today I got a cut on my leg because of my father car. i help him to find the key to unscrew the tyres out, it sound a bit crazy why do you need a key to unscrew the tyres? , ok let me explain to you . you can unscrew all the four nuts but the last one must need a key to open the screw but unfourtnely we have lost that key so the machanic is unable to replace the brake pad. sigh. why do car have this kind of funtion call the "prevent rim from stolen" "qoute (from bmw)"