Section Width635 mm (25.0")
Aspect Ratio27%
Rim Diameter20"
Overall Diameter851 mm (33.5")
Sidewall Height171 mm
Circumference2673 mm
635/27R20 — Buy Tires

Everything to know about the 635/27R20 tire size

Size geometry

A 635/27R20 tire has a 635mm section width and a 27% aspect ratio, mounted on a 20-inch rim. Sidewall height works out to 171.4mm (6.75") and overall outside diameter is 850.9mm (33.50"). At highway speed the tire completes about 374 revolutions per kilometre — your speedometer and odometer were calibrated against this number.

Direct substitute sizes

If 635/27R20 is unavailable, the closest same-diameter substitutes on the same rim are 625/27R20 and 645/27R20. 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 635/27R20 you can upsize to 645/25R21 (plus-one) to fit a larger wheel without changing the speedometer reading, or downsize to 625/29R19 (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 635/27R20 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 635/27R20

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