f you're a member of one of the many roadside assistance plans you'll know that changing a flat tyre is something they do on call. But what happens if your cellphone is out of range, or your cellphone battery is flat, or heaven forbid, you're on a long, deserted road in the middle of nowhere. You don't want to stand around waiting.
OK, so you are driving along and all of the sudden you hear a loud bang and the telltale thumping noise of a dead tire. You carefully pull off to the shoulder of the road. Checking to make sure no other motorists are going to run you over, you exit your vehicle and inspect the car. Sure enough, your car's left front tyre is completely flat. You are not going to be able to keep driving, so you are going to have to remove it and install your spare tyre in its place.
Jack up the Car
The first step is to pull out the spare tyre, jack and tyre iron. The spare tire is almost always located underneath the floor mat in the boot. Unless, of course, your car doesn't have a boot. If you own an SUV, minivan or pickup, the spare tyre is often mounted on the back of the tailgate or underneath the back of vehicle itself.
The next step will involve removing the flat tyre. Make sure that the car is in gear (or in "park" if the car is an automatic) and the emergency brake is set. The car should be parked on a flat piece of road. Do not attempt to change a flat if the car is on a slope or if it is sitting on dirt. It's also a good idea to block the tyre opposite of the flat tyre. Therefore, if the left front tyre is flat, it would be a good idea to place a brick or other large, heavy object behind the right rear tyre. Blocking the tyre makes the car less likely to move when you are raising it.
Use the tire iron (the L-shaped bar that fits over the wheel lugs) to loosen each wheel lug. The wheel lugs are almost certainly very tight. You'll have to use brute force. You loosen them by turning them counterclockwise, by the way. You don't want to actually remove the lugs - only to loosen them. Once you have accomplished this, move the jack underneath the car. If you don't know where the proper jacking points are, look them up in the owner's manual (you keep your owner's manual in your car, right?).
Maneuver the jack underneath the jack point and start to raise the jack. Most car jacks these days are a screw-type scissor jack, which means you simply turn the knob at the end of the jack using the provided metal hand crank. Raise the jack until it contacts the frame of the car and continue expanding the jack.
Remove the flat and install the spare
Raise the car with the jack until the flat tyre is completely raised off the ground. Once this is done, remove the wheel lugs completely. Depending on how tight the lugs are you might be able to remove them by hand. Set the lugs aside in a secure location where they can't roll away.
Position the spare tire over the wheel studs. This is the most physically challenging part of the whole process. You'll have to hold up the tyre and try to line up the holes in the wheel with the protruding wheel studs located on the brake hub. One trick that might help is to balance the tyre on your foot while you move it into position.
After you have the spare tire hanging on the wheel studs, screw each of the wheel lugs back on. You'll want to start them by hand. The lugs should screw on easily. Once each of them is snug and you can't tighten them any further by hand, use the tyre iron to finish the job. At this point, you don't need to get the lugs super tight. You just want them snug for now. Make sure that the wheel is fitting flush against the brake hub.
Once the spare tyre is on, carefully lower the jack. Pull the jack away from the vehicle. The final step is to tighten down the lugs completely. The reason you tighten the lugs now is that the tyre is on the ground and it won't rotate around like it would if it was still hanging in the air.
Wheel lugs have a specific torque rating that they are supposed to be tightened down to, but there is pretty much no way you can figure that out using a simple tyre iron. The general rule here is to tighten down the lugs as much as possible.