Section Width205 mm (8.1")
Aspect Ratio42%
Rim Diameter18"
Overall Diameter629 mm (24.8")
Sidewall Height86 mm
Circumference1977 mm
205/42R18 — Buy Tires

Everything to know about the 205/42R18 tire size

Size geometry

A 205/42R18 tire has a 205mm section width and a 42% aspect ratio, mounted on a 18-inch rim. Sidewall height works out to 86.1mm (3.39") and overall outside diameter is 629.4mm (24.78"). At highway speed the tire completes about 506 revolutions per kilometre — your speedometer and odometer were calibrated against this number.

Direct substitute sizes

If 205/42R18 is unavailable, the closest same-diameter substitutes on the same rim are 195/44R18 and 215/40R18. 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 205/42R18 you can upsize to 215/34R19 (plus-one) to fit a larger wheel without changing the speedometer reading, or downsize to 195/51R17 (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 205/42R18 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 205/42R18

tire_size.no_vehicles_found