Originally Posted by
JohnDThompson
They also serve to keep the stem in a radial orientation, reducing the risk of tear flats at the stem base.
John,
I respectfully disagree. (partly). While they stabilize the valve when pumping which is in their favor, they can also mask tire/rybe creep by keeping the valve from moving with the tube, increasing shear stress at the base, and eventually leading to base separation.
I vave mixed feelings on these nuts. I NEVER use them on tubulars, but do leave them on loosely on the fat tired commuter so pushing the head on produces less stress on the tube/valve connection.
These days, with the newer crappier design, valve separation is my No.1 cause of flats. I've found it happens most often because of corrosion causeing a bond failure, especially after rain. These days, I'm using an O-ring sandwich on the valve stem, with the nut closing it tight against the rim, and it seems to be helping, but the jury's still on on this,