How to change a tire

Getting somewhere you can work

The surface matters more than the distance. A jack needs level, firm ground: on a slope the car can roll off it, and on soft ground or gravel the jack sinks and tips.

It is worth driving a short distance on a flat tire to reach somewhere safe. You will destroy the tire and possibly damage the wheel, and both are cheaper than the alternative. A shredded tire is a purchase; a car falling off a jack is not.

1. Hazard lights on immediately
2. As far off the carriageway as you can get, wheels straight
3. Parking brake on, park or first gear
4. Everyone out on the side away from traffic, behind a barrier if there is one
5. Triangles out — best warning triangles and road flares

The jacking points, which are not obvious

This is the step most likely to go wrong on a modern car. Jacking points are specific reinforced locations, usually just behind the front wheels and just ahead of the rear ones, often marked by a notch, an arrow or a molding in the plastic sill trim.

Lifting anywhere else — the sill panel between the points, the floor pan, a suspension arm, a subframe edge — will bend metal, and a jack on a surface that deforms is a jack that can slip out.

The owner's manual has a diagram. Look at it now rather than at the roadside in the dark, and take thirty seconds to find your car's points while you are somewhere comfortable.

Why the nuts come loose before the lift

Lug nuts are tight, and loosening them takes real force. With the wheel on the ground, the tire's friction against the road holds it while you turn the wrench.

Once the wheel is in the air, nothing holds it. The wheel simply rotates, and you end up pushing hard against a car balanced on a jack — which is exactly the situation that shifts a jack.

A quarter turn each is enough. Do not remove them; just break them free. If a nut will not move, standing on the wrench with a foot is a common approach — but be aware that a wrench slipping under body weight is how people get hurt, so keep your face and hands clear.

The rule that has no exceptions

Never put any part of your body under a car supported only by a jack. Not an arm, not a leg, not your head. A jack is a lifting device, not a support device, and it can fail or slip.

The practical mitigation costs nothing: once the wheel is off, lay it flat under the sill near the jacking point. If the jack fails, the car drops onto the wheel rather than onto the ground — or onto you.

Also lift only as far as you need. An inch of clearance is plenty, and a car high on a narrow jack is less stable than one barely lifted.

The star pattern, and what it is for

Tighten opposite nuts in sequence rather than going around the circle — on a five-stud wheel that means a star, on a four-stud wheel a criss-cross.

The reason is that a wheel has to seat flat against the hub. Tightening around the circle pulls one side down first and can cock the wheel very slightly, which produces a vibration at speed and uneven stress on the studs.

Do the final tightening with the wheel on the ground taking the car's weight. Fully torquing nuts while the wheel is still in the air pushes against a jacked car again, which is the thing to avoid.

Get the nuts checked with a proper torque wrench soon after. Under-tightened nuts can work loose; over-tightened ones stretch studs and are the reason a nut sometimes will not come off at the roadside at all.

The spare, and its limits

A space-saver spare is a temporary wheel with limits printed on it — commonly a speed limit around 50 mph and a distance limit. Those are on the wheel itself; read them before driving off.

Two other things people find out too late. A spare that has sat for years is very often well below usable pressure, so check it with a gauge — AstroAI publishes plus or minus 1 PSI against ANSI B40.7, which is a stated accuracy figure almost nothing in that category offers. See best tire pressure gauges.

And many cars no longer carry a spare at all — a sealant kit and an inflator is increasingly the factory provision. If that is your car, this page is not your procedure, and best tire repair kits is.

What makes this easier

• A flashlight, hands-free. Punctures happen at night. Anker publishes 900 lumens and IPX5 for the Bolder LC90 — best flashlights for a car
• Gloves. Wheels are filthy and hot, and brake dust is not something to have on your hands
• A gauge and an inflator, for the spare — best tire inflators
• A high-visibility vest, kept in the cabin so you can put it on before getting out
• A mat or a piece of cardboard to kneel on

Most of that is in a pre-packed kit — best emergency car kits. Keep the spare and jack accessible rather than buried under luggage, which is the recurring road-trip failure covered in how to pack a car for a road trip.