685/30R18 Tire Size Specifications
This tire size 685/30R18 fits 0 vehicles in our database.
Everything to know about the 685/30R18 tire size
Size geometry
A 685/30R18 tire has a 685mm section width and a 30% aspect ratio, mounted on a 18-inch rim. Sidewall height works out to 205.5mm (8.09") and overall outside diameter is 868.2mm (34.18"). At highway speed the tire completes about 367 revolutions per kilometre â your speedometer and odometer were calibrated against this number.
Direct substitute sizes
If 685/30R18 is unavailable, the closest same-diameter substitutes on the same rim are 675/30R18 and 695/30R18. Both keep your speedometer reading within 1% â safe for daily use, ABS, and stability control. Always verify load and speed ratings before swapping.
Plus / minus sizing options
For a 685/30R18 you can upsize to 695/28R19 (plus-one) to fit a larger wheel without changing the speedometer reading, or downsize to 675/32R17 (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 685/30R18 tire size from the factory. Aftermarket fitment depends on rim width, offset, and clearance â match these specs to your wheel before purchasing tires.
Vehicles Using 685/30R18
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