Foss tubes

So, I just had my first problem with foss tubes.
A few nights ago I was woken by a sudden “wham” sound and hissing noise. The 36" foss tube had suddenly blown.
At first I thought it was the valve, because the that’s where the air was coming out from. But taking it apart I found this:

The extra layer of the rimtape ends have created a tension point. I really like the foss tubes; they may be puncture resistant, but they are not durable, it seems.

Today I fitted a 29" rubber tube on my 36’er; and a pain it was! But it rides well. I got 24 km/t on a short stretch, so it’s not holding me back. I’m looking forward to see how it holds up, as it only weights a little more than my foss tube.

I have a Foss tube on a 29er. It’s been completely issue free, till I replaced the tyre. I replaced the tyre, inflated, then had a small slow leak. So I repaired the leak. All ok. (I left it overnight to be sure). I put the tyre on again, reassembled the uni and then discovered I have a leak again. So annoying. I havent further repaired it as I find putting this tyre on and off a big effort

I have now patched it a second time… so far, so good. I think it was my method for putting the tyre back on. My tyre levers were pinching the Foss tube…

Been there too :wink:

I think your Foss tube hole will be easy to fix. So, I suggest it’s worth fixing,

Pics of mine.

You can’t use normal bike patches to fix foss tube (I read), and I doubt I can get the patch on the corner of the valve. But I’m gonna try.

Yeah ok, not an easy spot. But worth a try.

I have already done it, the thing is I won’t be installing it anytime soon. Unless my rubber tube, I just installed, fail.

1 Like has the Foss tube patches. They are very light so the postage isn’t too much.

Also, I discovered that the Foss tubes are directional. Make sure you put it back on the correct way: or

However, I’d guess that your tube was a little weak right at that seam at the valve and the pumping wiggled it a bit and it broke through there. I’m rarely successful patching near the valve stem. I use a new tube if I get a leak there. Other places can be patched, but the valve stem area is really troublesome.

Hmmm… i just read the pdf, perhaps I stuffed up in the installation… didnt massage it at 0.5psi and didn’t check where the seam is on the tube…

And from more reading… you can repair a Foss tube with a cigarette lighter?

From an Ebay description

Item description

“Explosion Proof: The tube is made out of a highly polymerized un-vulcanized rubber composite. When punctured, the material forms an air-tight seal around the nail or glass, dramatically slowing or even stopping the leak, giving riders extra time to react. Ultralight Weight: With a density of only 0.88 g/cc,the tube is 30% lighter than standard tubes which can have densities up to 1.3 g/cc. Easily repairable: In the event of a puncture the tube can be easily sealed with a simple cigarette lighter or Foss glue less patch. Removable valve core: Valve extensions can be used. Environmentally Friendly: Made from modified thermoplastic elastomer compounds (TPE), it can be recycled thus minimizing waste and protecting the environment. Free rim tape: Comes with a free rim tape. Size: 26x1.35 - 1.75 Valve: Presta.”

Not sure whether or not it’s the rim tape doing it but I had two Foss tubes fail in that same spot on my 36er. After the second one failed I gave up and put a 29er tube in instead.

Good to know I’m not the only one. My fix is holding; I guess I will bring it as a lightweight spare.

They often fail at the valve, where you can’t do anything to fix them. Often it’s because when you inflate them, and wiggle the valve, it puts stress on it. And as they leak more than regular tubes, you do inflate them more often.
Only the clear ones can be patched with fire/heat, if I remember correctly. And even then, it’s not 100% guaranteed success.
For a 36", there are good butyl 29" alternatives out there. If you really want super light, Tubolito tubes are an option.

Vee Tire makes 36 inch tubes, but they are presta. Easy to get a presta adapter though.

That is what I am using on my 36 after the Foss tube got a flat. I never looked for where the leak was. I bet it will be in the same area.

Mine (foss) weren’t holding pressure from week to week.

1 Like

Hmm, I’ll look at it. But no way am I buy from USA.

Understand. Might be hard to find in stock also.

I can’t find any available for sale in EU. I have to rely on unicycle DE.