What are run-flat tyres and do they keep you safe?
Run-flat tyres could mean the difference between harm and driving to safety after getting a puncture. Loss of vehicle control and risk of rim damage dictate that you stop but when your life depends on it, you keep driving. Run-flat tyre tech solves this conundrum, letting you continue your journey until you reach safety.
In crime-ridden South Africa, life is fast and, sadly, cheap. You don’t dare drive at night. And even when the traffic lights do work, you don’t stop unless absolutely necessary. Still, it only takes one dead streetlight and a perfectly placed pothole to cause a puncture. You have to weigh up the risk of stopping and being subjected to a criminal attack during a tyre change; or continue driving to a safer spot while damaging your car. This is where run-flat tyres (RFTs) come in, and if you get a puncture in an unsafe area, the tech could save your life.
How run-flat tyres work: Technology that keeps you moving after a puncture
It’s a horrible feeling. Whether you’ve driven over a nail, struck a kerb or crashed through a crater – the soundtrack and the sensation is always the same: deflation before the onset of offset steering. This is the after-effect of a normal road tyre that’s lost all its air and is compressing under the weight of the vehicle.
RFTs, though, are designed to prevent just that from happening.
Any tyre’s weakest point is its sidewall, which by design comprises thinner rubber and less internal protection than the road-facing tread section. They’re designed this way to enable bump absorption and flexing as an extension of a vehicle’s mechanical suspension.
Read more: Tyre maintenance tips
Therein lies the key difference. An RFT has a reinforced sidewall featuring additional support from extra rubber inserts and other load-bearing materials. These lessen structural deformation born from excessive friction and heat that would ordinarily compromise vehicle handling: the fastest way to destroy a normal tyre had you kept on driving after a puncture.
Run-flat tyres vs standard tyres: The key differences every driver should know
| Attribute | Run-flat tyres | Normal tyres |
| Puncture-handling ability | Can drive 50-80 km (at up to 80 km/h max) after a puncture | Requires an immediate stop and change |
| Sidewall design | Reinforced; supports car weight even when punctured | Flexible; collapses without air |
| Ride comfort | Firmer; transmits more bumps | Softer/smoother; better bump absorption |
| Weight | Heavier (approx. 20- 30% more) | Lighter |
| Fuel efficiency | Slightly worse due to increased weight | Generally better |
| Repairability | Rarely repairable if driven while flat | Usually repairable (if tread only, but damage dependent) |
| Spare wheel | Not required (frees up boot space) | Crucial(takes up boot space) |
Read more: Essential Emergency Supplies for Your Car
How run-flat tyres affect ride comfort & handling
While most medium- to high-spec BMWs, Mercedes-Benz models and Audis (and increasingly some Chinese brands) have them, the critical caveat is that if your model isn’t fitted with tyre pressure monitors (TPMS), as a rule you cannot fit run-flat tyres. Doing so might even void your car’s factory warranty.
That’s because, bizarrely, RFTs do their job of minimising post-puncture vehicle behaviour change too well. Basically, without being informed of a deflated tyre, you could continue driving at regular speeds over extended distances well beyond the RFT’s inherent – but ultimately still-fallible – safety margin. By then, rim damage is inevitable and a sudden high-speed direction-change would be catastrophic.
Read more: Safety systems for cars explained
With the TPMS hurdle cleared (and additional replacement cost aside), if you do decide to upgrade your next set of tyres to RFTs, other compromises are worth noting.
The extra reinforcement makes RFTs heavier and noisier than regular tyres. In turn, the additional weight will make your car’s steering feel initially sharper but more prone to annoying feedback from the road surface (i.e. not the good kind).
Furthermore, with pliance traded for sidewall durability, RFTs can crash over bumps rather than absorb them, which are transmitted into the vehicle cabin – a trade-off that can be answered only by each individual’s driver’s tolerance levels of discomfort. That said, the newest and best RFTs have addressed this concern to an impressive degree by balancing sidewall strength and compliance.
Read more: Fuel efficient driving tricks and techniques
Potentially putting, uhm, the final nail in the case for fitting RFTs is the fact that the additional rolling resistance owed to the extra weight and stiffness causes heat that reduces tyre life, meaning that not only are you paying more initially (and using more fuel because of the extra mass) than for normal tyres, you’ll also be replacing them more regularly.
On the plus side, RFTs are an essential peace-of-mind purchase if you don’t know how to change a tyre and don’t have anyone to call (or who’ll answer at 2am). And because the tyre retains its shape after a puncture, vehicle stability remains largely unaffected.
Do RFTs fit your car? Compatibility, costs & what to expect
Unsurprisingly, RFTs are pricier than all but (in some instances) the most premium iteration of their standard equivalents.
| Tyre size / type | Standard tyre price range | Run-flat tyre price range |
| 16-inch (budget) | R850 to R1 300 | R2 100 to R2 800 |
| 17-inch (mid-range) | R1 400 to R1 900 | R2 600 to R3 500 |
| 18-inch (premium) | R1 800 to R2 600 | R3 200 to R4 800 |
| 19-inch+ (luxury/SUV) | R3 500 to R5 500 | R6 000 to R12 000+ |
Still interested? No doubt, run-flat tyres aren’t without compromise. They’re heavier, firmer and pricier than regular rubber. But think of them as the roadside assistance you never knew you needed: they won’t make potholes disappear, but they might just let you laugh off a puncture instead of stressing over it when you least have to.
Read more: Tyre insurance: How to protect your wheels and your wallet