General Cycling Discussion - Question about the Blackburn TP-5 pump useage

In that my girlfriend cannot pump up her tires all the way to 125 pounds (she is a hundred pounder, and some might argue that she does not need to run 125 pounds but that is irrelevant), I found the ultimate weak person pump, the Blackburn TP-5 pump which has both high pressure and high volume modes. In the high pressure mode even she can pump up her tires fully now. The Blackburn pump is incredibly expensive - $100 list so one expects the pumping experience to not be a pain in the butt.

Now in that this question can only be answered by someone who has experience with the pump, I will save the rest of the BS and get down to the particulars. I use the pump as per the instructions. The lever on the pump head is placed in the neutral position, and I then place the appropriate side (presta) on to the valve stem. As soon as I do this, air starts leaking out of the opposite valve. Okay, not a problem, because as soon as the lever is turned towards the side in use locking it on the valve stem, we are back to everything being "normal." The pumping goes smoothly, and now we have reached the desired pressure. Of course the pump head cannot be pulled off the stem unless and until the head is unlocked by turning the lever to the neutal position. As soon as I do this, and even though I move quite rapidly, air starts being released through the schrader end, as soon as the pump is unlocked. Yes, it is pressed completely onto the valve. By the time you rapidly take the head off the valve, and put a tire gauge on, one has lost at least 30 pounds of air.

What the hell am I missing here? The instructions are limited, but clear as to how to use the pump. I find it distressing that I have to use my $20 pump to get on the road because my $100 pump will not do the job. Suggestions, comments from actual TP-5 users/owners?

Oh, and yes, I did call Blackburn (Bell Sports), and they could not answer my question, but simply offerred to send me a new head. The above is assuming the new head will not change anything on a brand new pump. BTW, I also asked them what the device on top of the pump is (a screw cap), and they did not know. They simply advised me not to take it off, because "If you lose it, we don't have replacement parts."

Oh, and yes, I have thoroughly tightened down the fittings on both sides of the head.

When you stop pumping and go to flip the lever, there is still pressurized air in the hose between the pump and the tube. This air will be released through the pump head. Normally, when the outside air pressure drops, a presta valve seals up and prevent all but a very small amount of air from escaping the tube.

In your case, perhaps the pumphead is so far on the valve stem that it is pressing on the stem and holding the valve open. Have you tried not fully seating the pump head to prevent this?

When you stop pumping and go to flip the lever, there is still pressurized air in the hose between the pump and the tube. This air will be released through the pump head. Normally, when the outside air pressure drops, a presta valve seals up and prevent all but a very small amount of air from escaping the tube.

In your case, perhaps the pumphead is so far on the valve stem that it is pressing on the stem and holding the valve open. Have you tried not fully seating the pump head to prevent this?

Interesting try, I will try it tomorrow - thanks.

When you stop pumping and go to flip the lever, there is still pressurized air in the hose between the pump and the tube. This air will be released through the pump head. Normally, when the outside air pressure drops, a presta valve seals up and prevent all but a very small amount of air from escaping the tube.

In your case, perhaps the pumphead is so far on the valve stem that it is pressing on the stem and holding the valve open. Have you tried not fully seating the pump head to prevent this?

Just to clarify your suggestion: I am in a bit of a hurry this morning - need to make the club ride, but I quickly tried just partially putting the head on and then locking it. If that is done, then the plunger is not depressed. I thought perhaps that the pump would generate enough air pressure to depress the plunger, but that is not the case. With the plunger not depressed, no air goes into the tube. It is difficult to believe that a 100 buck pump is so difficult to use. I just grabbed my good old cheap pump, and with seconds I was set, and now its off to hammer with the group.

You can save yourself a LOT of hassle by getting some presta/schrader adapters to make your presta valves functionally into schraders. This MUCH MUCH MUCH easier than trying to pump directly through presta valves, IMO. Many pumps do not attach well to presta valves, and many presta valves are fragile or poorly designed.

You can save yourself a LOT of hassle by getting some presta/schrader adapters to make your presta valves functionally into schraders. This MUCH MUCH MUCH easier than trying to pump directly through presta valves, IMO. Many pumps do not attach well to presta valves, and many presta valves are fragile or poorly designed.

Excellent suggestion. I tried it, and unlike when putting the chuck on a Presta valve, no air escapes when you put it on the presta valve with schrader adapter. Also, it is easier to get off without suffering lots of air loss.