Jim’s Tech Talk
By Jim Langley
Back in June we reviewed Silca’s top-end pump chuck, the Hiro. Pump “chucks” are also called “heads.” They are the mechanism found on the end of pump hoses that attach the pump to the tire valve for an airtight connection.
The Hiro is a versatile chuck. It can be used as an adapter that fits into the built-in pump chucks on most pumps. This comes in handy when the pump’s own chuck doesn’t fit or refuses to provide an airtight connection on the tire valve.
The Hiro chuck is also made to thread onto the threaded end found on the hoses on Silca’s full-size pumps. Plus, if the head on another brand of pump were to fail, you could cut the stock head off and use the nozzle end that’s included with the Hiro to attach it to your pump as a new chuck to fix the pump.
The Other Super Chuck
The reason I’m doing this follow-up on chucks is because at the time of the review, reader Tim Evans commented,
“Basically, the Silca Hiro (most recent version) is a copy of the Japanese Hirame HP-20 pump head, available from Jitensha Studio in Berkeley, California. I have both, and the original Hirame is easily the better of the two. Both are a pleasure to use.”
That was great to hear because I had been looking at the Hirame head before purchasing the Hiro. So, wanting to see for myself how the Hirame was “better,” I decided to order one and called Jitensha. When it arrived, I was surprised to discover an important difference between the two chucks.
And the difference made me want to write more about these chucks in case you read or were to read Tim’s tip and decide to try one. Since I bought my Hirame ($65) I discovered that it’s also available on Amazon. This gave me a chance to read the questions and reviews and made me realize that there’s confusion about it.
Please note that we’re talking about using these chucks for inflating tires/tubes equipped with Presta not Schrader valves. Presta valves are found on most road bikes these days but Schrader valves are still out there on older 10-speeds, so I want to make that clear.
Why A Good Chuck Is Important
I think you can make the case that the home pump (sometimes referred to as the “floor pump”), is among the roadie’s most important tools. Because road tires lose air quickly and must be inflated frequently. With some tires you might need to do it before every ride. Which means that owning a nice pump can make the difference between quickly and easily topping off your tires versus frustration and delays before every ride.
Limitations With Most “Standard” Pump Chucks
Most production pumps come with proprietary chucks and while there are almost endless designs, the majority work similarly. You press them onto valves before locking them in place with the built-in lever.
Because the Presta valve is open when you do this, pressing the pump head on usually pushes the valve tip down opening the valve and releasing some air. If a person is fumble fingered when putting on this type of chuck, they can lose a lot or almost all the air in the tire meaning more pumping is required. If you were trying to only top of the tire before a ride this can be annoying.
Even more maddening is if you end up bending the valve tip when trying to get the pump head to stay put, which is actually a pretty easy mistake to make. You can bend it back gently with pliers, but if you’re not careful you can break it. On some tubes Presta valve cores are replaceable and if you have a spare you can fix the valve and save the valve. But on non-replaceable-valve cores, you’re out of luck and will need to replace the tube.
If you have a pump with a chuck that screws onto Presta valves, it may work perfectly fine and if so you can stop reading. If it’s not airtight, though, you might want to consider switching to one of the super chucks.
Benefits Of The Hiro And Hirame
There are two advantages to the Hiro and Hirame chucks. First, their opening is large enough that when placing them onto the valve, you won’t lose air unless you bump into and depress the valve tip. And second, they feature a side lever that locks the chuck on the valve. Closing it operates a cam that compresses the rubber grommet inside the chuck, that seals and locks the chuck on the valve.
In comparison, when you use the press-on chucks found on most pumps, you press down or pull up to lock the lever risking damaging valves from the amount of force required with some of these designs. With the Hiro and Hirame’s side levers, there’s hardly any pressure on the valve when locking or opening the chuck.
But, the biggest advantage is an airtight connection first time, every time. With standard chucks, it’s common to put them on and then have them leak at a certain pressure. Then you have to remove and reposition them and start pumping again. Sometimes it takes several attempts before you get enough air in the tire.
How The Super Chucks Differ
The big difference between the two super chucks is that the Hiro has a 6mm diameter nozzle and the Hirame’s is 7.2mm (photo). This allows the Hiro to fit into regular chucks and work as an adapter to get an airtight connection. Another great use is for short or hard to access valves, such as those on the one-piece aero disc wheels for time trials or triathlons. And, it will even work with mini pumps for on the road saves.
The Hirame’s nozzle is too large to fit into standard chucks, so it won’t work as an adapter. Instead it’s designed as a replacement for a bad, inferior or worn-out pump head. To use it, you remove or cut the bad chuck off the end of the pump hose. Then you insert the Hirame’s nozzle into the hose and fix it with a hose clamp. In other words, it’s a dedicated upgrade chuck you add to your pump to replace what came on it.
The cost of my Silca Pista pump is $99 and adding the Hiro is another $65, for a total of $165. If you upgraded to a Hirame chuck, it would add the same to the cost of your pump. Talk about inflation – those prices are a lot for a bike pump! (Sorry, couldn’t resist.)
But, if you’re fed up with lousy performance from your otherwise nice pump. Or, if like me, you rely on your pump, I believe it’s worth the bucks to have a pump that just works and on anything you throw at it. I can’t tell you how many times at races and rides I’ve pumped up tires for people who couldn’t get the job done with their pump.
Also, unlike the plastic thumb lock heads built into most pumps, both these super chucks are built out of steel, for a lifetime of dependable use. I think you can see the quality in the photo.
Ride total: 9,052
Jim Langley is RBR’s Technical Editor. He has been a pro mechanic and cycling writer for more than 40 years. He’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Check out his “cycling aficionado” website at http://www.jimlangley.net, his Q&A blog and updates at Twitter. Jim’s streak of consecutive cycling days has reached more than 8,000. Click to read Jim’s full bio.