305/70R18 Tire Size Specifications
This tire size 305/70R18 fits 1 vehicles in our database.
Everything to know about the 305/70R18 tire size
Size geometry
A 305/70R18 tire has a 305mm section width and a 70% aspect ratio, mounted on a 18-inch rim. Sidewall height works out to 213.5mm (8.41") and overall outside diameter is 884.2mm (34.81"). At highway speed the tire completes about 360 revolutions per kilometre â your speedometer and odometer were calibrated against this number.
Direct substitute sizes
If 305/70R18 is unavailable, the closest same-diameter substitutes on the same rim are 295/72R18 and 315/68R18. 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 305/70R18 you can upsize to 315/64R19 (plus-one) to fit a larger wheel without changing the speedometer reading, or downsize to 295/77R17 (minus-one) for a softer ride or winter setup. Both stay inside the Âą3% diameter tolerance that ABS and TPMS systems expect.
Vehicle compatibility
1 vehicles in our database run the 305/70R18 tire size from the factory. Aftermarket fitment depends on rim width, offset, and clearance â match these specs to your wheel before purchasing tires.