The stock tire size for the Honda Civic Si in the latest generations is 235/40R18 on 18-inch wheels.
Tire sizing for the Civic Si has varied by generation and market. This article explains the current standard and how it has evolved across recent model years, so buyers and owners know what to expect when replacing tires or fitting new wheels.
Current tire size for the Honda Civic Si
Below are the stock specifications for the two most recent, US-market generations. Always verify on your vehicle’s door-jamb placard or owner's manual, since wheel options can alter the exact sizing.
- 10th generation Civic Si (2017–2021): 235/40R18 on 18×8-inch wheels.
- 11th generation Civic Si (2022–present): 235/40R18 on 18×8-inch wheels.
In both generations, Honda has maintained the 235/40R18 sizing to balance grip and ride quality, with the option for different performance tire compounds depending on the trim and package.
Notes for owners and shoppers
If you’re replacing tires or considering aftermarket wheels, check the tire placard on the driver’s door jamb for the exact specification for your VIN. When shopping used cars or aftermarket packages, confirm that the size matches 235/40R18 on 18-inch rims and that the load and speed ratings meet or exceed the original spec.
Summary
The current stock tire size for Honda Civic Si models is 235/40R18 on 18-inch wheels. Always verify the exact spec for your vehicle, as regional options or wheel packages can alter the size.