Section Width155 mm (6.1")
Aspect Ratio42%
Rim Diameter18"
Overall Diameter587 mm (23.1")
Sidewall Height65 mm
Circumference1845 mm
155/42R18 — Buy Tires

Everything to know about the 155/42R18 tire size

Size geometry

A 155/42R18 tire has a 155mm section width and a 42% aspect ratio, mounted on a 18-inch rim. Sidewall height works out to 65.1mm (2.56") and overall outside diameter is 587.4mm (23.13"). At highway speed the tire completes about 542 revolutions per kilometre — your speedometer and odometer were calibrated against this number.

Direct substitute sizes

If 155/42R18 is unavailable, the closest same-diameter substitutes on the same rim are 145/45R18 and 165/39R18. 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 155/42R18 you can upsize to 165/32R19 (plus-one) to fit a larger wheel without changing the speedometer reading, or downsize to 145/54R17 (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 155/42R18 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 155/42R18

tire_size.no_vehicles_found