Check the tyre size on your current sidewall and confirm it matches your vehicle placard (usually in the driver door shut or fuel flap) or your handbook. Make sure the load index and speed rating also meet or exceed the manufacturer specification, as this size is often used on sportier trims with higher rating requirements.
The 45 profile has a taller sidewall than the 40 profile, which changes overall rolling diameter and can affect speedometer accuracy, gearing feel and arch clearance. Unless your vehicle is approved for both sizes, stick with the size listed on the placard and keep the same size across an axle to avoid handling and stability issues.
Many cars that use this size specify XL because the tyre needs to support higher loads at the pressures recommended for sporty suspension setups. If your current tyres are marked XL or your placard lists a load index that typically comes in XL, choose an XL option and match the load index exactly or higher.
If you regularly drive in cold, wet conditions or encounter slush and occasional snow, all-season can be a strong year-round choice. For frequent winter driving or rural routes, a dedicated winter tyre in this size will usually give better cold-weather grip and braking, while summer tyres remain best for warm-weather performance.
The 40 profile sidewall is relatively short, so there is less tyre flex to cushion sharp impacts. Keeping pressures set to the vehicle placard and choosing a quality tyre construction can help, and it is worth checking wheel alignment if you notice vibrations, uneven wear or pulling after hitting potholes.
