235/40R18 Tire Size Specifications
This tire size 235/40R18 fits 14 vehicles in our database.
Everything to know about the 235/40R18 tire size
Size geometry
A 235/40R18 tire has a 235mm section width and a 40% aspect ratio, mounted on a 18-inch rim. Sidewall height works out to 94.0mm (3.70") and overall outside diameter is 645.2mm (25.40"). At highway speed the tire completes about 493 revolutions per kilometre â your speedometer and odometer were calibrated against this number.
Direct substitute sizes
If 235/40R18 is unavailable, the closest same-diameter substitutes on the same rim are 225/42R18 and 245/38R18. 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 235/40R18 you can upsize to 245/33R19 (plus-one) to fit a larger wheel without changing the speedometer reading, or downsize to 225/47R17 (minus-one) for a softer ride or winter setup. Both stay inside the Âą3% diameter tolerance that ABS and TPMS systems expect.
Vehicle compatibility
14 vehicles in our database run the 235/40R18 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 235/40R18
Acura Integra
Years: 2023 - 2026
Alfa Romeo 4C
Years: 2013 - 2020
Alpine A110
Years: 2017 - 2026
Audi R8
Years: 2006 - 2015
Audi S4
Years: 2003 - 2008
Elfin MS8 Streamliner
Years: 2004 - 2012
Ford Focus
Years: 2018 - 2026
Holden Monaro
Years: 2001 - 2006
Honda Civic
Years: 2016 - 2021
Mercedes-Benz A-Class
Years: 2014 - 2018
Mercedes-Benz CLA
Years: 2014 - 2019
Mercedes-Benz SLK
Years: 2016 - 2020
Toyota Corolla
Years: 2023 - 2026
Volkswagen Passat
Years: 2005 - 2010