Change a Car Tyre in 8 Simple Steps: A Roadside Guide

Changing a tyre at the roadside takes about twenty minutes if you have the right kit and a safe place to work. The part that catches people out is not the mechanical sequence, it is stopping somewhere sensible and slackening the wheel nuts before the car is jacked up rather than after.

The eight steps are below, along with the UK specifics that matter: legal tread limits, what to do if your car has no spare, and the one place you should never attempt this.

When does a car tyre need changing?

A tyre needs changing when the tread is at or approaching the legal limit, when the structure is damaged, or when it has aged out. Check for these:

• Tread below 1.6mm. That is the UK legal minimum across the central three quarters of the tread, right around the tyre. The quick check is a 20p coin: push it into the main grooves, and if you can see the outer band of the coin the tread is getting close to 3mm and it is time to plan replacements.
• Uneven wear. Wear concentrated on one shoulder points to alignment, and wear in the centre or on both edges points to over or under inflation. Fixing the tyre without fixing the cause just wastes another tyre.
• Bulges, splits or cuts. A bulge in the sidewall means the internal cords have failed. That tyre is not repairable and should be changed immediately.
• Vibration through the steering or the seat. Usually a balance problem, sometimes a separated belt inside the tyre.
• Repeated pressure loss. A slow puncture, a corroded rim seat or a leaking valve. All need investigating rather than topping up weekly.
• Age. Rubber hardens over time regardless of mileage. Check the four digit date code on the sidewall, and treat anything over about six years old with suspicion even if the tread looks fine.

What tools do you need to change a car tyre?

Before you need them, open the boot and confirm what your car actually carries. A surprising number of drivers discover on the hard shoulder that there is no spare under the boot floor.

• A spare wheel, correctly inflated. Space savers lose pressure sitting in the boot for years, so check it when you check the others.
• A jack, normally stored with the spare or in a side compartment in the boot.
• A wheel brace to slacken and tighten the wheel nuts or bolts.
• The locking wheel nut key if your car has locking nuts. This is the single most commonly missing item. It is often in the glovebox, the boot compartment or a wheel cover.
• Wheel chocks, or a solid block of wood, to stop the car rolling.
• Gloves, because wheels are filthy and braces bite.
• A torch, since a good proportion of punctures happen in the dark.
• A reflective jacket and a warning triangle. Compulsory in much of Europe and simply sensible here.
• The vehicle handbook, which tells you where the jacking points are and what the wheel nut torque figure is.

Two extras that are worth having: a small torque wrench, so the nuts go back on correctly rather than hopefully, and a foot pump or 12V compressor for checking pressures.

How to change a car tyre in 8 steps

Step 1: Stop somewhere safe and level

Pull well off the carriageway onto flat, firm ground and switch your hazard lights on. Level matters because a jacked car on a slope can shift, and firm matters because a jack sinks into soft verges and hot tarmac. Get any passengers out of the car and behind a barrier or well away from traffic. If it is dark, park so your lights or a torch illuminate the work.

Step 2: Secure the car

Put the handbrake on firmly and select first gear, or Park on an automatic. Chock the wheel diagonally opposite the one you are changing, in front of it if you are facing downhill and behind it if you are facing uphill. Never rely on the handbrake alone once one wheel is off the ground.

Step 3: Slacken the wheel nuts before you jack

Fit the locking wheel nut key first if you need it, then slacken each nut about half a turn, anticlockwise, with the wheel still on the ground. Doing this before jacking means the tyre grips the road and takes the torque instead of the wheel spinning. If a nut will not move, put steady weight on the brace with your foot rather than jerking it, and keep your body out of the way if it lets go suddenly.

Step 4: Position the jack and raise the car

Find the correct jacking point in the handbook. Cars have reinforced points on the sill just behind the front wheels and just ahead of the rear ones, usually marked with a notch or an arrow. Putting a jack anywhere else will fold the sill or crack the underside. Raise the car until the flat tyre is around 5cm clear of the ground so the fully inflated spare will fit under the arch.

Step 5: Remove the wheel

Take the nuts off completely, keeping them together in a pocket or the hubcap so they cannot roll away. Pull the wheel straight towards you. If it is stuck to the hub with corrosion, refit one nut a couple of turns, then tap the tyre sidewall with the heel of your hand or a rubber mallet to break it free. Lay the removed wheel flat under the sill near the jack, which gives you something to land on if the jack fails.

Step 6: Fit the spare

Lift the spare onto the hub and line the holes up with the studs or the threaded holes. On cars with bolts rather than studs, an old bolt with the head cut off makes a useful guide pin, though most people manage by resting the wheel on a foot. Start every nut by hand, several turns each, before touching the brace. Cross threading a wheel stud at the roadside turns a twenty minute job into a recovery truck.

Step 7: Lower the car and tighten properly

Wind the jack down until the tyre is touching but not carrying the full weight, then tighten the nuts in a diagonal or star pattern rather than going round the circle. This pulls the wheel onto the hub squarely. Lower the car fully, take the jack out and do a final tighten in the same pattern.

