Thanks for this video. I just spent several months loving my TPU tubes. I was forced to fit a pair of Vittoria Terreno Dry tires to my new Elite rims. The Michelins I'd bought for them were not even close to fitting the new rims. I'd given up on the Vittorias over a year ago after I installed one and got 7 flats in 200km (with butyl tubes) but I was left with no other option so I put them on the new rims with TPU tubes this time. I rode 2000km without a problem and wondered whether TPU was the secret to transforming the Vittorias from garbage to gold.
I suddenly ended up with 3 flats in one weekend. Each of the TPU tubes that has lasted 2000km went flat, but with the same tire, since the second puncture happened after I swapped front and back and the new tube went onto the back wheel with the less worn tire that had been on the front. With the first tube that failed, no problem. I quickly found the leak when I submerged it in water. The second one then got a slow leak and I had to swap it out on the road and by the next morning the new tube had gone flat too. The second and third ones, though, showed me no bubbles when submerged.
Watching the video, I see I'm not the only one who has found that detecting the leak in a TPU tube is very tricky. I finally did with the other two tubes but they are so slow an tiny. The other thing I liked about the video is that Reginald does the same thing with the indelible marker. I find that to be a slight advantage over butyl since the bright colours of TPU allow you to see a marking where black butyl would not. I still haven't tried patching yet.
One question I have for the OP is why you would say that TPU is cheaper than butyl. I'm finding they can be similar only if I buy Gustavo from AliExpress. Any other brands or sources and I'm looking at far more money than I'd spend on butyl. Is this only because I'm comparing gravel tubes?
