In case your tyre has lost all or most of its pressure you should stop your car immediately and fit your spare tyre. Therefore FULDA suggests to regularly check the tyre pressure of your spare tyre as well so to make sure you can use it when you need it. Never continue driving on a flat tyre as this will damage the tyre structure. Once you have mounted your spare tyre you should visit a specialised tyre fitter to have your damaged tyre checked whether it can be repaired. Note that only a specialist tyre dealer can tell you if your tyre can be repaired, as the tyre must be removed from the wheel for a complete internal inspection to be sure it's not damaged. Flat tyres that are run even for short distances are often damaged beyond repair.

Most punctures, nail holes, or cuts up to 6mm in the tyre tread can be repaired by trained personnel using industry-approved methods. Tyres with tread punctures larger than 6mm, or any sidewall puncture should not be repaired. It is also recommended not to repair ultra high performance tyres (tyres with a speed rate W, Y or ZR). 

Please bear in mind that the final decision whether a tyre can be repaired or not should only be taken by trained tyre specialist.