It describes the tyre’s dimensions and construction. 235 is the width in millimetres, 45 is the profile (sidewall height as a percentage of the width), R means radial construction, and 17 is the wheel diameter in inches. When buying, also match the load index and speed rating printed after the size.
Choose the load version specified for your car, which you can confirm on the existing sidewall, the door jamb sticker, or the handbook. If your current tyres are XL (extra load), replace like-for-like to maintain the required load capacity. If they are standard load, do not drop to a lower load index, and only move to XL if the load index and pressures remain suitable for the vehicle.
Often yes, but it depends on the vehicle setup and what you carry for punctures. If your car was supplied with runflats and has no spare wheel, you will usually need a puncture repair kit or space saver solution before switching. Avoid mixing runflat and non-runflat tyres on the same axle, and consider changing in pairs to keep handling consistent.
Summer tyres suit most UK driving when temperatures are generally above 7°C and you want the best steering response and braking in warm, wet conditions. Winter tyres are the right pick if you regularly face icy roads or travel in colder regions where temperatures stay low. All-season tyres offer a practical middle ground for mixed weather, especially if you want one set year-round without seasonal swaps.
Match or exceed the speed rating recommended by the manufacturer, and keep it consistent across each axle. Common ratings in this size include V, W and Y depending on the car’s performance level. If you are unsure, use the rating shown on your current tyre sidewall as a starting point and confirm against the vehicle placard or handbook before ordering.
