Run-Flat Tires – Are They Worth Having

Have you ever had to change a flat tire on the side of the road?

It was an enormous hassle, wasn’t it?

Changing tires in the middle of nowhere or next to a busy highway as semi-trucks and reckless drivers whiz by at 70 miles an hour is NOT something most drivers easily forget. But, changing a flat on the side of the road is actually the best case scenario. The worst case is a high-speed blowout, which often results in a wreck, an injury, or worse.

For a long time the ever-present risk of a blowout or flat tire was just something that drivers were expected to deal with. You check your tire pressure every month (yea, I’m sure all drivers do that), carry a spare and otherwise hope for the best.

Not exactly comforting, is it? When it comes to potentially fatal accidents, crossing your fingers isn’t very reassuring. Especially when the problem is entirely avoidable.

Enter the run-flat tire:

What Are Run-Flat Tires?

A run-flat tire is exactly what it sounds like a tire that still runs while flat. Actually, to be perfectly accurate, a run-flat tire is supposed to keep your tire from ever going flat in the firstplace.

“Immunity to flat tires and blowouts? where do I signup?!” Sounds like a dream come true!

But, there’s more to these tires than you might imagine at first glance, and that’s where this run-flat tires primer comes in.

As you continue reading we’re going to cover everything you need to know about RFTs to determine whether or not these hazard-proof tires are actually worth relying on.

How Do They Work?

There are two primary categories of run-flat tires being used today –self-supported tires (SST) and auxiliary- supported tires (AST). This may sound like technical jargon to you, but the difference is actually easy to grasp:

Self-Supported Tires are built with a reinforced sidewall. Using a special kind of extremely stiff rubber, SST’s are able to support the weight of your vehicle in the absence of air pressure. These tires literally support themselves, hence the name.

In fact, self-supporting tires are so well-designed that you probably won’t notice a loss of pressure. Since you have a ~100 mile range without air pressure, a tire pressure monitoring system (TPMS) is required so that you know when you’re in need of repairs. Fortunately, all cars manufactured since 2008 are required to include TPMS by default.

Because the only difference between SST’s and standard tires is in the rubber, they can be made to fit on any wheelbase.

Auxiliary-Supported Tires have extra support built into the wheel. The only AST with any kind of market presence is the Michelin PAX Support System, which has a thick polyurethane support ring lining their specially manufactured wheels inside the tire. This prevents your car from resting on the sharp metal of the wheel when you have a flat; instead the polyurethane acts like a cushion and allows you to continue driving, albeit at a slowerpace.

AST’s do not fit on normal wheels; the wheel and the tire together form the support system.

It’s important to know that neither type of run-flat tire is indestructible – Once a loss of air pressure is detected you can drive about 100 miles at 50 miles per hour before your tires will cease to function. Which brings us nicely to the pros and cons of run-flat tires:

The Pros of Driving on Run-Flat Tires

As you might expect, run-flat tires have several noteworthy upsides:

• Safety – The biggest reason to drive on run-flat tires is safety. With normal tires, there is a constant danger that something as small as a nail or screw could cause a flat, or worse, a blowout. Run-flat tires make you completely immune to 99% of tire-related hazards.
• Peace of Mind – 100 miles may not seem like much of a driving range, but it’s infinitely better than zero. You’ll have plenty of time to get to the nearest town and find a mechanic, so you’ll never have to worry about getting stranded in the middle of nowhere with a flat tire.
• No More Spare Tires – Because you’ll never have to change a tire on the side of a busy highway ever again, vehicles equipped with run-flat tires typically don’t even carry a spare. Instead, use that space for other emergency tools and kits. Or carry a spare anyways, if that gives you even more peace of mind.
• Decreased Vehicle Weight – Because you won’t be carrying a spare or the requisite tools for using that spare, your car will be about 100 pounds lighter.
• SST’s Can Be Repaired – Provided the damage is not too severe, self-supporting run-flat tires can be repaired just as easily as normal tires (although you can not use the spray-on sealant). That being said, the closer to maximum driving range you go, the more likely it is that your RFT will need to be replaced.

As you can see, the chief benefit of run-flat tires is safety and peace of mind. Especially if you have a family to worry about, the peace of mind that comes with blowout-immunity is priceless.

Cons of Driving on Run-Flat Tires

Run-flat tires certainly have a strong upside, but there are also several less-than-ideal traits that you should know about before you make a decision to invest in your family’s safety:

• Higher Price – First and foremost, run-flat tires are expensive. Some run-flat tires will cost as much as 3x more than their same-sized standard counterparts. Most of them will run you 1.5x or 2x as much as a standard tire. You’re encouraged to shop around here to see which RFT most easily fits into your budget.
• More Stiffer Ride – While some high-end luxury cars are manufactured and tuned with run-flat tires specifically in mind (eg, BMW, Mini), most are not. Because SST’s use a much stiffer, thicker rubber than standard tires, they are much less forgiving over the bumps and dips of the road. This is a non-issue with ASTs though, since they use the same rubber as standard tires.
• Lower Gas Mileage – Also because of the stiffer rubber used, self-supporting RFTs will yield a lower gas mileage than their more vulnerable counterparts. That being said, the difference is negligible – 1% or 2% decrease in fuel efficiency is the norm.
• Shorter Street-Life – What has kept run-flat tires from seeing more use than they do is the fact that they tend to wear out faster than normal tires, especially if you’re the type of person who likes to speed, or drive more “spirited”. This was a much bigger problem 6 to 8 years ago, and now many brands like Bridgestone incorporate extra cooling features to increase their run-flat tires’ life expectancy. Still, it’s probably safe to expect 30k to 35k miles per tire instead of the normal 40k.
• Less Availability – Last but not least, run-flat tires account for less than 5% of all tires. This means that if you need new tires from a small shop, you may need to have them specially shipped in. This is especially true for Michelin’s PAX tires, as many shops may refuse to work on your vehicle if they don’t have the proper (expensive) equipment available. (Of course, you can easily find RFT’s on Discount Tire where you can either have them installed at one of their shops, or have them shipped directly to your home or shop.)

Final Verdict – Are Run-Flat Tires Worth It?

Now you know everything you need to know about run-flat tires – The good, the badand the ugly.

All that’s left now is to decide whether or not you want to invest in RFTs, andultimately this final decision is up to you.

There is no denying that run-flat tires do have downsides. Costs remain higher dueto the new technology, and the selection is limited for the time being. However, there is no replacement for the peace of mind that self-supporting run-flat tires offer you and your family. If you’ve ever had to change a flat tire, and especially if you’ve ever had a near-death experience due to a blowout, then investing in run-flat tiresmay not even be a question.

Ultimately, the decision comes down to your budget, your driving, and how youpersonally feel about this type of tire. You can find more information and read the reviews on all makes and models of tires by going to our Tire Reviews.