Originally Posted by
Jeff Neese
Update. I bought two packs of these from Amazon. The two that I needed replacements for (with the Continental tubes) worked fine. I also examined them under a high-power loupe and they seem much better quality. The washers are thicker and more uniform, the valve seats are straight, the materials are better, and they just look like they are manufactured to higher tolerances. Even the knurling on the knobs are finer and more uniform.
It's very reasonable to assume that even though high-end tube makers like Conti or Schwalbe do produce good tubes and perform a thorough QA on them, they then go ahead and install valves purchased from the lowest bidder.
Presta Valve Core - 10 Pack
Thanks for the update. I just ordered that same 10 pack yesterday. Couple valves on my tubeless valve stem were not functioning well so I had to grab some new ones from my stash that worked better and replenish my stock.