It can be either, so check the tyre markings. A temporary space-saver is often marked with a T at the start (for example, T135/80 R15) and may also show usage limits such as a maximum speed. A standard 135/80 R15 road tyre will not have the T prefix and is designed for normal driving when it matches your vehicle specification.
Match what your car was supplied with. Look in the handbook, on the tyre label (usually inside the driver door area), or on the spare wheel itself. If the original spare is labelled T135/80 R15, buy the same type and follow the temporary-use guidance. If your car specifies a standard 135/80 R15 for regular fitment, choose a normal road tyre with the correct load index and speed rating.
Only if the vehicle manufacturer approves it. Changing width or profile alters overall diameter and clearance, which can affect speedometer accuracy, handling balance and the way the tyre fits the wheel arch. For the safest like-for-like replacement, stick to 135/80 R15 unless your handbook or a trusted fitment guide confirms an alternative is permitted for your specific model and wheel.
Use the ratings shown on your current tyre sidewall or your vehicle placard as the minimum. With this narrow size, load and speed ratings can vary between products, so filter options to match your required specification before buying. If it is for a space-saver application, follow the vehicle and tyre guidance for any speed or distance restrictions.
For regular driving tyres, replacing in pairs on the same axle is usually the best approach because it keeps grip and braking behaviour consistent left to right. If only one tyre is being replaced, ensure the remaining tyre has safe tread depth and similar wear, and keep the newest pair on the rear axle unless your vehicle manufacturer states otherwise. If you are replacing a compact spare, a single replacement is normally fine as long as it matches the original specification.
