What Is Green Slime for Tires?

How this spare tire in a bottle can save you stress and time.

Benjamin Hunting | 

Sep 12, 2023 | 3 min read

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A tire puncture can ruin your day, especially if your vehicle is like so many modern cars and doesn't come from the factory with a spare tire. Maybe you do have a spare but you blew a tire on a busy stretch of highway where it isn't safe to replace it yourself, meaning you'll have to call and wait for roadside assistance.

Fortunately, there's an alternative to a traditional tire change, and it comes in a bottle.

What Is Green Slime?

Green Slime is a thick, bright green, nontoxic liquid designed to plug a puncture, effectively repairing the tire and making it safe to drive on. It can be used as a patch on holes as large as a quarter inch.

There's an entire line of Green Slime products intended to tackle specific tire repairs. Depending on the formulation, the products can be used as prevention, a quick-fix repair, or both. Some are intended only for off-road or recreational vehicles, while others are suitable for highway driving.

To protect against potential punctures, some Green Slime products can be introduced into an intact tire prior to driving. The rotation of the wheel will cause the Slime to coat the inside of the rubber. If a puncture should occur, escaping air will force the Slime into the hole to seal it and prevent a flat. The company recommends this method only for non-highway use in smaller vehicles such as ATVs or tractors, and claims it will continue to prevent flats and slow leaks for up to two years.

As an on-the-spot repair for a tire that has been punctured or gone flat, Green Slime's emergency-fix formulations can be squeezed into the tire through the valve stem. The product will then seal the puncture and make the tire safe to drive on.

How Green Slime Compares With Other Canned Tire Sealants

It's important to note that Green Slime doesn't inflate a tire as part of the repair. Drivers will either need to keep a portable pump handy to use in conjunction with Green Slime in the event of a flat or buy a full flat tire-repair kit, which includes an inflator that will force both air and Slime into the tire at the same time.

This solution is similar to another popular portable "spare tire in a can" called Fix-a-Flat, a tire sealant packaged inside a can of compressed air that can inflate and seal at the same time without the need for additional tools.

How Green Slime Compares to a Spare Tire

Green Slime does not require wheel removal, making it simpler and faster to use than a traditional spare tire. Green Slime's yellow-label emergency tire sealant, which is the only one approved for highway use, is good for three days of use or 100 miles of driving before the tire must be replaced. In contrast, a full-size spare tire can be driven indefinitely after it has been installed. Green Slime does beat the maximum of 50 to 70 miles of driving generally considered safe for a compact spare.

According to the manufacturer, Green Slime works only on small punctures affecting the tread surface. If damage has been done to the sidewall of the tire, a liquid sealant can't be used.

Benjamin Hunting

Benjamin Hunting is a writer and podcast host who contributes to a number of newspapers, automotive magazines, and online publications. More than a decade into his career, he enjoys keeping the shiny side up during track days and always has one too many classic vehicle projects partially disassembled in his garage at any given time. Remember, if it's not leaking, it's probably empty.