cycle tramp wrote:As for the 559 size dying completely.. well it was around in the 1950's and it's still around now.... again, it's just been given new life by dirt jumping, and could well be given further life by electric bikes - where any pre-supposed marginal performance losses are of set by a stronger wheel.
A tyre size does not have to die completely to be deadly dull and a terrible choice for touring, where the inability to buy a decent replacement at any nearby shop - like any motorist might - can blow a gaping hole in your annual holiday.
I honestly thought, and hoped, that 559 would continue to be a standard size for MTB wheels for shorter riders at least, even after 29ers proved how much more easily a bigger wheel rolls. The difference is especially marked on soft ground, where resistance can vary by as much as the inverse square of diameter - or at best simply by the inverse. 29/26 = 1.115, squared = 1.244. I think you'll agree that an increase in drag of at least 12% up to 24% is a bit more than marginal!
Size makes nowhere near as much difference on the road, but that's not what MTBs are bought for. So when some bright spark realised they could sell every existing MTBer a brand new bike by resurrecting 650B (ironically the size that Geoff Apps, a British pre-MTB pioneer had used) the writing was on the wall for 559 as a do-anything tyre size. Still, I was amazed that it took only two seasons for it to disappear from all but the cheapest new bikes.
Dirt jumping isn't about going places, so rolling drag hardly matters there. Nor for electric bikes - a motor forgives a multitude of mechanical sins! So don't expect anything nice to pedal yourself for long distances from either of those trends!
I'm hopeful that 650B (ISO 584) may become the new do-anything 26in size, replacing 559 and 571 (590 already being obsolete). But even if that happens I'll be sad that 559 didn't remain in that role, as being appreciably smaller it was more useful to designers of bikes for small people and folders etc.