Tubeless-ness

Wave of the future since 1952-?

Just as with recumbents, the bike industry often has difficulty shifting the paradigm even when a concept like "tubeless" is not exactly revolutionary. Campagnolo and Shimano have found distinct rolling resistance improvements with tubeless compared with the long-standing tubular. Probably the most obvious reason so few UCI races are run tubeless yet is the considerable time spent at speeds above the threshold where rolling resistance is overshadowed by aerodynamic drag. Rolling resistance is predominant below around 25 mph.  And, of course, our fave Eddy Merckx-ism still applies -"the bike is maybe 10% of the equation".

The improvement to off-road bikes is far more dramatic since one such inner tube can weigh as much as the pair of your Dura Ace wheels. Unfortunately, the lack of standards has caused more than a few headaches with the format. Stan Koziatek was the first engineer to employ the essential desirable element of low pressure. His supremely reliable system took the off-road world by storm. More established manufacturers have come around but still tend to require higher pressures to maintain proper function. Very low pressures are not a requirement for road riding, so typical name-brand equipment is often competent. 

The sealant integral with the Stan's system is not always necessary with other rim formats. But the almost incidental effect on flat prevention is often the most attractive aspect. When tires using sealant finally have to be replaced for wear, you will find clots that would have been punctures otherwise, and you never knew.

TPC Blog has just done an excellent primer on this cutting edge tech - from mid last century.