Check the tyre size on your current rear tyres, then confirm against the vehicle handbook and the tyre information sticker on the door pillar or fuel flap. This size is commonly part of a staggered set-up, so verify the front and rear sizes separately before you order.
Match the load index and speed rating shown on your existing tyre sidewall or specified by the manufacturer, and do not go below it. For performance SUVs, 315/35 R21 is often supplied with higher ratings (for example, a Y speed rating and an XL marking), so use the exact specification listed for your car when comparing options.
If your car was originally supplied with runflats, it is usually best to stick with runflat tyres unless your manufacturer or fitter confirms a suitable switch. If runflats are not required, many drivers choose an XL version in 315/35 R21 to better support the higher loads typically carried by this wide rear fitment.
It is normally recommended to replace tyres in pairs on the same axle to keep handling and grip consistent, especially with wide rear tyres like 315/35 R21. If you are replacing a single tyre due to damage, ask your fitter to check tread depth differences and confirm it will not affect stability or traction systems.
Yes, but the choice can be more limited than summer performance options because this size is often fitted to high-powered vehicles. When selecting an all-season or winter tyre in 315/35 R21, prioritise the correct load and speed rating for your car and look for the 3PMSF marking if you need genuine winter certification.
