I got a bit obsessed with inflation products recently, and went through a whole series of articles related to pumps, and especially pump heads. At the time, I was a bit torn between my modified KCNC head, my Silca Hiro v.1 head, and the original Hirame head. Now, for most uses, the much simpler Silca 17-4 Presta Head is ideal. The 17-4 head, named for the stainless steel alloy from which is it made, uses a very simple three-piece design that will eat any kind of presta valve and seal brilliantly in an easy push-on, push-off motion.
But for certain applications, the 17-4 head is no good. Specifically when we're talking about disc wheels. For that, you're either stuck with a tiny disc adapters (of which, Silca already makes a best-in-class example), or you're looking at one of the higher-end locking chucks. Hirame released the original, and until now, perhaps the best example of this kind of pump head. And its time-tested design makes it still a favorite among many a Pro Tour mechanic. But finally, Silca has ironed out all the kinks in its homage product, the Hiro v.2, and the result is stunning.
Every piece of the pump head has been revisited from its original version, and improved in nearly every way. The dimensions of the head have been tightened up, so that it can fit in tighter disc valve hole cutouts. The offset clamp lever (one of my few complaints about the original) has been swapped with an easier-to-use in-line lollipop lever much like the original Hirame. And the rubber O-ring used to eliminate slop in the original has been replaced with a much more functional spring washer, which completely eliminates the slop, while keeping the lever action as light as if it weren't there. This is a very nice improvement over the O-ring, whose presence required greater force to move the lever.
Perhaps the most potent improvement in the Hiro v.2 is its new gasket. Silca originally engineered a two-stage gasket for the Hiro v.1, attempting to port some of the design features from its 17-4 gaskets to the smaller form factor. But in practice, there's so little material in the smaller Hiro gasket that it was more prone to tears (and therefore, leakage). This was my biggest complaint about the original. The new version has moved to a single-stage gasket (sadly, not backwards-compatible with the original Hiro). The single-stage gasket works a treat, sealing on everything I gave it without complaint, without showing the slightest wear. The gasket is basically just a cylinder, molded with a threading detail on the inside (presumably to help grip threaded Presta valves a bit better). I'm not sure whether the threading detail actually improves performance, but it certainly doesn't hurt.
Every last detail has been addressed, right down to a new inverted diamond knurling pattern
Even the tiniest details like knurling patterns have been revised. The original Hiro had positive diamond knurling (the diamonds were raised, the space between them recessed). The new version has inverted knurling (the diamonds are recessed, and the space between them is raised). It's a tiny detail that actually makes a difference in use - the inverted knurling is a bit easier on the hands while still providing enough grip to be useful. And as a final touch, the bolt on top of the pump head has been swapped out for a custom one machined out of the same 17-4 Stainless as the Presta Head, meaning the Hiro can now magnetically snap on to the base of the SuperPista Ultimate pump. It's a slightly less powerful magnetic connection, since there's less surface area on the Hiro. But it's useful nonetheless, and you can still pick up the pump by its handle without unseating the magnet.
I can safely say that this new head very cleanly unseats all others as the top-performing head on the market. It's a beautiful piece of engineering, and will last its owner more than a lifetime of use. Last time around, I had some small critiques about the Hiro. This time, I have none.