For TPU inner bicycle tires, I found out a little over few months ago. It happened entirely by chance - I read about TPU tires from a comment by Ivan - a fellow cyclist, under a post in one of the cycling groups on Facebook. I had just received my new set of Continental GP 5000 tires, and the post on Facebook was precisely about a topic that is extremely important for every cyclist - tires. :) The colleague had posted a picture of two tiny, thin, green inner tubes and explained that he had recently gotten them and hadn't even tested them yet. Later, another fellow cyclist, Dimitar, strongly recommended these new TPU tires to me in the Facebook chat. He said he had been using them for a year and a half: