I’d like to know if it is dangerous to fit tyres which say 205/55/ 16h when it says inside my car door that I’m supposed to use 205/55/16v.
Every make of vehicle comes with tyres suitable and especially adapted to the axle, rim size, performance, breaking and weight of the said vehicle. There is a safety risk as well as a legal requirement. According to the law, you should respect the size, speed and load ratings recommended by the makers. You would fail your MOT/ safety and maintenance test. If it is a winter tyre, you can lower the speed index and go from V to H.