replace 265/45R20 with 245/55R19?

245/55R19 is a safe swap for 265/45R20 by the usual ±3% rule: the diameter differs by +0.75%.

245/55R19 is a safe swap for 265/45R20 by the usual ±3% rule: the diameter differs by +0.75%.

265/45R20 29.39" · 245/55R19 29.61" · drawn to scale

Side by side

	265/45R20	245/55R19	Difference
Overall diameter	29.39"	29.61"	+0.22" (+0.75%)
Section width	265 mm	245 mm	-20 mm
Sidewall	4.69"	5.31"	+0.61"
Rim	20"	19"	-1"
Circumference	92.3"	93.0"	+0.7"
Revs per mile	686	681	-5
Ride height	—	—	+0.11"
Speedometer reads 60 mph	60.0	60.5	+0.5 mph

Speedometer and odometer

With 245/55R19 on a car calibrated for 265/45R20, the speedometer reads 59.6 mph when you're really doing 60, and the odometer under-counts by 0.8%.

Speedo shows	Actual speed
30 mph	30.2 mph
45 mph	45.3 mph
60 mph	60.5 mph
70 mph	70.5 mph
80 mph	80.6 mph

Other sizes close to 265/45R20

Questions

Can I replace 265/45R20 with 245/55R19?

245/55R19 is a safe swap for 265/45R20 by the usual ±3% rule: the diameter differs by +0.75%.

What's the difference between 265/45R20 and 245/55R19?

245/55R19 is 0.22" taller and 20 mm narrower; the sidewall is +0.61". At an indicated 60 mph you'd actually be doing 60.5 mph.

Will 245/55R19 fit on 265/45R20 wheels?

No — 265/45R20 needs a 20" wheel and 245/55R19 a 19" wheel. This is a plus/minus-size swap that changes wheels too.