Review: Silca Pump Heads
Jul 12, 2014
article & images by Nick Salazar
I used to be of the opinion that pumps were universally lousy. They were always a bit cumbersome to use, generally unreliable, and difficult to use in a consistent way. Silca is a brand devoted to eradicating that notion, creating the highest-end pump hardware they know how to manufacture. The brand has been around for nearly a century, founded in 1917 with the concept of making heirloom-quality pieces that could be used for several lifetimes, if given the proper maintenance. Of equal interest is the fact that former Zipp chief engineer Josh Poertner left his post at Zipp, and purchased the legacy company, to manage it himself and lend his considerable talents to developing future product.
TriRig asked for several Silca products to review, and Poertner answered with gusto. We received Silca's flagship product, the bell-shaped 17-4 Stainless Presta Head, as well as their Disc Wheel Adapter, EOLO III mobile-use CO2 regulator, and Locking Schrader Chuck. To a large extent, receiving products to review for TriRig always feels like Christmas, and when the brand is as devoted to quality as Silca, that feeling is even more intense. To that end, Silca and Poertner have one important thing in common: they really, REALLY care about quality. That was an obvious part of Poertner's legacy at Zipp during his tenure there, and is easily the hallmark of Silca's brand reputation. I'm going to review these pieces individually, starting with the pump heads, and then move on to the other parts.
Before we get there, however, I want to talk a little more about pumps and inflation in general. Let's start with the basics.
Good Pump Protocol
In order to talk about the merits of any given pump, pump head, or tire valve, I want to cover a bit of basics. These are the "ground rules" so to speak. The first and most important of these is that when using ANY pump, it must be properly seated before it can be expected to work. In the case of Presta heads, our focus here, that means a certain minimum valve length needs to be inserted into the pump head, so it can achieve a proper grip on the valve and fill the tire. In my experience, that's about 15mm. Less than that, and you'll encounter two problems. First, the pump head might just blow off the valve, ending your pumping journey prematurely. Second, the pump's pressure gauge will swing wildly about, unable to get a proper reading. This is obviously annoying, and not conducive to proper inflation. So, how do you achieve proper seating?
To get a good seal on the valve, you need a balance of two things to occur. First, the head's aperture needs to provide a low-enough resistance to mount in the first place. Second, the head must be able to achieve a good seal pressure. In other words, you have to be able to properly push the valve into position, and also lock it into place. Some pump heads achieve this balance by using a locking mechanism: achieve step 1, and THEN step 2 via locking. In the case of the Silca Presta Head, there is no locking mechanism. You CAN achieve additional pressure by screwing the cap further into the dome while the head is mounted on a valve, but that's not exactly the equivalent of an ordinary locking mechanism (the flip-up lever you're probably accustomed to seeing on common floor pumps). Instead, Silca's Presta Head relies on a balance of mounting pressure and seal pressure so that you can simply push the head onto the valve, inflate, and push it off.
One linchpin for this mechanism to work is making sure that your tire valve doesn't move. That is, when you're pushing the pump head onto the valve, your efforts can be worthless if the valve simply pushes away from the rim. This is often the case with threadless valve extenders, which don't have a nut to lock it against the rim. For optimum performance, you want to be sure that your valve extenders DO have a nut, to keep the valve in place while you mount the pump head. Alternatively, if you're using a valve or valve extender without external threading, you want to ensure you have some extra length beyond your rim's inner diameter (I'd suggest a minimum of 40mm). I know this is very technical stuff, but it's worth weeding through the minutia in order to understand WHY pumps do or don't work. In the case of Silca's stuff, it works really well when used properly. And I'm about to show you why. But before that, there's yet one more thing I want to talk about first, and that's valve types.
The enemy of good pump function is often a mismatch between the valve type you use and the type your pump head was designed for. The most common valve type you're likely to encounter is simply a straight valve with an outer threaded body for valve nuts. Most pump heads are designed, at least, to seal around these. And they do so with varying degrees of success. Regardless of whether the head is a push-on type (like the Silca heads shown in this review) or a locking-type (something with a lever that flips to further close the O-ring's inner diameter), they need to have enough flexibility to accept the valve's outer diameter, while tight enough to hold on during the pumping operation.
But then there's the wrinkle of barbed valve extenders, like the ones made by Zipp/SRAM. Instead of using a straight, cylindrical extension, they terminate in a cone-shaped barb, whose outer diameter flares out, then back in, and eventually returns to cylindrical. These can help ensure a better seal, or they can wreak havoc on your gasket and make things even worse, depending on the design. Some pump heads won't even accept barbed extensions, as I'll illustrate in an upcoming shootout article. In short, getting a good, reliable pumping is a delicate balance of your pump, pump head + gasket, and valve (or valve extender). If one of those links in the chain is weak, the whole process can break down, to the chagrin of many a cyclist.
With that out of the way, let's begin with the pump heads. Hit the jump and we'll get started.