How run flat tires work
While we’d all like to think we’re invincible on the road, deep down we know better. And nothing deflates the ego faster than a flat tire. If you’ve been there, and chances are you have, you know the feeling: that sudden dip in the pit of your stomach as you realize that you need to pull over in rush-hour traffic, and can’t quite remember where you left your jack.
Some choice words and a once-clean pair of pants later, you’re back on the road, but your mood is in the gutter, you’ve lost valuable time, and possibly risked your safety while becoming your own one-person pit crew. Wish there was a way to avoid the hassle of a flat tire?
There is: enter the run-flat tire. This is a broad term that encompasses a range of tire technologies designed to keep you on the road and out of harm’s way, even after suffering a complete loss of air pressure. Of course, while run-flat tires may seem like superheroes wrapped in silicone, they aren’t invincible. In order to fully understand run-flat technology, it’s important to weigh the pros and cons of driving with it.
Here are a few things you should know before equipping your car with run-flats and running over a box of nails:
What do run-flat tires do?
Simply put, run-flats keep you driving after a flat. Boasting safety first and foremost, run-flat technology allows you to continue driving for a certain distance at adequate speed after a continuous leak or puncture, and also prevents having to get underneath your vehicle on the side of the road as traffic whips by.
How do run-flat tires work?
The vast majority of run-flat tires available today are what's known as "self-supporting" run-flats. These tires use a thicker, and therefore stronger, sidewall that’s able to safely carry the weight of a vehicle (generally up to 50 miles at up to 50 MPH) so you can get where you need to be. A number of popular brands provide run-flat options for their most popular tires, which are easily identified by the seemingly random abbreviations attached to them -- Bridgestone and Firestone call their technology RFT (Run-Flat Tire); Dunlop calls it DSST (Dunlop Self-Supporting Technology); Goodyear goes with ROF (RunOnFlat) or EMT (Extended Mobility Technology) – these are all examples of self-supporting run-flat tires.
Now, since the main purpose of a run-flat is to eliminate the ugly, let’s take a look at the good and bad aspects of the technology.
Benefits of Run Flat Tires
Mobility after a flat
This is the obvious advantage. When pesky nails or other sharp objects puncture your tire, you can just keep open driving, so you don’t have to stop in an unknown area or dangerous stretch along the road. Which leads us to the next advantage...
Aside from convenience, run-flats provide immeasurable safety because they allow you to stay mobile, without the sudden and sometimes violent changes in maneuverability that can happen when you suddenly lose air pressure.
Less weight and more space
Since you don’t have to change a run-flat right away, you can do away with that heavy, space-consuming spare—though we recommend using caution before tossing that donut by the wayside.
Run-flats: The Bad
Compared to your everyday tire, run-flats on average cost one-third more—and you can’t pair them with traditional tires, either. You’ll also be replacing run-flats more often: in a recent study, J.D. Power and Associates discovered that drivers who rely on run-flats replace their tires an average of 6,000 miles faster than standard tires, and that vehicles riding on run-flats are twice as likely to need to replace their tires after a flat or blow out—because after they do their job, run-flats can’t be repaired.
Reduced fuel economy
All that technology is heavy, and weightier run-flats can reduce your fuel economy by 1-2%.
Run flats require specific configuration standards, and it can be hard to find exactly what you need. That said, we have a pretty strong selection of run-flats, so be sure to check out TireBuyer.com if you need a set.
Run-flats vs. traditional tires
While run-flats offer obvious benefits, there has been some backlash recently. Drivers have cited faster and uneven wear and a stiffer ride, as well as the aforementioned replacement bills and limited replacement choices when compared to regular tires. And then there’s this: though many upscale and sports vehicles come equipped with run-flat technology, drivers have cited a noticeable decrease in overall ride quality. Automakers counter this claim by stating that the free weight from eliminating a spare produces better handling and improved economy, and that OE applications equipped with run-flats are specifically tuned to counter the stiffer sidewalls. That said, while you may not have to deal with a roadside tire change, certain disadvantages can certainly flatten your mood.
Bottom line: Is run-flat technology worth it?
Despite the downsides, many manufacturers and drivers alike say the safety and convenience of having run-flats outweighs the cost and replacement woes. And the fact is, as technology increases, so does run-flat usability. Most major manufacturers attach run-flat technology to their leading tires, which is a reaffirming testament to their trust in them, as well as the public’s acceptance. Ultimately, of course, it’s up to you and your preferences.
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