The basic tools that let you change a tire without calling for help
You need four things to change a tire: a jack to lift the car, a lug wrench to remove the wheel bolts, a spare tire, and a tire iron or socket wrench to break the bolts loose. Most cars come with a scissor jack and a lug wrench in the trunk or under the rear seat. If you have those two, you already own the hardest part to replace. A spare tire is usually mounted under the trunk floor or on the back of the vehicle. The tire iron is often built into the lug wrench as a cross-shaped tool, or it may be a separate flat bar.
You do not need expensive equipment or a full garage setup. The tools that come with your car will work for a roadside flat. However, understanding what each tool does and how to use it safely makes the difference between a 20-minute job and a frustrating hour in the dark.
Key Takeaways
- A scissor jack lifts the car, a lug wrench removes the bolts, and a tire iron breaks them loose — most cars include these in the trunk.
- A cross-shaped lug wrench is easier to use than a single-socket wrench because the longer arms give you more leverage to break tight bolts.
- A hydraulic floor jack is safer and faster than a scissor jack if you change tires at home, but a scissor jack is portable enough for the road.
- Wheel chocks or blocks behind the wheels prevent the car from rolling while you work, which is more important than many people realize.
- A torque wrench ensures you tighten bolts to the manufacturer's specification, which keeps the wheel find without damaging the studs.
The jack: how to lift the car safely
A scissor jack is the small, diamond-shaped jack that comes in most cars. It works by turning a handle that pushes a threaded rod upward, which spreads the diamond shape and lifts the car. Scissor jacks are lightweight and fit in a trunk, but they are slow and require you to crank the handle many times. They also sit low to the ground, so you need a flat, hard surface — they can sink into soft asphalt or dirt.
A hydraulic floor jack uses fluid pressure to lift the car much faster and with less effort. You pump a handle a few times and the car rises. Floor jacks are stronger and more stable than scissor jacks, but they are heavier and take up more space. If you change tires at home, a floor jack is worth the investment. If you are buying a jack for roadside use only, the scissor jack that came with your car will do the job.
Never work under a car supported only by a jack. Always place jack stands under the frame once the car is lifted. Jack stands are metal posts with a flat top that hold the weight while you work. A jack can fail or slip; jack stands are your safety backup. If you do not have jack stands, do not get under the car — just change the tire with the car lifted but do not crawl underneath.
The lug wrench: removing the wheel bolts
A lug wrench is a metal tool with sockets on each end designed to fit the bolts that hold the wheel on. The most common type is a cross-shaped wrench with four different socket sizes, one on each arm. This design is useful because you can try each size until one fits your bolts, and the long arms give you leverage to break tight bolts loose.
A single-socket lug wrench fits only one bolt size, so it is faster if you already know your size, but it gives you less leverage. Some people carry both — a cross wrench for breaking bolts loose and a single socket for the final tightening. The cross wrench is usually sufficient for a roadside change.
Before you lift the car, use the lug wrench to break the bolts loose while the wheel is still on the ground. This is important: the weight of the car keeps the wheel from spinning while you turn the wrench. Once the car is in the air, the wheel will spin freely and you cannot loosen the bolts. Loosen them a quarter turn, then lift the car, then remove them the rest of the way by hand.
The tire iron and breaking bolts loose
A tire iron is a flat metal bar, usually with a notch or slot on one end, used to pry the wheel off the hub after the bolts are removed. On many cars, the lug wrench has a tire iron built in as one of its flat sides. After you remove all the bolts, slide the tire iron under the edge of the wheel and gently pry it toward you. The wheel should come free from the hub.
If the wheel is stuck, do not force it. Spray penetrating oil around the edge where the wheel meets the hub and wait a few minutes. Rust or corrosion can cause wheels to stick, and forcing them can damage the hub. Once it loosens, the wheel should slide off easily.
Wheel chocks: keeping the car from rolling
A wheel chock is a wedge-shaped block placed behind the wheels to prevent the car from rolling. This is one of the most overlooked safety steps. Even on level ground, a car can roll if you are working on it and the parking brake fails or is not set firmly enough. Place chocks behind both rear wheels if you are changing a front tire, or behind both front wheels if you are changing a rear tire.
You can buy rubber or plastic chocks at any auto parts store, or you can use wooden blocks, bricks, or even large rocks in an emergency. The point is to have something solid behind the wheels before you lift the car. This takes 30 seconds and prevents a serious injury.
A torque wrench: tightening bolts to the right tension
A torque wrench is a specialized wrench that tightens bolts to a specific tension measured in foot-pounds. Your car's manual lists the correct torque specification for your wheel bolts — it is usually between 80 and 120 foot-pounds, depending on the vehicle. A torque wrench clicks or beeps when it reaches the target tension, so you know when to stop.
Bolts that are too loose can cause the wheel to wobble or fall off. Bolts that are too tight can strip the threads on the studs or crack the wheel. A torque wrench removes the guesswork. If you change your own tires regularly, a torque wrench is a worthwhile tool. For a one-time roadside change, hand-tightening the bolts firmly is acceptable — just make sure they are snug enough that you cannot turn them by hand.
Optional tools that make the job easier
A breaker bar is a long metal rod that slides over a lug socket to give you extra leverage for breaking tight bolts loose. If you have weak hands or the bolts are very tight, a breaker bar can save your hands from cramping. It is not essential, but it is inexpensive and useful if you struggle with the cross wrench.
A work light or headlamp is invaluable if you change a tire in the dark. A small LED flashlight or a headlamp that straps to your forehead keeps both hands free and lights the work area. Many roadside flats happen at night, so keeping a light in your car is practical.
A pair of work gloves protects your hands from sharp edges on the wheel and keeps your hands clean. Tire changing is dirty work, and gloves make cleanup easier. They also give you a better grip on the wrench if your hands are sweaty or oily.
Frequently Asked Questions
Can I use my car's scissor jack on gravel or dirt?
No. A scissor jack needs a hard, flat surface to sit on. On gravel or soft ground, the jack can sink and tip over. If you get a flat on a dirt road, place a flat board or piece of plywood under the jack to spread the weight and keep it stable.
What size lug wrench do I need?
Your car's manual lists the bolt size, but a cross-shaped lug wrench usually has four common sizes on it, so one will fit. If you buy a single-socket wrench, measure one of your wheel bolts with a ruler or take a photo to the auto parts store and they can match it for you.
Do I really need jack stands if I'm just changing a tire?
Yes. A jack can fail, slip, or be knocked over. Jack stands are cheap insurance. If you do not have them, change the tire with the car lifted but do not crawl under it. Many tire shops will loan you jack stands if you ask.
How tight should I make the bolts if I don't have a torque wrench?
Tighten them firmly by hand until you cannot turn them any further without straining. Then use the lug wrench to give each bolt a quarter turn more. They should be snug but not so tight that you need all your strength. Err on the side of slightly loose rather than extremely tight — you can always tighten them more at a tire shop later.
Should I carry a spare jack in my car?
The scissor jack that came with your car is usually enough. If you want a backup, a small hydraulic bottle jack takes up little space and is lighter than a floor jack. Keep it in the trunk with your lug wrench and you have a complete roadside kit.