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Old 05-21-12, 11:33 AM
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AndreyT
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Presta valve base failure

Yesterday, as I was standing next to my bike at home, I suddenly heard the sound of air escaping the tube. Turns out my rear tube suddenly developed a large leak, right out of the blue on stationary and unloaded bike. I immediately replaced the tube with a spare. Inspection showed that the reason for failure was the rupture at the base of the smooth-stem Presta valve. Obviously, the main reason for this failure was the repetitive stress experienced by the rubber at the base of the valve from the pump head, as it was attached to and detached from the valve. Fortunately, my new tube has a threaded stem with a nut, which will protect the tube from experiencing this sort of wear.

My front tube also has a smooth-stem Presta valve, it was installed at the same time as my rear tube and it was pumped up with the same frequency. Taking this into account, I wonder if I should preventatively replace the front tube as well...

Anyway, a question to people who use smooth-stem Presta valves: what steps you take to prevent or minimize stressing the tube as you attach or detach the pump head? Is there some sort of technique the would allow one to attach the pump without pushing the stem in?

Last edited by AndreyT; 05-21-12 at 11:49 AM.
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