What Are Run Flat Tires?

So you get off work and walk to your car in the parking lot, only to see that one of the tires is flat. Or worse yet, you experience a blowout at highway speed, coming pretty close to losing control before you can safely get off the road and onto the shoulder.

Nobody likes flat tires, as they’re a quick way to ruin your day and can be very dangerous if they happen at 70 mph. What if there was a tire that couldn’t go flat, even if it lost all of its inflation pressure?

The good news is that those tires exist now, and have actually been around for quite a long time. Run-flat tires can’t keep going forever after their loss of air pressure, but they can get you to the nearest tire shop or dealership so that you can address the problem at hand ASAP. On a long trip or even just while doing errands around town, that, by itself, is enough to save you a lot of time and headaches.

Types of Run Flat Tires

Run-flat tires have been around long enough that they are not exactly emerging technology anymore. They’ve been developed and refined, though, and like any innovation there are a few different competing designs. Not surprisingly, each design has its tradeoffs and strong/weak points.

Self-Supporting

A self-supporting tire features an extra-stiff reinforced sidewall that can support the weight of the vehicle even if you hit broken glass or anything else that can cause tire failure and loss of inflation pressure.

Auxiliary Supporting

Some run-flat tires are designed with a support ring of hard rubber or other material inside the tire’s cavity that’s attached to the rim. Even if the tire loses pressure completely, the vehicle’s weight will rest on this wide, hard rubber structure inside the casing that’s attached to the rim.

Self-Sealing

Like the name implies, a self-sealing tire has a urethane, natural rubber or polymer liquid that’s viscous and very sticky inside the air cavity. If you get a puncture that’s less than about a ¼”, this sealant will quickly spread itself through the entire lining of the tire (like a can of Fix-A-Flat does) and seal the puncture from the inside.

Should You Consider Run Flat Tires?

Run-flat tires are becoming more and more prevalent in the tire world, to an extent where some automakers no longer feature a spare tire as standard equipment (which also saves weight and space in the vehicle). But are run-flat tires right for you? Like anything else, they do have pros and cons to think about when you weigh that decision.

Pros

• You won’t find yourself digging through everything in the vehicle to unearth your spare and tire tools, then have to jack up the vehicle and go about changing the tire by the side of the road as traffic goes flying by. That’s more than just an inconvenience – it’s reported that someone is killed while changing a tire every three to four days.
• A tire that fails at highway speed will quickly end up shredded and unrepairable. Worse still, though, a shredded tire means that braking, steering, and handling will become dangerous and can easily lead to loss of control or an accident.
• Most run-flat tires are designed to go up to 50 miles, at speeds up to 50 mph. That can be enough range to safely get you to a tire shop or dealership to get things taken care of after a tire failure.
• Any tire shop or tire tech will tell you that damage to a tire’s sidewall can’t be repaired or patched, and that’s the end of that tire. With more and more vehicles rolling on low-profile tires with “short” sidewalls, this kind of damage is pretty common now. A run-flat tire can usually, but not always, keep going even with an inch-long gash in the sidewall, long enough to get you home or to a tire shop.
• Not having to keep a spare in the vehicle will free up space and give you a little bit of weight savings. Even a “donut” temporary spare weighs about 25 lbs and, when it comes to weight savings, every little bit adds up. Besides, a spare that’s never on the ground or never gets used can end up flat as air migrates out of it over the course of a few years. Additionally, it can actually dry-rot to a point where it wouldn’t be usable at all, and a flat or dry-rotted spare isn’t going to do you any good in an emergency.

Cons

• Thanks to their stiffer sidewalls, run-flat tires often tend to have a harder, less-forgiving ride than conventional tires. The stiffer sidewall can also affect handling and steering response. Consequently, many automakers who fit their vehicles with run-flat tires as original equipment also tune the vehicles’ suspensions (shock absorbers, spring rates, steering components) around that harder ride and do not recommend replacing run-flat tires with conventional tires for those cars.
• Run-flat tires generally can’t be repaired in the case of tire failure. Some run-flats require special tools to repair or even remove them, and not all tire shops are set up for those types of tires.
• Run-flat tires aren’t foolproof. The sidewall of a run-flat tire is designed to support a vehicle that weighs 4000 lbs or so, but that’s not an absolute. Even with their enhanced stiffness, it’s possible for the sidewalls of run-flat tires to buckle. Also, a big piece of debris might destroy even a run-flat tire to the point where it’s not drivable anymore. If that was to happen and you don’t have a spare (of course), you might find yourself calling for roadside assistance or a tow truck.
• Since run-flats still aren’t really common, you might find the selection of run-flat tire models to be a little thin. By the same token, tire shops might not have a great selection of run-flats to choose from, especially if you need a replacement.
• Run-flats tend to be more expensive on the front end, although not always. Keep an eye out for specials, although that extra upfront cost might be worth it for your peace of mind.
• Run-flats usually cannot be repaired and may even be stamped with “DO NOT REPAIR” directly on the sidewall.

What Brands Offer Run-Flat Tires?

The good news is that as run-flat tires become more popular, the number of brands that carry run-flats is on the rise. That includes premium brands like:

• Bridgestone
• Goodyear
• Continental
• Pirelli
• Toyo
• Yokohama
• Firestone
• Kumho
• Hankook