Section Width505 mm (19.9")
Aspect Ratio20%
Rim Diameter21"
Overall Diameter735 mm (28.9")
Sidewall Height101 mm
Circumference2310 mm
505/20R21 — Buy Tires

Everything to know about the 505/20R21 tire size

Size geometry

A 505/20R21 tire has a 505mm section width and a 20% aspect ratio, mounted on a 21-inch rim. Sidewall height works out to 101.0mm (3.98") and overall outside diameter is 735.4mm (28.95"). At highway speed the tire completes about 433 revolutions per kilometre — your speedometer and odometer were calibrated against this number.

Direct substitute sizes

If 505/20R21 is unavailable, the closest same-diameter substitutes on the same rim are 495/20R21 and 515/20R21. 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 505/20R21 you can upsize to 515/17R22 (plus-one) to fit a larger wheel without changing the speedometer reading, or downsize to 495/23R20 (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 505/20R21 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 505/20R21

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