Section Width685 mm (27.0")
Aspect Ratio29%
Rim Diameter18"
Overall Diameter855 mm (33.6")
Sidewall Height199 mm
Circumference2684 mm
685/29R18 — Buy Tires

Everything to know about the 685/29R18 tire size

Size geometry

A 685/29R18 tire has a 685mm section width and a 29% aspect ratio, mounted on a 18-inch rim. Sidewall height works out to 198.7mm (7.82") and overall outside diameter is 854.5mm (33.64"). At highway speed the tire completes about 373 revolutions per kilometre — your speedometer and odometer were calibrated against this number.

Direct substitute sizes

If 685/29R18 is unavailable, the closest same-diameter substitutes on the same rim are 675/29R18 and 695/29R18. 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 685/29R18 you can upsize to 695/27R19 (plus-one) to fit a larger wheel without changing the speedometer reading, or downsize to 675/31R17 (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 685/29R18 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 685/29R18

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