I got a flat tire, kind of a big hole in the inner tube. It was raining a lot so I walked home through the rain and water puddles, and everything got wet.

Now I want to patch the inner tube, but when I inflate the tube, some kind of whiteish liquid is coming out of the hole. I don't know if it is water that got inside (it's not that much anyway).

Do I have to wait until everything dries inside the inner tube (could take a long time) or is this is some kind of lube that comes inside it? If so, is it fair to say I don't have to worry and I can apply the patch with no problem?

  • Welcome to the site! I've cleaned up your question a little, but please don't hesitate to further edit (or even revert) if I've missed the point. Commented Feb 8, 2012 at 19:22
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    "White liquid" sounds like a tube sealant. If it's fairly thick (like Elmer's glue, eg) then it most likely is sealant. Note that you shouldn't have the tube inflated while patching, so I'd get as much air as possible out of the tube, hang it so the liquid drains to the opposite side from the hole, then position the tube on a flat surface with the liquid-filled portion hanging off to patch. Wipe the tube surface clean and then wipe with rubbing alcohol, then allow to dry and patch per kit instructions. Commented Feb 8, 2012 at 20:26

1 Answer 1


There is a type of whitish liquid sealant that some folks (shops, manufacturers) put inside tubes, so that if you have a small puncture it is automatically sealed by the liquid, which solidifies around the tiny puncture.

From what you say, it is not possible to say if that is the case, or if the puncture is larger and water went inside the tube. That would theoretically allow for the powder inside the tube to form a gooey liquid, although I doubt there would be enough amount of water for it to be noticeable.

From my experience, patch glue doesn't mix well with these white sealants, in every tube I patched that already had this liquid the patch got loose soon after, resulting in another flat. So I gave up these sealants forever, unless something new and different appears.

I would suggest, in this case of doubt, that you use the tube's rubber for another stuff (tying something at home ;oP ) and buy a new tube. That is not so expensive, and buying new tubes is integral part of cycling, anyway. Besides, you could cut the old tube to look inside it and get more info which could save you future trouble (Where did this tube come from? Would other new tubes contain the same liquid? Was it sealant or just water? etc.)

Saving old ones for "reuse" too, they are much more useful in the basement than in the landfill.

  • For how it looked like it wasn't sealant, it looked more like the second option you said, the wet powder. But I followed your advice and bough a new tube (it already had two patches).
    – rodrigoq
    Commented Feb 9, 2012 at 16:15

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