CarSpecsHQ

265/45R20 vs 245/50R20

245/50R20 is a safe swap for 265/45R20 by the usual ±3% rule: the diameter differs by +0.87%.

20" rim
265/45R20 29.39" · 245/50R20 29.65" · drawn to scale

Side by side

265/45R20245/50R20Difference
Overall diameter29.39"29.65"+0.26" (+0.87%)
Section width265 mm245 mm-20 mm
Sidewall4.69"4.82"+0.13"
Rim20"20"same
Circumference92.3"93.1"+0.8"
Revs per mile686680-6
Ride height——+0.13"
Speedometer reads 60 mph60.060.5+0.5 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.5 mph

With 245/50R20 on a car calibrated for 265/45R20, the speedometer reads 59.5 mph when you're really doing 60, and the odometer under-counts by 0.9%.

Speedo showsActual speed
30 mph30.3 mph
45 mph45.4 mph
60 mph60.5 mph
70 mph70.6 mph
80 mph80.7 mph

Other sizes close to 265/45R20

Questions

Can I replace 265/45R20 with 245/50R20?

245/50R20 is a safe swap for 265/45R20 by the usual ±3% rule: the diameter differs by +0.87%.

What's the difference between 265/45R20 and 245/50R20?

245/50R20 is 0.26" taller and 20 mm narrower; the sidewall is +0.13". At an indicated 60 mph you'd actually be doing 60.5 mph.

Will 245/50R20 fit on 265/45R20 wheels?

Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 245 mm tire and the fender clearance.