225/40R18 Tires

What 225/40R18 means

The 225/40R18 marking is three measurements: 225 is the tread width in millimetres, 40 is the aspect ratio — the sidewall height as a percentage of that width — and 18″ is the wheel rim it mounts on.

The numbers for this size

These follow from the size itself: sidewall is 225 × 40%, and the overall diameter is the 18″ rim plus that sidewall twice over. The revolutions figure is what your speedometer is calibrated against — fit a size with a noticeably different diameter and the reading drifts.

How 225/40R18 drives

This is a low-profile fitment. The short sidewall means steering response is sharp and the car feels planted through corners, but there is less rubber to absorb impacts — on Ontario roads that makes pothole season harder on both the tyre and the rim.

What we stock in 225/40R18

We have 2 brand new tires in this size on the racks in Brampton, in these specifications:

• Tread pattern RUNSPIRIT, load and speed rating 92W
• Tread pattern HD625, load and speed rating 92Y

The load index and speed rating have to meet or beat what the sticker inside your driver door specifies — fitting below it is unsafe and can matter in an insurance claim. Our guide to load index and speed ratings explains how to read those codes.

Sizes close to 225/40R18

These are the other sizes we stock whose overall diameter sits within 3% of 225/40R18 — the accepted limit for an alternative fitment. Past that the speedometer reads wrong and, on some vehicles, the traction control starts behaving oddly. Always check against your door sticker before switching.

Fitting 225/40R18 in Brampton

Buy here and we mount, balance and torque the set while you wait — usually under an hour for four — at 80 Hale Rd, Unit 3, Brampton. Or order online and we deliver across the GTA, with the charge for your city shown in the cart before you pay. Not sure 225/40R18 is what your vehicle takes? Check the sticker inside the driver door, or read what tire size fits my car.

Frequently asked questions

What does 225/40R18 mean?

In 225/40R18, 225 is the tire width in millimetres, 40 is the aspect ratio (sidewall height as a percentage of width), and 18 is the wheel rim diameter in inches.

Where can I buy 225/40R18 tires near me?

Atika Auto Parts at 80 Hale Rd, Unit 3, Brampton stocks brand new 225/40R18 tires and fits them for drivers across Brampton, Mississauga, Caledon, Halton and Vaughan. Call +1 (204) 962-8513 to confirm stock.