Section Width645 mm (25.4")
Aspect Ratio66%
Rim Diameter10"
Overall Diameter1105 mm (43.5")
Sidewall Height426 mm
Circumference3473 mm
645/66R10 — Buy Tires

Everything to know about the 645/66R10 tire size

Size geometry

A 645/66R10 tire has a 645mm section width and a 66% aspect ratio, mounted on a 10-inch rim. Sidewall height works out to 425.7mm (16.76") and overall outside diameter is 1105.4mm (43.52"). At highway speed the tire completes about 288 revolutions per kilometre — your speedometer and odometer were calibrated against this number.

Direct substitute sizes

If 645/66R10 is unavailable, the closest same-diameter substitutes on the same rim are 635/67R10 and 655/65R10. 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 645/66R10 you can upsize to 655/63R11 (plus-one) to fit a larger wheel without changing the speedometer reading, or downsize to 635/69R9 (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 645/66R10 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 645/66R10

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