Check the tyre sidewall on your current set, then match it against the vehicle handbook or the tyre label (often on the driver door shut or fuel flap). If your car lists multiple approved sizes, stick to an approved option and make sure the load index and speed rating also meet or exceed the manufacturer requirement.
Choose the exact specification shown on your existing tyres or in your vehicle documentation. Common fitments include ratings such as 94W and higher-spec options like 98Y XL, but the correct choice depends on your car, trim and axle load. Do not select a lower load index or speed rating than recommended, as it can affect safety, insurance and MOT compliance.
XL (extra load) versions have a higher load capacity and a stiffer construction, which can suit heavier trims, frequent motorway use or cars that specify XL from the factory. If your vehicle placard or handbook calls for XL, match it like-for-like. If it does not, standard load tyres can deliver a more compliant ride, so use the manufacturer spec as your deciding factor.
Run-flat options are available in 225/50 R17 from several manufacturers. Only choose them if your vehicle is designed for run-flats (or you have an appropriate spare or mobility kit and your insurer is happy with the change). Avoid mixing run-flat and non run-flat tyres on the same axle, as it can create inconsistent handling and braking feel.
Fitting a pair on the same axle is usually the better option because it keeps grip and braking balanced left to right. If you replace just one, check the remaining tyre has even wear and similar tread depth, as large differences can affect stability and traction control behaviour. As part of the replacement, it is also worth checking wheel alignment to help the new tyre wear evenly.
