Section Width125 mm (4.9")
Aspect Ratio78%
Rim Diameter20"
Overall Diameter703 mm (27.7")
Sidewall Height98 mm
Circumference2209 mm
125/78R20 — Buy Tires

Everything to know about the 125/78R20 tire size

Size geometry

A 125/78R20 tire has a 125mm section width and a 78% aspect ratio, mounted on a 20-inch rim. Sidewall height works out to 97.5mm (3.84") and overall outside diameter is 703.0mm (27.68"). At highway speed the tire completes about 453 revolutions per kilometre — your speedometer and odometer were calibrated against this number.

Direct substitute sizes

If 125/78R20 is unavailable, the closest same-diameter substitutes on the same rim are 115/85R20 and 135/72R20. Both keep your speedometer reading within 1% — safe for daily use, ABS, and stability control. Always verify load and speed ratings before swapping.

Plus / minus sizing options

For a 125/78R20 you can upsize to 135/63R21 (plus-one) to fit a larger wheel without changing the speedometer reading, or downsize to 115/96R19 (minus-one) for a softer ride or winter setup. Both stay inside the Âą3% diameter tolerance that ABS and TPMS systems expect.

Vehicle compatibility

0 vehicles in our database run the 125/78R20 tire size from the factory. Aftermarket fitment depends on rim width, offset, and clearance — match these specs to your wheel before purchasing tires.

Vehicles Using 125/78R20

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