First thought is something is up with that rim, either the rim tape is bad in an area or you have a burr on the inside somewhere. The lightweight tubolito works it's way somewhere it shouldn't, and/or tears on a burr because it's so thin

Thanks for replying. Makes sense & I will re-tape. Still, I ran both tubes under water for bubbles/air escaping from rim-induces flat. Nothing, as in, no puncture/s. Is this just a TPU thing?

Oh, if there's no hole in the tube, it might just be TPU losing air faster, or you can double check the valve core to make sure it's not leaking there

Yup, REALLY wired. Can't figure it out!

Have you checked the valve core? The first Tubolito I got had a loose valve core and therefore was leaking air.

Yeah, no air coming out. I'm thinking the rim tape is weak at some spot(s) & somehow forcing air out. Again, this is the 2nd tube I have tried.

How quickly is it going flat? Minutes/hours/days?

I'd say a day.

I tried really hard to like the Revoloop inners (also TPU) - and I kept loosing air too. I think its the weak joint where they glue in the inflator tube at a guess.

I gave up and went tubeless - tyres still holding weeks after filling. Not going back.

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Regards, Richard

Thanks for responding.

Did you have a puncture with the TPUs?

Nope, swapped out the old tubes for these, first one went soft overnight, refitted, again went soft - this was even before taking for ride.

Replaced for another, one ride, didn't puncture - but next day was soft again. Too much hassle.

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Regards, Richard

Those tubes have a very, very narrow niche. They are not as cheap and easy to use as butyl. Do not perform as well as latex, and are even more expensive.

The only use-case I can see is race day spare tube given its very low volume when rolled up.

Not even everyday spare tube (for me). I like to carry butyl so I can just toss-and-forget tubes to people on the side of the road without worrying about tossing them $35.

Well that's interesting!

I've used TPU for 2-3 years (yes, even when they were really expensive) because they held air much longer than latex. I have seen them lose air quickly and not seem to have a hole. But with very careful inspection I've found them. The difficulty is getting enough air in the tube to show the leak without blowing it completely out of shape.

On narrow tires (23s) I've had to be much more careful on installing them, as I seem to pinch them more than on wider (28s) tires. Once I have them properly installed, I don't have a problem. I have found that patching them is easy, although it's not a quick as a butyl tire.

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Not a coach. Not a FOP Tri/swimmer/biker/runner. Barely a MOP AGer.
But I'm learning and making progress.

Thanks for replying.

So like I had mentioned, I did the water/bubble test to check for punctures but didn't find any. What did you "careful inspection" entail in finding the hole(s)? I ordered the patch kit.

I went *much* slower checking the tire than with a latex or butyl, including the valve area. If you have extensions, you also want to go very slowly there. As I said, the hardest part is getting enough air without ruining the tube.

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Not a coach. Not a FOP Tri/swimmer/biker/runner. Barely a MOP AGer.
But I'm learning and making progress.

The only use-case I can see is race day spare tube given its very low volume when rolled up.


Same.

Still not doing that for the other reasons you state - to sensitive to just toss in a saddle bag or stuff in a back pocket. Because when you NEED at replacement tube, and I'm typically carrying only one CO2, I REALLY need it to work! Butyl is way more durable and reliable.

Been running latex tubes for years and I don't really see or understand the advantages of these new higher tech inner tubes.

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Steve Fleck @stevefleck | Blog

for a while I really wanted to like Tubolitos but they were hit or miss wrt to leakiness and I just got fed up with installing a new tube, just to find out that it is leaky again. Maybe they have improved their QC in the meantime - but my experience matches with what you seem to observe....