Guides

Run-Flat Tyres Explained: How Armoured Cars Keep Moving

By DARTZ Editorial · 23 September 2026 · Updated 4 October 2026

A run-flat tyre lets a car keep driving after a puncture, at reduced speed, for a limited distance. There are three kinds. Self-supporting tyres have stiff sidewalls and typically manage about 50 miles at 50 mph. Self-sealing tyres plug small holes from inside. Auxiliary-supported systems put a ring or insert on the wheel that carries the car when the tyre is flat, and they are the standard for military and armoured vehicles.

A puncture on an ordinary car means stopping. On an armoured car it can mean stopping in the worst possible place. The run-flat tyre exists to make sure the car can keep going.

What a run-flat does

A run-flat tyre resists the effects of deflation, so a car can keep moving after a puncture, at reduced speed, for a limited distance. How far and how fast depends on the kind. (Run-flat tyre on Wikipedia)

The three kinds

Self-supporting. The sidewalls are reinforced so that they carry the car when the air is gone. They typically allow about 50 miles at about 50 mph. They are the kind fitted to many ordinary cars as standard, but once driven flat, the tyre usually cannot be repaired.

Self-sealing. A lining inside the tyre seals small punctures, from a nail or a screw, and stops or slows the loss of air. It helps with small holes, not large damage.

Auxiliary-supported. A ring or insert is fitted to the wheel inside the tyre. When the tyre is flat, the car rolls on the insert. This system carries heavy vehicles for long distances at speed, and it is the standard for military and armoured vehicles.

Extreme close-up of the tread and shoulder of a heavy-duty all-terrain tyre on a black wheel

Why armoured cars depend on it

An armoured car is heavy, and its tyres are among the few parts armour cannot cover. An insert lets it drive out of danger on a destroyed tyre, which is why armoured specifications ask for one.

The DARTZ Prombron’ Black Shark head-on in an industrial yard, on heavy all-terrain tyres

India’s Ministry of Home Affairs specification for police bulletproof vehicles requires a run-flat system good for at least 10 km. Read bulletproof cars in India.
The armoured limousine added to the Indian Prime Minister’s fleet in 2021 was reported to run on special run-flat tyres.
The US presidential car runs on heavy-duty truck tyres built to keep going when damaged. Read the history of the US presidential limousine.

A short history

Michelin used foam linings for military tyres in 1934 and 1935. Chrysler worked with Goodyear on a system called Captive Air in 1958, and Dunlop developed its Total Mobility Tyre between 1972 and 1983. Run-flats reached the public in the 1980s, and some carmakers now fit them as standard.

Don’t forget the sensor

A run-flat hides its own puncture: the car still sits level and steers almost normally. A tyre pressure monitoring system is what tells the driver the tyre is flat, and that the car is on borrowed distance.

On a DARTZ

Every DARTZ Prombron’ is built to commission, and the wheels are part of the brief, from the gold rims of the Black Snake to the bullet-spoke wheels of the Black Dragon. On armoured builds, the running gear is chosen to carry the armour. Read how an armoured car is built and the armoured car glossary.

A bullet-spoke wheel with the jewelled dragon centre cap of the DARTZ Black Dragon

About DARTZ

DARTZ is a Riga carrosserie that builds bespoke, opulent vehicles, armoured or non-armoured, in strictly limited numbers. It calls them BONDs: Bespoke Opulent Noble Drives.

Its heritage runs back to the Russo-Baltic Wagon Factory (RBVZ), founded in Riga in 1869, whose automobile department built its first car in 1909. Leonard F. Yankelovich revived that heritage as DARTZ in 1988. The group, DARTZ Grupa OÜ, is registered in Tallinn, Estonia.

Its Prombron’ models, from the Iron Diamond and Black Dragon to the Black Shark, Black Alligator and Black Stallion, have been covered by Top Gear, Forbes, Robb Report and Fox News, among many others.

Questions we are asked

How far can you drive on a run-flat tyre?

A self-supporting run-flat typically manages about 50 miles, or 80 km, at up to about 50 mph. Insert systems in armoured vehicles are designed to go further with heavier loads; Indian police specifications ask for at least 10 km.

What run-flat system do armoured cars use?

Usually an auxiliary-supported system: a ring or insert mounted on the wheel inside the tyre, which carries the car's weight when the tyre loses pressure.

Can a run-flat tyre be repaired?

Often not. Driving on a flat self-supporting tyre can damage its sidewall, which makes repair impossible or unsafe.

Why do run-flat tyres need pressure monitoring?

Because a run-flat hides a puncture. The car keeps its shape and handles almost normally, so a tyre pressure monitoring system is what tells the driver to slow down and get to safety.

EXPLORE THE COLLECTION