Step 8: Check the pressure and the torque

Check the spare's pressure at the first opportunity, since the correct figure for a space saver is often much higher than your normal tyres and is printed on the wheel or in the door shut. Retighten the nuts to the manufacturer's torque figure with a torque wrench when you get home or at the tyre fitter, and recheck them after 25 to 50 miles. Put the flat tyre, the jack and the tools back in the boot rather than leaving them loose in the cabin.

Where you should never change a tyre

Do not change a tyre on a motorway hard shoulder. It is one of the most dangerous places on the road network. If you get a puncture on a motorway, put your hazards on, pull as far left as you can, leave the car by the nearside doors, get behind the barrier and up the bank, and call for assistance. Do not stand between the car and the barrier and do not open the boot to fetch tools.

On a smart motorway with no permanent hard shoulder, aim for an emergency area if you can reach one. If you cannot, and the car will not move, keep your seatbelt on, keep your hazards on and call 999 rather than trying to get out into a live lane.

The same logic applies elsewhere in smaller doses. Avoid changing a wheel on a soft verge, on a camber that puts the car leaning towards you, on a bend where approaching traffic cannot see you, or anywhere the passing traffic is close enough to rock the car.

Space saver, full size spare or a sealant kit?

If your car came with a sealant kit and you cover a lot of rural miles, buying a manufacturer approved space saver kit with a jack and brace is worth considering. Check it fits the well under the boot floor and clears the front brake calipers, which is where some kits catch people out.

Can the damaged tyre be repaired?

Sometimes. In the UK, tyre repairs are carried out to a British Standard that sets out where a repair is permitted. Broadly:

• Repairable: a clean puncture in the central tread area, within the permitted repair zone, on a tyre that has not been driven flat.
• Not repairable: any damage to the sidewall or shoulder, cuts that reach the cords, bulges, a tyre that has run flat and overheated, or damage on a run flat tyre unless the manufacturer specifically allows it.

A fitter has to remove the tyre from the rim and inspect the inside before deciding, so a repair cannot be judged from the outside. Plug kits sold for roadside use are a get you home measure, not a permanent repair.

Also worth knowing: if you replace only one tyre, fit it on the same axle as its closest match, and put the two best tyres on the rear axle. A car with more grip at the front than the rear will oversteer in the wet, which is far harder to catch than understeer.

How to check your tyre pressures properly

Correct pressures do more for tyre life and fuel consumption than anything else you can do in five minutes, and under inflation is the main cause of roadside blowouts.

• Find the right figures on the sticker in the driver's door shut, inside the fuel filler flap, or in the handbook. Most cars list two sets: normal load and fully laden. Use the laden figures if you are carrying passengers and luggage.
• Check when the tyres are cold, meaning the car has been standing for a couple of hours or has covered less than a mile or two. Hot tyres read higher and will leave you under inflated once they cool.
• Do not trust forecourt gauges blindly. They take a hammering and drift. A cheap digital gauge of your own is more reliable.
• Check monthly and before long trips, and do not forget the spare.
• Reset the tyre pressure monitoring system afterwards if your car has one, or the warning light will stay on.

If one tyre keeps losing pressure, get the wheel checked rather than topping it up. Corrosion on the rim where the tyre bead sits is a common cause on older alloys, and it is a wheel refurbishment job rather than a tyre job.

Should you fit winter tyres in the UK?

Winter tyres make a real difference below about seven degrees Celsius, which covers a good part of a Manchester winter. The compound stays flexible when a summer tyre has gone hard, and the tread pattern clears water and slush better, so braking and cornering grip improve on cold wet roads as well as on snow.

Whether they are worth it depends on where and when you drive. They make most sense if you commute over the Pennines, live somewhere on a hill that does not get gritted, or drive a rear wheel drive car. For urban driving on treated main roads, a good set of all season tyres is often the more practical compromise, since you avoid storing and swapping two sets.

Two practical points. Fit winter tyres in fours, never on one axle only, because mismatched grip front to rear makes a car unpredictable. And remember that running two sets means two sets of wheels or two tyre changes a year, so factor the fitting and storage cost into the decision.

When to call for help instead

There is no prize for doing this yourself. Call your breakdown provider if:

• You are on a motorway, a dual carriageway with no safe verge, or a blind bend.
• The wheel nuts will not move, or the locking wheel nut key is missing or rounded off.
• The ground is soft, sloping or icy.
• The spare is flat, missing, or is not the right size for the car.
• The damage is more than a puncture, for example a shredded tyre that has taken the arch liner or a bumper with it.
• You are not confident. It is a twenty minute job when it goes well and a serious injury when it does not.

Is the alloy wheel damaged as well as the tyre?

Punctures and kerb strikes tend to arrive together, because whatever damaged the tyre usually caught the rim on the way past. Once the tyre is sorted, look at the wheel itself. Kerbing that has removed paint or lacquer will corrode, and on a diamond cut wheel the exposed aluminium goes milky under the lacquer within months.

We refurbish standard painted and powder coated wheels through our alloy wheel repair service, and we run a mobile diamond cut wheel repair service for the machined finishes that need a lathe. Both are done at your home or workplace across Greater Manchester, Lancashire, Cheshire, Merseyside and West Yorkshire, or at the body shop in Radcliffe.