i had thought every driver, especially male ones, would know how to replace a puntured tyre until i came upon this young man struggling in vain to remove the wheel nuts holding the 'injured' tyre. seeing that he needed help, i asked if he had a jack. he did but he was not sure where to place it. he asked if he could place it on the exhaust pipe. i told him he had to find somewhere where the metal was re-inforced, somewhere strong enough. in every car, in the undercarriage there are lift points, strong enough for the jack to hold the car up.
he finally got the car jacked up. as he started to work on loosening the nuts, i realised that he was not applying the principle of mechanics to remove the nuts. the angle was wrong and he was not using his body weight to work on the unyielding nuts. he had positioned the wheel nut wrench at too acute an angle and although he was using all his strength, it would not budge. it would seem to me that those nuts had never been loosened since the day they were put in place.
i helped reposition the wrench at a less acute angle and showed him how to use the body weight to advantage. i have often watched car mechanics doing it - stepping on the handle with their foot. using this method, he managed to loosened all the nuts. then, it started to rain and i left him to fend for himself.
after this, he would have to jack up the car a bit more so that the affected wheel was not in contact with the ground. this way, he could dislodge the wheel with the punctured tyre and replaced it with the spare tyre.
in the past, most cars came equipped with a four-way wrench called a spider. today, most cars come with a simple l-shaped wrench.
