Considering that your tyres are the only point of contact between your car and the ground as you’re travelling at high speeds, you want to make sure they can get you where you want to go – in one piece. Run-flat tyres (RFTs) come with a fail-safe get-you-home function, but do you really need them? Are they worth the investment? We’ll discuss the advantages and disadvantages of run-flat tyres to help you make a decision.
For quick navigation, we’ll cover the following points in this post:
- What are run-flat tyres?
- How do run-flat tyres work?
- Are run-flat tyres expensive?
- The benefits and disadvantages of run-flat tyres
No one wants a flat tyre. They’re the worst. But as a motorist, chances are that at some point in your driving career, you’ll come to suffer the inconvenience of having to deal with a tyre puncture.
Imagine you’re on your way into a well-deserved long weekend on the beach. You’re leaving the city behind you and turning onto the highway. At this point, you’re probably going 100 km/h. That’s when you suddenly hear a petrifying bang followed by a whooshing noise coming from around the passenger door side. Staying level-headed, you manage to stop safely on the side of the road. You get out of the car and to your great concern, see that the tire on the passenger side is completely shredded.
Now, there are two possible endings to this story, and they depend on one factor: Does your car have run-flat tyres or not?
If the answer is yes, congratulations! You don’t have to sit around and wait for the RACQ to arrive and help you out of the pickle you’re in. Since a punctured run-flat tyre doesn’t immediately require changing, you can continue to drive to a nearby tyre service centre or a trustworthy, certified mechanic.
But if you blow a regular tire on the highway, a scary situation can quickly become hazardous for you, your passengers and anyone else on the road. Not to mention that not all of us are comfortable changing a tyre on the side of a busy road, which means waiting for roadside assistance. On weekends, during holidays, or the middle of the night, you can easily be stuck on the side of the highway for hours and hours.
What are run-flat tyres?
As the name suggests, run-flat tyres can run without air pressure if the tyre has been punctured, burst or blown out. At reduced speed (usually up to 90km/h) and for limited distances (around 16km to 80km), they safely take you to your next destination.
The technology was first introduced by Michelin in 1934 and later used for military purposes during WWII. As part of bullet-proofing tactics, RFTs ensured that vehicles could continue travelling and get their passengers to safety, even if the car had been shot at.
When run-flat tyres first hit the streets, the technology was still very clunky. In the early days, run-flat tyres were expensive, loud and felt sharper than traditional tyres. They weren’t worth the coin you paid for them and left many drivers unsatisfied. Until decades, and many iterations later, tyre manufacturers finally got the hang of it.
Nowadays, RFTs barely impact ride and handling compared to regular tyres. Most recently, most of the newer models of the German car manufacturer BMW come fitted with Bridgestone and Pirelli run-flat tyres. Mercedes, Audi, Lexus, and Mini models are often supplied with run-flat tyres, too. The automakers promote these as a safety feature and practical alternative to carrying a spare tyre.
There are two main types of run-flat tyres commonly used today. They either rely on a self-supporting or support ring system. What’s the difference between these two types of RFTs, you’re wondering? To answer this question, we need to take a look at how they work.
How do run-flat tyres work?
The two common types of RFTs currently available are self-supporting tyres with strengthened sidewalls and tyres with an internal support ring, often also referred to as auxiliary-supported run-flat tyres.
Self-supporting tyres use special interlinings to support and reinforce the tyres’ inner sidewalls.
Walls reinforced with thick rubber hold the tyre’s form even if the tyre itself is punctured or deflated. Today, self-supporting run-flat tyres are commonly offered as standard equipment for light trucks and passenger cars. German car manufacturers such as BMW and Audi swear by self-supporting RFTs and use them as standard on most of their current models.
The second type of run-flat tyres uses a separate ring of hard rubber that is attached to the wheel. When the tyre’s sidewall collapses, it cushions the rim so that the turning wheel only touches the sidewall, never the road. These auxiliary-supported tyres can carry the weight of a car over long distances, even if the tyre is completely deflated. For their ability to carry heavy vehicles at high speeds, they’re the default run-flat option for military vehicles used in conflict zones, bullet-proof cars driven by government officials and private sector VIPs.
Are run-flat tyres expensive?
Yes, run-flat tyres are slightly more expensive to replace than regular pneumatic tyres. But they’re also a great insurance against being stranded in the middle of nowhere with a flat tyre. If you want to fit RFTs to your car, make sure that your rims are designed to be used with run-flat tyres, otherwise, you’ll have to replace the rims, too (and that’s when things can quickly become very expensive).
On the other hand, if you blow a run-flat tyre in a remote area and you can’t immediately access a mechanic with the correct replacement RFT, you can fit a conventional tyre instead. Simply make sure that the new tyre has the same size, speed and load rating.
The advantages and disadvantages of run-flat tyres
There seems to be a great divide between people who either love or detest run-flat tyres. Some wonder why they’re even being offered in Australia, where long distances between urban centres have to date made it a necessity to always keep a spare tyre on hand. But with the latest RFTs models being able to travel flat for 150km at up to 80km/h, this argument won’t stand for much longer.
Let’s take a look at a few other pros and cons to run-flat tyres, so you can make up your mind.
The benefits of run-flat tyres
- RFTs allow you to keep driving with a flat and blown tyre – long enough to get you home, to a service station or trusted mechanic.
- RFTs help you maintain control over your vehicle in dangerous situations and eliminate the need to stop the car on the side of busy roads.
- RFTs can help prevent accidents, as they don’t suffer from dangerous sidewall blowouts that impact steering and stability at high speeds.
- Tyre pressure monitoring system. Cars that have RFTs fit by the manufacturer, usually also come packaged with a sophisticated tyre pressure monitoring system that alerts you when a tyre is losing pressure, for example, when it has been punctured.
- You don’t have to carry around a spare tyre and score more cargo space. This also means your car is lighter and more fuel-efficient.
The disadvantages of run-flat tyres
- You have limited options. Because they are unique and not as popular as regular tyres, you have to get a replacement tyre designed for your specific car rim. In some cases, you’ll, therefore, have limited options to choose from.
- RFTs are slightly more expensive than regular pneumatic tyres.
- RFTs can’t be repaired or it would be unsafe to do so, especially if the tire is punctured in the sidewall. If an RFT is punctured, more often than not you’ll have to purchase a new tyre.
Although their advantages certainly speak for themselves, run-flat tyres may not be for everyone. Whether they’re the right choice for you and your car, is a decision you ultimately have to make yourself.
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