Home » Here’s Why The Tire Inflator Kit In Your Trunk Might Not Work On Your Tires

Here’s Why The Tire Inflator Kit In Your Trunk Might Not Work On Your Tires

Do Not Nix Fix A Flat Ts1

Nobody likes a tire puncture, but most people will get one at some point. Whether nails, screws, or something entirely unusual, tires aren’t impervious to sharp objects, and should the two meet, you may get a light on your dashboard that looks like a baseball bat in a punchbowl. Fortunately, there are ways to temporarily rectify a puncture, but what if I told you that the tire inflator kit in your trunk might not work on your factory tires?

In recent years, tire companies have been lining their latest high-end tires with acoustic foam. They go by different brand names — Michelin Acoustic Technology, Pirelli Noise Cancelling System, ContiSilent, the list goes on. However, they’re all more or less the same method of noise attenuation, using sticky-backed foam for marginal noise improvements.

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While you probably won’t notice a difference between foam-lined and regular tires in something like a Jeep Wrangler, you might in a quiet car. That’s why luxury and electric vehicle makers from Tesla to Volvo have been using these foam-lined tires for years. Unfortunately, the appearance of foam-lined tires came right around the time spare tires were disappearing, and there’s a chance that tire mobility kits might not be able to handle small leaks in foam-filled tires.

Pirelli Noise Canceling System tires

It turns out that shooting tire sealant into foam-lined tires in the hopes of stopping leaks might not work so well. As per popular tire sealant brand Slime:


We do not recommend installing Slime sealant into quiet tires. The tread area of a quiet tire is coated with a layer of foam. If the sealant is installed, it will be instantly absorbed into the foam, rendering it unable to reach and treat the puncture. The sealant will also likely result in tire vibrations. Additionally, there is no way to remove the sealant from the foam and the tire will likely need to be replaced.

Wow, the foam used to keep tires quiet can act like a giant sponge. Who’d have seen this coming? Oh, and guess what: Fix-A-Flat’s website includes the same blurb verbatim. Making things more puzzling is the fact that most car manufacturers include some form of tire sealant in the trunk of cars without spare tires, meaning that the equipment provided by the manufacturer for emergency roadside tire repair might not be fit for the tires that are on the car. A noteworthy example is Tesla, a brand happy to sell you a replacement sealant-reliant tire inflator kit for cars with foam-lined tires.

Thankfully, there is one good old-fashioned method of tire repair that will get cars with foam-lined tires back on the road in a jiffy — tire plugs. These little pieces of rubber take some muscle to install, but so long as they aren’t in a sidewall or within half an inch of the edge of the tread, they usually last the life of the tire, require no dismounting, and require no re-balancing.

Tire plug kits are cheap, often priced at $20 or less, and they’re remarkably simple to use. Just pull the cause of the puncture out of the tread, ream out the hole with the included reaming tool, push a plug into place using the included plug tool, swiftly pull the tool out, and trim the excess rubber with a razor blade before re-inflating the tire.

It sucks that some automakers aren’t equipping their cars properly for roadside emergencies, instead hoping that a can of flat-fixer will play nicely with foam-lined OEM-spec tires. However, it doesn’t take much to be prepared. A jack, a lug wrench, and a plug kit could save you a lot of misery out on the road.


(Photo credits: Continental, Fix-A-Flat, Pirelli)

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1 month ago

working as a tire tech at a Walmart tire shop (the source of my username here on the Autopian) it infuriates me to no end seeing a late model car show up to our shop on the back of a rollback with an absolutely destroyed tire and find out that instead of a donut or a collapsible space saver spare, it has one of those stupid “Mobility Kits”. fat lot of good one of those does when the tire has chunks missing out of the sidewall, has blown out so violently that the only parts of the tire left are the beads stuck to the rim, or the rim is damaged in some fashion be it pothole damage that bends the rim to where it won’t hold air (regardless if its a steel or alloy rim), cracking on aluminum alloy rims, or if the rim is completely destroyed by pothole or collision (ive seen aluminum rims that are split right in half rendering them as scrap metal)

1 month ago

Another reason is that I’ve heard of a lot of ‘space savers’ that require inflation with the supplied compressor are breaking their beads. Once that happens there’s no easy way of doing anything about it beside the road.

1 month ago

Would never use such tires as those foam things. As for Fix-a-Flat, I’ve used it dozens of times to good effect. I used to frequent job sites where lazy and clumsy contractors would spill and leave screws, nails, etc. onto gravel lots, so I got lots of slow leak punctures. Obviously, they don’t work for slashes, but it’s been a long time since I pissed someone off who sought out that wuss way of retribution.

I tried those outside plug things (the inside plugs work awesome, but obviously aren’t so readily DIY) and could never get them to work. No matter how much I reamed out the hole (once, I even broke out a larger file to try enlarging the hole beyond the reamer’s size), every time I jammed the plugs in, the insertion tool would tear the plug in half while maybe getting partially into the tire, though not far enough, like a fig wasp that sadly failed at its life mission. Good at distributing the adhesive all over my hands, though.

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