Run-flat markings (RF, RFT, ROF, SSR, ZP, RSC)
A run flat or self-supporting tyre: its reinforced sidewall carries the car after a loss of pressure, for at least 80 km at up to 80 km/h in the regulation’s definition.
What to do with it
Replace run-flats with run-flats unless the vehicle maker says otherwise; Pirelli notes that cars fitted with them do not typically come with a spare. Watch the tyre-pressure warning, which is how you learn of a puncture. Repair rules are the tyre maker’s: Michelin, for one, allows a single repair by a professional.
- What it looks like
- An F in the size (205/55 RF16), and the maker’s own name for the technology: ZP or EMT on Michelin, SSR on Continental and Uniroyal, RSC in a circle on Pirelli, and letters such as RFT and ROF on other makes.
- Set by
- UN Regulation No. 30, paragraphs 2.3.7 (definition of ‘Run flat tyre’), 3.1.3.5 and 3.1.12
In detail
- UN R30 defines the run flat or self-supporting tyre as supplying the basic tyre functions “at least, at a speed of 80 km/h (50 mph) and a distance of 80 km” when flat, and marks it with F in front of the rim diameter (3.1.3.5) and a symbol of its own (3.1.12).
- Michelin: its run-flat tyres carry ZP (Zero Pressure) or EMT (Extended Mobility Tyre), may only be mounted on double-hump rims on vehicles approved for them, and need a pressure monitoring system.
- Pirelli: run-flats carry “the letters RSC (Run Flat System Component) surrounded by a circle”, and acronyms such as RFT (Run Flat Technology), SSR (Self Supporting Run Flat) and ROF (Run On Flat) identify run-flats.
- Uniroyal (Continental group) calls its version SSR and says run-flats can be identified by the letter F on the sidewall.
What it does not mean
A run-flat marking does not mean you can keep driving normally after a puncture: the regulation’s figure is 80 km at up to 80 km/h, and the maker’s limits apply. RF inside the size is not the same as reinforced (XL).
Markings that go with it
Sources
Each document was fetched and read on the date shown; the clause is the one that sets this marking.
- UNECE, as published in the Official Journal of the EU: UN Regulation No. 30 — Uniform provisions concerning the approval of pneumatic tyres for motor vehicles and their trailers, Revision 3 (OJ L 201, 30.7.2008) — paragraphs 2.3.7 (definition of ‘Run flat tyre’), 3.1.3.5 and 3.1.12: “‘Run flat tyre’ or ‘Self supporting tyre’ describes a pneumatic tyre structure … allowing the pneumatic tyre … to supply the vehicle with the basic tyre functions, at least, at a speed of 80 km/h (50 mph) and a distance of 80 km”; “the letter ‘F’ placed in front of the rim diameter marking”. Checked 2026-09-28.
- Michelin (UK): Runflat tyres help in the event of a puncture. What are they? — Michelin codes: “MICHELIN’s runflat tyres for sale have a ‘ZP’ or ‘EMT’ code on them: ZP for Zero Pressure, EMT for Extended Mobility Tyre.” Checked 2026-09-28.
- Pirelli (UK): Run Flat Tyres: What They Are and How to Identify Them — “How to identify run flat tyres”: The sidewall shows “the letters RSC (Run Flat System Component) surrounded by a circle”, and “acronyms such as RFT (Run Flat Technology), SSR (Self Supporting Run Flat) and ROF (Run On Flat) will tell you that the tyre is a run flat”. Checked 2026-09-28.
- Uniroyal (Continental group): Self Supporting Runflat (SSR) — FAQ: “Run-flat tyres can be identified by the letter ‘F’ on the sidewall.” Checked 2026-09-28.