CarSpecsHQ

265/35R20 vs 245/45R20

245/45R20 is outside the ±3% rule as a replacement for 265/35R20: the diameter differs by +5.05%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

20" rim
265/35R20 27.30" · 245/45R20 28.68" · drawn to scale

Side by side

265/35R20245/45R20Difference
Overall diameter27.30"28.68"+1.38" (+5.05%)
Section width265 mm245 mm-20 mm
Sidewall3.65"4.34"+0.69"
Rim20"20"same
Circumference85.8"90.1"+4.3"
Revs per mile739703-35
Ride height——+0.69"
Speedometer reads 60 mph60.063.0+3.0 mph

Speedometer and odometer

020406080100120 reads 60 · actual 63.0 mph

With 245/45R20 on a car calibrated for 265/35R20, the speedometer reads 57.1 mph when you're really doing 60, and the odometer under-counts by 5.0%.

Speedo showsActual speed
30 mph31.5 mph
45 mph47.3 mph
60 mph63.0 mph
70 mph73.5 mph
80 mph84.0 mph

Other sizes close to 265/35R20

Questions

Can I replace 265/35R20 with 245/45R20?

245/45R20 is outside the ±3% rule as a replacement for 265/35R20: the diameter differs by +5.05%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

What's the difference between 265/35R20 and 245/45R20?

245/45R20 is 1.38" taller and 20 mm narrower; the sidewall is +0.69". At an indicated 60 mph you'd actually be doing 63.0 mph.

Will 245/45R20 fit on 265/35R20 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.