Tires & Tubes Fat tyres puncture repair


New member
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2:53 AM
May 31, 2023
Hi, I’m wondering what is best to carry with me in respect of punctures for 20x4” tyres?

Does anyone make a puncture-proof tyre in this size? I used to run Hutchinson Kevlar tyres on my road bike and literally never had a puncture.
Fat tires have no puncture-resistant options worthy of the name. The reason is simple: Think of how heavy a thorn-resistant tube is. Now scale it up so its diameter is gigantic like a fat tire. Same deal with the tire itself. They'd be super heavy. You can purchase Tannus Armour but having done many installs of it, I'll recommend you stay away from it. Too many negatives.

With that said, I have done rather a lot of daily riding on fat tires and I've got what I'd call the secret formula for flat prevention. Secret in 2020 at least. In 2023 its pretty common:

Use FlatOut Sportsman Formula. It will seal holes up to 1/2" in size and never hardens. Has a lifespan of 10 years so thats effectively the life of the tube. It works as a tubeless sealant as well. Running tubeless with a full cargo load on my Surly Big Fat Dummy, I hit a strip of 6 discarded roofing nails and so had 6 punctures, closely spaced, at the right side of my tire. tread. Fortunately I also had an electric air pump as well. I refilled, spun the tire, rode about a block and stopped; refilled again and did so three more times, with air loss being steadily less with each fill. The sealant repaired the damage and I rode home. That was a couple of years ago and the same tire is still on the bike, although it is about worn out now.

Here is an excellent fat tire flat test. Note the Tannus vs. Flatout performance.

And here is the tool kit to run around with. Heavy emphasis on the patch kit.

You really, REALLY need to learn to patch tubes if you don't know how to already. Consider the cost of one tube, and then look at this pic below. 5 patches visible and it got to 7 before #8 was on a seam that could not be patched. Patches are stronger than the original tube material and cold-vulcanize to the surface, so they may as well be welded on.

Thanks very much for taking the time to provide such a detailed and useful reply.