A flat tire has exactly three endings. The spare goes on and you drive away. The tire is repaired where it sits and you drive away. Or the vehicle is carried to a tire shop, because neither of the first two is available or safe.
Which ending you get is decided by two things: what the vehicle is actually carrying in the back, and what kind of damage the tire has. Most drivers do not know the first and cannot judge the second, so they call for the wrong service.
What is actually in your vehicle
Check this before you ever need it, because a roadside shoulder is a terrible place to discover the answer.
A full size spare. Increasingly rare, and the best outcome. It goes on, it has no speed or distance restriction of its own, and the day continues.
A temporary spare. Narrow, different in appearance, and carrying its own limits on speed and distance which are printed on it. It is a way to reach a tire shop, not a replacement wheel. It also tends to have been sitting under the trunk floor losing pressure for years, so it can be flat when you find it.
A sealant kit and a compressor. Now the standard fitment on a large share of new vehicles. It handles a small puncture in the tread and nothing else.
Nothing at all. More common than people believe, particularly where a previous owner used the spare and never replaced it.
Also check that the jack, the wrench and the locking wheel nut key are all present. The missing locking nut key is one of the most common reasons a straightforward wheel change stops dead at the roadside, and no operator can conjure one.
What kind of damage decides everything else
Tires are repairable in the tread area, within limits on the size of the puncture. They are not repairable in the shoulder or the sidewall, because that part of the tire flexes constantly and no repair there is trustworthy.
That single fact settles most cases. A nail in the middle of the tread is a candidate for a repair. A cut, a bulge, a gouge or an impact mark on the sidewall is not, whatever the tire looks like from a distance.
Two further conditions rule out both a repair and a sealant kit. A tire that has come off the bead needs to be reseated on a machine, not on a shoulder. And a tire that has been driven on while flat, even for a short distance, is usually destroyed internally regardless of how small the original puncture was: the sidewall has been folded and chafed against itself, and that damage is not visible from outside.
Sealant has its own boundaries. It is for small tread punctures. It does nothing for sidewall damage, a large hole, or a tire off the bead, and it makes the later permanent repair messier for whoever does it.
Heat, debris and why this happens here
Two Las Vegas conditions turn a slow leak into a failure.
Heat is the first. An underinflated tire flexes more than it should, flexing generates heat, and it is being run on pavement that is already far hotter than the air. That combination is what turns a tire that has been low for weeks into a blowout on a long, fast run rather than a slow deflation in a parking lot.
Debris is the second. Construction corridors and industrial routes collect fasteners, offcuts and wire, and the high speed sections of the valley’s freeways are where a punctured tire fails rather than simply leaks. That is also the worst possible place to be standing, which is covered in our guide to a Las Vegas freeway breakdown.
The practical defence is dull and it works: check pressures cold, monthly, including the spare. A tire pressure monitoring system warns you when a tire is already well down, which is later than you would choose.
When a flat tire becomes a tow
The vehicle gets carried rather than changed in these cases.
There is no usable spare, or the spare is flat, or the locking wheel nut key is missing. The damage is in the sidewall or the tire is off the bead, so a roadside fix would be pretending. The vehicle has run-flat tires, which are designed to be driven a limited distance at reduced speed after a loss of pressure and are usually not repairable afterwards. More than one tire is flat. The wheel is seized to the hub by corrosion and will not come off without persuasion that should not happen on a shoulder. Or the vehicle is somewhere a wheel change should not be attempted at all.
That last one overrides everything else. A wheel change puts a person kneeling beside a jacked vehicle. If that position is on the traffic side, on a slope, on soft ground, or on a shoulder narrow enough that a passing truck’s air blast can be felt, the right answer is to load the vehicle and do the work somewhere else. That is standard passenger work under light duty towing, and where a change is safe and possible it is a roadside assistance visit instead.
If you are changing it yourself
Park as far off the road as the vehicle will reach, on the firmest and most level ground available. Hazard lights on. Work from the curb side if there is any traffic at all, and move everyone else away from the vehicle rather than having them stand beside you.
Use the jacking points the manufacturer specifies. They are marked on most vehicles, usually as a notch or a reinforced pad on the sill, and a jack placed on a floor pan, a suspension arm or a plastic panel will fold something expensive. Loosen the wheel nuts slightly before the wheel leaves the ground and tighten them properly after it is back down, working across the wheel rather than around it.
Never get any part of your body under a vehicle supported only by a jack. And have the wheel nuts re-torqued properly once you reach a shop, because that is the step everyone skips.
What to tell the dispatcher
Where the vehicle is and which side of the road. Whether it is on a shoulder, in a lane, or in a lot. Which wheel is flat, and whether it is on the traffic side. Whether there is a spare, what kind, and whether the jack, wrench and locking nut key are present. Whether the vehicle was driven on the flat, and how far. And the make and model, because run-flat fitment and locking nut design vary.
Out on the desert highways the same failure has different consequences, which is covered in our guide to a desert highway breakdown. The full set of service lines is on our towing and transport services page, and dispatch is reachable through contact us.
Frequently asked questions
Can a flat tire be repaired at the roadside?
Sometimes, and only within limits. A small puncture in the tread area is a candidate. Damage in the shoulder or the sidewall is not repairable at all, because that part of the tire flexes constantly and no repair there can be trusted. A tire that has come off the bead needs a machine to reseat it, and a tire that has been driven on while flat is usually destroyed internally even if the original puncture was small.
My car has a sealant kit instead of a spare. Is that enough?
For a small tread puncture, often yes. For anything else, no. Sealant does nothing for sidewall damage, a large hole or a tire that has come off the bead, and it makes the permanent repair messier for whoever does it later. If the damage is outside what sealant handles, the vehicle needs to be transported rather than patched on the shoulder.
Why would a flat tire need a tow rather than a wheel change?
Because of what is missing or where you are. No usable spare, a flat spare, a missing locking wheel nut key, sidewall damage, run-flat tires, more than one flat, or a wheel seized to the hub all rule out a roadside change. So does position: a wheel change on the traffic side, on a slope, on soft ground or on a narrow shoulder should not be attempted, and loading the vehicle is the safer answer rather than the expensive one.
How far can I drive on a temporary spare?
Only as far as the limits printed on the spare itself allow, and they cover both speed and distance. A temporary spare is a way to reach a tire shop, not a replacement wheel, and it changes how the vehicle handles and brakes. Check the pressure in it too: temporary spares sit under the trunk floor for years losing air, so a substantial number of them are already flat when they are finally needed.
Why do tires fail so often on Las Vegas freeways?
Underinflation plus heat plus speed. A tire that is low flexes more than it should, that flexing generates heat, and the pavement is already far hotter than the air. A tire that would have gone slowly flat in a parking lot instead fails on a long fast run. Road debris on construction and industrial corridors supplies the puncture in the first place. Checking pressures cold once a month, including the spare, prevents most of it.