Can Fix-A-Flat Safely Fix Your Lawn Mower Tire? Here's What You Need To Know

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Checking the air pressure in your lawn mower tires is one of those lawn mower maintenance tasks everyone forgets, but doing so may alert you to a slow puncture so you can act before it becomes a full-on flat. With either problem, you'll want as quick and easy a repair as possible, and a can of Fix-a-Flat aerosol seems like the ideal solution. If you can use it to seal and inflate car and truck tires, then it should work fine for lawn mower tires — you just put less gunk in there, right?

Well, actually, no. On its website, Fix-a-Flat specifically states that the product is for "automotive highway tires." It is not for use on ATVs, lawn mowers (or lawn tractors), golf carts, et cetera. However, a couple of videos on YouTube suggest it works fine, with the channel How-to and Reviews having run their lawn tractor the whole summer (although it did lose a few pounds of pressure, one reason why your lawn mower might cut unevenly).

So is Fix-a-Flat really not safe? There are a few potential issues, as reported by users on the forum LawnSite. First, you may not be able to drive a lawn mower fast enough for the product to work properly. So it won't seal a hole. It also causes a horrible, sticky mess, so if you eventually replace the tire, it's a nightmare to clean up, and a tire shop will likely charge extra. There are also reports that it can rust the tire rim.

There are dozens of different patch or plug repair kits for lawn mower tires, but none of them are as quick or simple as Fix-a-Flat, and some cost two or three times as much. However, there is a product called Slime Tire and Tube Sealant available from Amazon for about $14.99. It works in a very similar way to Fix-a-Flat, except it is intended for non-highway tires, like those found on lawn mowers. What's more, it is eco-friendly, non-toxic, and non-corrosive, so it won't rust your rims.

There is another alternative hack you could try that can banish flat tires from wheelbarrows and has been used successfully on lawn mower tires (per Mother Earth News). It could even work for leaking valves, larger holes, or splits in sidewalls that neither Fix-a-Flat nor Slime can handle. The idea is to fill the tires with expanding builder's foam instead of air. It takes a few days to harden, and it may need topping up, but once the tire is full of hardened foam, you should never have problems with punctures again.

There are drawbacks. The tire will be heavier than if filled by air, so steering will likely require more effort. Also, the foam doesn't add any strength to the tire, so it's not recommended for those that are already well worn. In that case, replacement is the best option.