Run-Flat Tyres: What Drivers Need to Know
A run-flat is designed to retain some mobility after losing air, giving you a chance to reach a safe place or a tyre professional. It is not puncture-proof, and the safe response depends on the tyre, vehicle and circumstances.
How a run-flat differs from an ordinary tyre
Self-supporting run-flats use reinforced sidewalls to carry the vehicle for a limited period after air pressure is lost. Manufacturers use different sidewall markings: Michelin, for example, uses ZP and EMT. Check the exact marking and the vehicle handbook rather than assuming any stiff-looking tyre is a run-flat.
Because the tyre can still look and feel supported while deflated, a working tyre-pressure monitoring system (TPMS) is essential to alert the driver. A run-flat does not remove the need to investigate a warning.
What to do after a pressure warning
Ease off, avoid abrupt manoeuvres and stop somewhere safe to assess the situation. If you cannot confirm that the tyre is a compatible run-flat, or handling is unstable or there is visible damage, do not assume you can drive on it; arrange assistance.
For a confirmed run-flat, consult the tyre and vehicle manufacturers' instructions for the applicable reduced-speed and distance restrictions, and head to a safe inspection point. Available mobility varies with the tyre design, vehicle load, road and temperature; it is not permission to finish an ordinary journey.
Check compatibility before changing tyre type
Do not assume run-flats can simply be fitted to any car. Michelin specifies vehicle approval, suitable rims and TPMS for its self-supporting tyres; vehicle suspension and handling may also have been designed around the original tyre type. Ask a qualified fitter to check the vehicle maker's approved specification before changing from conventional tyres or vice versa.
TyreSafe advises against mixing self-supporting run-flat and conventional tyres. If you need to replace one tyre, have the remaining tyres and vehicle requirements checked before deciding what to fit.
Inspection and possible repair
A run-flat that has been driven with little or no pressure may have damage that cannot be assessed from the outside. Tell the fitter about the warning and how the tyre was used; a proper decision requires examination, including the inside of the tyre.
Repair is not guaranteed: the manufacturer's policy, any no-repair marking, damage location and the tyre's condition all matter. Michelin says repair may be possible for some of its run-flats under defined conditions, but not in every case. For general puncture causes and checks, see the related puncture guide.
Related tyre-care guides
- What Causes Tyre Punctures?
- How to Check Tyre Pressure
- How to Read Your Tyre Size
- Signs Your Tyres Need Replacing
Compare tyre types and labels
Sources and further reading
This general guidance draws on the manufacturer and UK safety sources below. Your vehicle handbook and the instructions for your exact tyre take priority.