The quick answer
Compare readings under consistent conditions using the vehicle’s recommended pressure. Persistent loss, especially in one tyre, needs professional investigation. If it is flat, visibly damaged or rapidly deflating, stop using it and arrange appropriate assistance.
Make the readings meaningful
Check the pressure recommended for your vehicle and loading condition in the handbook or vehicle label. Do not use the maximum pressure moulded onto the tyre as your default setting. Measure under the conditions the manufacturer specifies, usually with cold tyres, and use a reliable gauge. Michelin explains when and how to check pressure.
Write down which tyre was checked, the reading, date and whether the vehicle had recently been driven. Mixing hot and cold readings or different gauges can make the pattern harder to interpret.
Possible causes, not a diagnosis
| Possible source | Information to tell the professional |
|---|---|
| Penetration or tyre damage | A visible embedded object, impact or when the loss began. |
| Valve or valve-to-wheel sealing | Any recent work or visible valve damage, without dismantling it. |
| Tyre-to-rim sealing or wheel condition | A pothole strike, corrosion noticed during previous work, or past wheel damage. |
| Changing conditions or inconsistent readings | The temperature/driving conditions and gauges used. |
Michelin identifies several possible leakage points in the tyre and wheel assembly. The table helps you describe the history; it does not establish which part is at fault.
Why repeatedly adding air is not a repair
Topping up restores a reading temporarily. It does not remove a nail, repair an unsuitable puncture, restore damaged reinforcement or address a leaking wheel interface. A tyre may lose pressure at a different rate on the next journey.
Do not assume that holding air overnight proves the tyre is sound. If it has been driven significantly underinflated, internal damage may need assessment. Tell the professional about that driving rather than judging the tyre only by its current appearance.
Treat a warning light as a prompt to investigate
Follow your vehicle handbook when a tyre-pressure warning appears. Check the actual tyre pressures and condition at a safe location. Do not simply reset the system to make the light disappear.
If measured pressures are correct but the warning persists, the monitoring system may also require attention. A tyre replacement is not a guarantee that every TPMS fault will be resolved; describe the warning and any recent tyre or sensor work.
Know when the situation is urgent
Do not continue using a conventional tyre that is flat or rapidly deflating. A visible outward bulge, exposed reinforcement or serious impact damage also needs urgent professional assessment. Arrange assistance or recovery according to the location rather than driving further to test it.
Where a run-flat system or temporary kit is involved, follow the specific manufacturer instructions and disclose what has been used. These are not universal permissions to drive with low pressure.
Prepare an enquiry that helps find the next step
- Registration, affected wheel and full tyre marking if safely accessible.
- Readings and how often you have had to add air.
- Any impact, embedded object, sealant use or recent tyre work.
- Warning messages and whether the vehicle was driven when low.
- Current location and whether the vehicle can be worked on safely.
Fix My Tyre provides replacement, not puncture repairs. If the problem turns out to be a wheel, valve or monitoring-system fault, discuss the appropriate assessment and service before assuming a new tyre is the complete solution.
Common questions
Does nitrogen stop a puncture leaking?
No. It does not seal a damaged tyre or a leaking valve or rim interface. The source of loss still needs investigation.
Should I remove the nail before calling?
No. Describe it and let a competent professional assess it. Removing it can increase the loss of pressure.
Is every pressure warning a puncture?
No. Check the actual pressures and follow the vehicle instructions. A warning can have more than one cause.
Sources and further reading
Guidance checked on 10 October 2026. Use the current official instructions for your vehicle and circumstances.