Originally Posted by
tFUnK
Yup, I don't doubt that. It could be that the specific butyl tubes you had before were already quite good in quality and performance.
And it seems we should be talking about two independent dimensions here: weight and suppleness. The weight savings is significant (relative % at least) and well documented. The jury may still be out on TPU's suppleness (I gather it may be more supple than butyl but less so than latex?).
You may be right with that ceiling, but I think the best comparison for most people considering these is precisely between higher end butyl and latex (say 80-90g) and TPU (say 35g). Super light butyl/latex seems too fragile and should in theory be significantly more fragile than TPU based on general material properties, so I'd say this sort of weight comparison is fairest. Heavier butyl is of course outclassed by all of them in a performance oriented discussion. TPU and latex cost around the same where I live, 2-3x more than decent performance butyl, and probably 8-10x more than basic butyl.
So many people with good butyl tubes may then wonder which of these is a viable upgrade at a similar cost.
I think it goes something like this:
- If easy install, patching or re-use is required, stick with performance butyl.
- If you do not want to inflate tyres on a daily basis, avoid latex.
- If rolling resistance is a priority, go latex.
- If road feel is important, go latex.
- If weight is paramount at no performance penalty over butyl, go TPU
So TPU gives us a weight advantage with middle of the road performance at the cost of repairability. Butyl is above all practical at the cost of performance or is too fragile on the lightest end of the spectrum. Latex arguably gives us the best all out performance with some air retention and installation inconvenience. There may be more factors, like how rapidly these three materials lose air in various puncture scenarios, which may have a significant impact on safety and recoverability at speed. On that point it seems that it may be TPU>butyl>latex but that's anecdotal at best, and I've read about both 'shredded' and 'very slow air loss' TPU failures. Too many factors here without detailed isolated tests I think. The material definitely seems less prone to tear up from a pin hole, if so, the safety factor could be very interesting on the scales of truth.
I'd pair up latex with an all out aero bike on the flats and put TPUs in a dedicated lightweight climbing bike. That seems like a natural fit.