Run-flat tire guide

What is a run-flat tire?

A run-flat tire has reinforced sidewalls that support the vehicle's weight even after a complete loss of air pressure. This allows you to drive to a safe location or tire shop — typically up to 80 km (50 miles) at a maximum of 80 km/h (50 mph) after a puncture. Most new BMWs, MINIs and some Mercedes models are fitted with run-flats from the factory, meaning they carry no spare wheel. Run-flats are identified by markings such as SSR (BMW), RFT, ZP (Michelin), or ROF (Bridgestone).

How run-flat tires work

Standard tires rely entirely on air pressure to carry the vehicle load. When pressure is lost, the sidewall collapses and the tire is destroyed within seconds of driving.

Run-flat tires use one of two main technologies:

Self-supporting (SST) — the most common type. Extra-stiff reinforced rubber inserts in the sidewall carry the load even at 0 PSI. The sidewall is visibly thicker than a standard tire.
Support ring (SRT) — a hard ring attached to the wheel rim that the tire rests on if pressure is lost. Less common; used on some high-performance vehicles.

Key limits: After a pressure loss, run-flats must only be driven at ≤ 80 km/h (50 mph) for a maximum of 80 km (50 miles). Exceeding these limits causes irreparable sidewall damage and is dangerous.

Run-flat markings by brand

Brand	Code on sidewall	Full name
BMW / MINI	SSR	Self-Supporting Runflat
Michelin	ZP	Zero Pressure
Bridgestone	ROF	Run On Flat
Goodyear	ROF / EMT	Extended Mobility Technology
Continental	SSR	Self Supporting Runflat
Pirelli	r-f / RFT	Run Flat Technology
Dunlop	DSST	Dunlop Self-Supporting Technology

Run-flat vs conventional tires

Aspect	Run-flat	Conventional
Spare wheel	Not required — saves boot space and weight	Required (or foam kit)
After puncture	Continue driving up to 80 km at ≤ 80 km/h	Must stop immediately
TPMS requirement	Mandatory — no tyre-pressure feedback without it	Recommended but not legally required everywhere
Ride comfort	Firmer; stiffer sidewalls transmit more road noise	Softer; more compliant sidewall
Purchase cost	20–50% more expensive per tire	Lower
Repairability	Most manufacturers advise replacement, not repair	Puncture repair often possible (if in tread area)
Weight	Heavier (reinforced sidewall)	Lighter

Can you repair a run-flat tire?

Most tire manufacturers and vehicle OEMs state that run-flat tires should not be repaired after a pressure loss event. The reason: when the reinforced sidewall operates at 0 PSI, internal heat and stress may cause invisible structural damage that cannot be assessed visually.

Some tire shops will repair a run-flat if it has been driven under the speed/distance limits and the puncture is in the central tread zone (not the sidewall). However, any repair voids the run-flat warranty and is not recommended by most manufacturers. When in doubt, replace.

Can I replace run-flat tires with conventional tires?

Technically yes, but with important caveats:

Your car was designed without a spare. If you switch to standard tires, you have no fall-back after a puncture. You would need to carry a foam tire sealant kit or portable compressor — neither replaces a spare for structural damage or sidewall cuts.
TPMS is still mandatory. You will still receive pressure warnings.
Suspension tuning on many run-flat-equipped cars is stiffer than average to compensate for the run-flat's stiff sidewall. Switching to softer standard tires may make the ride feel bouncier or less planted in corners.
If you switch, replace all four at once — mixing run-flat and conventional on the same axle is unsafe.

Do run-flat and conventional tires wear differently?

Run-flat tires typically wear slightly faster than equivalent conventional tires due to the stiffer compound needed to maintain sidewall integrity. Expect roughly 10–20% shorter tread life in everyday driving. Tire rotation every 5,000–10,000 km is especially important for run-flats to even out wear across axles.

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Last reviewed: 2026-06-21