A good jack can be the most useful tool you can have for changing a tire, whether on the side of the road or at home in your garage. Jacks are available in several different types, and all have their preferred uses. Scissor jacks are quite common and the type of jack most people have in their cars. They are simple in design and functionality. A small crank is connected to the scissor jack. When turned, it turns a large, threaded bar within the jack. That, in turn, moves the two ends of the jack closer together, pushing the arms upward. Scissor jacks are small and easy to stow, making them ideal for carrying in cars and small trucks. When closing, simply screw it the other way, the arms spread back apart, and the jack flattens out for storage. Floor jacks, though bulkier, are safe and easy to use, and large ones can lift several tons. Bottle jacks are compact and easy to store, are easily transportable, but frequently won’t lift as heavy of loads as a floor jack.