Country Lore: Avoid Flat Lawn Mower Tires

Lawn mower tires won't hold air? Fill them with foam and they'll stay firm forever.

| April/May 2009

lawn mower tires

Foam-filled lawn mower tires resist punctures and stay inflated forever.


I grew tired of having to air up the tires on my riding mower each time I used it. I tried “Slime” tire sealant, but with all the holes they had in them, the tires still went flat.

Then I had a hairbrained idea: inject all four lawn mower tires with foam. It worked great.

Here’s how to do it:

  1. Purchase at least two cans of minimal expanding rigid foam.
  2. Jack up the mower.
  3. Drill a hole just large enough for the canned foam’s spray tube. I turned the tire/wheel assembly so the valve stem was at the top, and then drilled the hole in the center tread of the tire itself. I removed the valve stem insert as well.
  4. Insert the tube into the tire and spray the foam into the tire. Watch for foam to start exiting the valve stem area; the foam will just have about filled the tire by that time. This also allows any air in the tire to exit. Replace the valve stem insert and cap to keep the foam from exiting.
  5. Keep filling the tire. Do this until the foam starts to exit the hole you drilled.
  6. Allow the foam-filled tire to remain jacked up for a few days to make sure the foam has cured.

After a couple of uses, the tire softened up some and started to get a flat spot when it sat for a few days. To remedy that, I added more foam.

Even if I have to do this a few times, eventually I think the foam will be compressed to a certain point where it will not compress anymore.

If you don’t want to do all this, there are tire shops that will fill tires for you.

1/2/2016 9:16:57 AM

Try stans no tubes... which is just a product you put in your tire. Not anywhere close to the green slime stuff that doesn't work. Check out the attached video.

9/12/2014 2:05:11 AM

Trying to fix my flat tire prob on my rear tractor tire. 1980 somthing craftsman gt18 with the earlier b&s.I Just filled up my tire with water then put bar and chain oil mixed with dish soap to top it off.. super foamy, rust preventer? heck I dont know ...Im just tired of filling em with air every 2days.I just hope the next thread I read doesnt say "DO NOT FILL YOUR GARDEN TRACTOR TIRES WITH BAR AND CHAIN OIL AND DISH SOAP!!!QUICK AND SUDDEN DEATH MAY OCCUR.."what do you think about the enviromental side? How the heck do I submit my posts withouyt having to type some secrect code into an advertiseme4nt?

4/7/2014 6:55:34 AM

I used foam in my lawn mower tire. Just an old snapper type with 4" tire. I used the regular expanding foam for insulation. I let it sit for 18 hrs after I filled it up. Used it for 30 mins and noticed that the tire looked like it was going flat. I think that it was just the weight compacting the foam. I might have to come back in a few weeks and add some more just to fill it back up. So far so good.

5/24/2013 8:18:04 PM

Old post but here is some feed back.  The stuff in the can is usualy a low density foam, It might not work well for anything other than a wheel barrel.  The stuff in the can also requires moisture for it to cure properly.  If you pour in some water into the tire and then put in the foam you will end up with a more solid foam.  As for me, I bought a 1/2 gallon of two part 8# foam.  I will tell you how this works out.

2/17/2010 12:22:49 PM

My tires had dry rotted, and would not seal. So I used two cans of "Great Stuff" per back tire and one can per front. The trick for me was simply breaking the bead, filling in under the bead, and while the tire was laying flat let it push the bead back up. You need to spin the tire a bit when you pour the foam so that it spreads evenly. But, it tends to even out on its own either way as long as the tires are laying flat. Its $8 a back tire, $4 a front. Cheaper than tubes or replacements.

michael _2
4/24/2009 4:52:05 PM

Just fill them with water cant get any cheaper than that and most wholes are to small for the water to come through. I have used this in my mower tire for over two years I have to rewater them once a year but they wouldnt hold air at all when I started I us air to boost the pressure the las 2inchs in the tire.

4/22/2009 2:26:56 PM

Places like Harbor Freight and the bigger hardware and feed stores sell *solid* tires that never go flat. They make them in many sizes to fit small mowers/tractors. They usually cost less than buying the foam to do it yourself.

richard dean
4/22/2009 1:25:06 PM

what type of foam ??? the spray kind as in insulation called aahhhh"greatstuff" ???

3/31/2009 6:00:30 AM

Certainly, installing a tube can repair the flat. In my case, tubes are punctured soon as well. The foam filled tires were the best option for me. For sure, weigh all your options, prior to implementing a solution.

3/23/2009 7:32:34 PM

Why not just put a tube in the tire.. I did and no more flats.

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