Many top end road bikes have gone to 1 1/8" top and 1 1/2" bottom headset bearings. I wonder if/when any tandem frame designs will start to move in this direction? Could this be a good standard for tandem frames to head toward? Would accomplish increased front end stability and common hardware in new frames and fork designs, though its always painful in many aspects to move to new designs.
I suspect if the tandem market was filled with consumers who bought the latest and greatest uber-light bike offering from (fill in the blank) every year and tossed last year's model aside, then this latest fad in bicycle technology would quickly be adopted by tandem builders.
However, the problem with these "innovations" is that they don't follow any standards and leave owners stuck with proprietary equipment that may or may not continue to be supported in the future. Check out the history of the bottom bracket / crank interface designs over the past 10 years and you'll find all kinds of different generations of "great innovations" in designs that are now obsolete. Hey, how about some of those really cool proprietary seatposts that also squeeze out aftermarket options and alternatives? Will they be adopted too? Let's hope not. After all, it was this highly integrated, proprietary approach to component development that led to buyers having their choice of Shimano, Shimano, Shimano, or Shimano on all but custom spec bikes.
As for headsets, they too have had hit a few evolutionary bumps in the road and a few years back I posted something on the history of headsets which you can find here. However, for the here and now is a a photo line up of the four major, conventional headset sizes:
Going from left to right, the first (black) is the 1" headset, used on almost all road bikes and even tandems well into the 80's. In the late 80's / early 90's the next two size headsets struggled for world domination: the 1.125" (1 1/8" - blue) and the 1.25" (1 1/4" - red). Santana jumped on the 1.25" headset and has stuck with that standard ever since. Cannondale briefly flirted with it, but quickly opted to go with what turned out to be the most common (and more than adequate) size, the 1.125". Trek's first attempt at tandems used the 1.25" Evolution headset, as did a few of the very first short-lived Meridian and perhaps even a few Longbike tandems. With the exception of Santana and perhaps BikeFriday, I believe most tandem builders use the 1.125" headset as their standard and consumers have a wide range of headset, stem, and fork options because of that standardization. Good luck finding a wide selection of 1.25" stems and forks, which is why the De-volution headsets have a market, e.g., a 1.25" headset that accommodates a 1.125" fork steerer. The last one (gold) is the One-Point-Five (1.5") headset: a beast of a thing created to deal with the abuse that downhill and freeride bikes take which necessitated a larger steerer tube, fork steerers, and yada, yada, yada. Of course, if you're not a 180lb gravity racer bombing down a ski-slope in the summer at "break-your-neck" speeds, do you really need a headset that rivals the size of headsets that are as big as the ones used on early motocross (e.g., Honda CR125 Elsinore) bikes years ago?
These innovations are designed to sell new bikes (period). In most cases they don't solve problems, they create problems. However, if someone is a slave to bicycle fashion and must have the latest and lightest bike offered (or one that can be dropped from a cliff yet still ride away) because, well.... it's the latest and greatest, then you're all set. And, with any luck, you'll have grown tired of that bike before replacement parts are no longer available even from the 3rd tier suppliers as the OEM will have quickly moved on to the next latest and greatest design.
I don't knock the industry for pushing the envelope on new developments to drive sales and feed consumer demand, it's their job. And, in some cases there truly are some new developments that truly do bring new technology to the market. But, as consumers, we do need to keep our wits about us now and again.