2 of 2 customers found this review helpful.
Got this to replace the Brass Bell of my ancient Silca pump, and it installed great on the original hose with no leaks. Great, right? I thought so. And then I noticed the bizarre dual schrader-presta arrangement. This head works great on schrader valves, but not presta. To get it to work on a presta valve, you've really got to jam the head on the valve body in order for it to grip, because the narrower part of the rubber seal inside is furthest from the mouth of the head. Also, the brass pin in the middle that's meant to open a schrader valve, floats in the center until you tighten the clamp. The problem with this is, unless you've jammed the head on the valve far enough (if your presta valve doesn't protrude far enough out of the rim, this is impossible to accomplish), you won't get a good seal. In any event, more often than not, because the pin opens up the valve while you're trying to get it on far enough to make a good seal, half or even more of the air in your tire will come out and you'll be pumping a lot more than just two or three strokes like you would otherwise.
Once you've got it properly inflated, when you release the head's clamp, it's a crap shoot as to whether half the air will come out while you struggle to get the head off, because that floating pin gets stuck and all of a sudden you've got a half inflated tire again.
I've used pumps on bike tours that worked much better than this, because they were built for presta valves, not both. If this head used the old system of simply flipping over the rubber seal to accommodate the different valve stem diameter, it would doubtless work much better.
Thank you for your feedback.