Tire Size & Ratings — FAQ
A plain-language guide to reading tire sizes, load index, speed ratings and more — for Canadian drivers, the way we explain it in the shop.
How do I know what tire size my vehicle needs?+
Your vehicle's recommended tire size is listed on the driver-side door placard and in the owner's manual. These specifications are set by the vehicle manufacturer and comply with Transport Canada and CMVSS.
Using the correct size ensures proper handling, braking, load capacity, and speed capability.
Can I read my tire size directly from the tire?+
Yes. Every tire has its size molded into the sidewall, e.g. 225/65R17 102H. This combination of numbers and letters tells you everything about how the tire is built and what it's designed to handle.
What do the numbers and letters on a tire mean?+
- Tire width — first number (e.g. 225), in millimetres
- Aspect ratio — second number (e.g. 65), sidewall height as a % of width
- R — radial construction
- Wheel diameter — next number (e.g. 17), in inches
- Load index — (e.g. 102) max weight the tire can carry
- Speed rating — final letter (e.g. H), tested max speed
What does “LT” mean on a tire?+
LT stands for Light Truck. LT tires handle heavier loads and tougher conditions — higher load capacity, stronger sidewalls and Load Range designations (e.g. Load Range E). Common on pickups, vans and work vehicles.
What is load index and why does it matter?+
The load index tells you how much weight each tire can safely carry. Exceeding it can affect safety and braking, vehicle compliance with CMVSS, and insurance coverage in an accident.
What does “XL” mean on a tire?+
XL means Extra Load — designed to carry more weight at higher inflation pressures. Example — Standard: 215/55R17 94V · Extra Load: 215/55R17 98V XL.
Do speed ratings matter in Canada?+
Yes. Replacement tires should meet or exceed the original equipment speed rating; if different ratings are installed, the lowest applies. Always obey posted speed limits — speed ratings are not recommended driving speeds.
Are winter tires different in Canada?+
Yes — many carry the Three-Peak Mountain Snowflake (3PMSF) symbol, indicating certified winter performance. Dedicated winter tires are not required to display UTQG ratings.
Can I change tire size from what's on my vehicle?+
Sometimes — but always with professional guidance. Changing size can affect load capacity, speed rating, wheel fitment and suspension/steering geometry. Talk to a qualified tire professional first.
Still unsure which tire is right for you?
Our team can confirm proper sizing, load ratings and winter requirements so your vehicle stays safe, compliant and performing as intended.