Section Width155 mm (6.1")
Aspect Ratio178%
Rim Diameter18"
Overall Diameter1009 mm (39.7")
Sidewall Height276 mm
Circumference3170 mm
155/178R18 — Buy Tires

Everything to know about the 155/178R18 tire size

Size geometry

A 155/178R18 tire has a 155mm section width and a 178% aspect ratio, mounted on a 18-inch rim. Sidewall height works out to 275.9mm (10.86") and overall outside diameter is 1009.0mm (39.72"). At highway speed the tire completes about 315 revolutions per kilometre — your speedometer and odometer were calibrated against this number.

Direct substitute sizes

If 155/178R18 is unavailable, the closest same-diameter substitutes on the same rim are 145/190R18 and 165/167R18. 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 155/178R18 you can upsize to 165/160R19 (plus-one) to fit a larger wheel without changing the speedometer reading, or downsize to 145/199R17 (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 155/178R18 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 155/178R18

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