Run-Flat Tires: What They're For And Why You Buy Them (Besides Destroying Your BMW’s Ride Quality)
Not to ruin your day or anything, but you should know that there’s a very good chance that you’ll have a flat tire at some point in your life. Even if you drive like a saint and carefully avoid every pothole in the road, tires just fail sometimes. For obvious reasons, that can be annoying and unsafe, but what if we told you that there might be a way around some of the hassle? That’s the draw behind run-flat tires. In theory, at least.
For several decades now, they have been the go-to for auto manufacturers and drivers looking for peace of mind. Using a variety of technologies, tire makers are able to build tires for everyday vehicles that can continue running for dozens of miles after being punctured or losing air pressure.
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Whether you’ve heard of them or not, run-flat tires are a thing and will continue to be a thing for years to come. The Guides & Gear editors have had a flat tire or two in their lives, and are here to tell you that run-flat tires can be a great thing, but they don’t come without trade-offs. Let’s take a closer look at what they are and how they work.
What Are Run-Flat Tires?
Run-flat tires are, as they sound, capable of supporting the weight of a vehicle for a short period of time with no air in the event of tire damage or a blowout. Many run-flat tires offer around 100 miles of functional range to give the driver enough time to find a repair shop. In the world of run-flat tires, self-supporting tires are the most common.
They feature stiffer, reinforced sidewalls, which can support the vehicle while suffering from low or zero air pressure. Some tires feature self-sealing technology, which uses a material inside the tire to fill holes in the exterior, which aren’t technically run-flat tires but are generally lumped in with the category for simplicity.
Who Invented Run-Flat Tires?
The story of run-flat tires takes us back to the mid-1930s when Michelin introduced a tire that could continue rolling after a puncture thanks to a foam lining. It wasn’t actually developed for automobiles, but rather for use on commuter trains and trolleys, and was then sold for military use on armored vehicles.
The tires were effective but too expensive for use on everyday vehicles at the time. In the late 1950s, Goodyear and Chrysler partnered to offer a run-flat tire, and in the early 1970s, Dunlop launched a run-flat tire for the Rover P6.
In terms of run-flat tires, as we know them today, Michelin developed a model for the Lincoln Continental in 1996, and notes that its 25-year history developing zero-pressure tires has given drivers the safety and security of traveling without fear of being stranded from a blowout. Its tire lineup includes self-supporting all-season performance tires, as well as run-flat tires for OEM applications, such as the BMW 3 Series or the Mini Cooper S.
How Have Run-Flat Tires Evolved Throughout the Years?
Like many still do today, the original run-flat tires used a self-supporting structure. This could include a foam lining, stiffened sidewalls, or other reinforcement inside the tire. Since then, run-flat tires have evolved to include self-sealing tires and other reinforced tire types.
Self-sealing tires typically feature a secondary lining inside, which can seal a small puncture hole caused by a nail or screw. Some versions of run-flat tires today feature a support system inside the tire that is capable of carrying the vehicle’s weight, and at high speeds. These tires are the standard run-flat option for military, police, and other vehicles.
As Michelin explains today, the main enemy of run-flat tires is heat. As tires roll down the road, they generate heat, both from the friction of rubber on pavement and from the materials inside the tire. As technology has advanced, run-flat tires have evolved with materials to both dissipate heat and to avoid generating it in the first place.
Why Do So Many People Think Run-Flat Tires Are Bad?
Run-flat tires have gotten a poor reputation for comfort and performance, which for many years now, has been fairly earned. Run-flat tires’ sidewalls are stiffer than traditional tires to support the weight of the vehicle with no air pressure, so they don’t flex and offer the same grip that regular tires do.
They can negatively impact ride quality and can bring a harsher experience to many vehicles. People also knock them for being more expensive and harder to find than standard tires, which is deserved, too. While those things can be true, they don’t tell the whole story.
When we broached these subjects with Russell Shepherd, Michelin’s technical communications director, he told Guides & Gear that the company focuses on developing zero-pressure tires (ZP) that resist heat and that are capable of withstanding high speeds, both when inflated and when suffering a loss of pressure. Likewise, Michelin has developed run-flat all-season tires for high-performance applications, such as the Chevy Corvette, and notes that the company has continued developing and iterating special rubber compounds and technologies to improve ride quality and performance while retaining the ability to run with zero pressure.
That’s not to say they’re perfect, it’s still an evolving process. But the run-flat tires of today are far better than the run-flat tires of 10 years ago.
What Are Some Available Run-Flat Tire Options?
Like us, we’re sure you want some options, so here’s a quick rundown of manufacturers that offer run-flat tires in the common types of tire compounds.
High-performance run-flat applications exist, such as this one for the Lexus LC500.
FAQs About Run-Flat Tires
You’ve got questions, The Drive has answers!
Q: How long do run-flat tires last?
A: Run-flat tires are available that last just as long as, if not longer than, traditional tires. The Bridgestone DriveGuard comes with a five-year/60,000-mile warranty, which matches some of the best tires of any type.
Q: How much more expensive are run-flat tires?
A: Run-flat tires are consistently more expensive than comparable standard models. In general, run-flats cost between $25 and $75 more per tire. It’s also important to remember that run-flat tires are usually not able to be repaired and sometimes must be replaced in pairs, so the costs to run and maintain run-flat tires can be greater over time.
Q: Can I buy run-flat winter tires or performance tires?
A: Absolutely. Tire makers offer run-flat versions of the most popular winter tires, and many major tire manufacturers make dedicated performance run-flat tires.
Q: Can I replace run-flat tires with regular tires?
A: Sure. It’s completely fine to replace run-flat tires with regular tires, as long as the replacement tires meet the manufacturer’s recommended standards. You will need to replace all four tires at once to avoid mixing tire types.
Run-Flat Tire Fun Facts
You know you want more run-flat tire facts!
- Though you won’t be fitting its tires to your daily driver anytime soon, Lego is one of the most prolific tire producers in the world. The toy company makes over 300 million mini tires each year, all of which happen to be run-flat.
- Run-flat tires make it possible to eliminate the spare tire, which reduces weight and space requirements in new vehicles.
- Some heavy equipment runs on solid tires, which don’t use air at all. These tires are heavy and are only really used in commercial and industrial applications.
- Run-flat tires can still experience blowouts and damage, just like any other tire. In some cases, the damage can be great enough to overcome the tire’s weight support capabilities, rendering them unusable.
- Run-flat tires aren’t available for motorcycles yet, because the stiff sidewall and heavier construction make it difficult to generate traction and operate safely.
Sometimes it’s best to let actual tire companies describe run-flat tires. Here’s Bridgestone’s take.
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