Quill stem (with a cone)

[fossyant]

Rulz are 'slam the stem'.

Just get a new stem, not worth the risk.

 

[Ajax Bay]

Rulz are 'slam the stem'.
Just get a new stem, not worth the risk.

I think the rulz fail to take into account quill stems.
Don't you think that satisfying Rule #44 with a quill stem is sufficient and allows Rule #45 to be left to the A-head crowd.
https://www.velominati.com/ for those without a well-thumbed copy.

 

[presta]

Thanks - but if I measure from the bottom of the stem then my current one is long enough.

Then you need a longer stem. Halving the amount of stem inserted doubles the load on it.

 

[Ajax Bay]

Then you need a longer stem. Halving the amount of stem inserted doubles the load on it.

Would you care to explain why you think that is? And if it is, does it matter?
Surely the requirement is that a sufficient length of stem is inside the (threaded) steerer tube with friction generated at the cone end (by applying tension to the stem bolt) to ensure neither up/down nor rotational movement. The bending moments generated (fore/aft and side-to-side, not rotational) will be dependent on the max force (hands on handlebars) x the length of stem NOT inserted (strictly the radius from top of steerer tube to handlebar (c-c)).
Provided those moments are below the design strength of the cylindrical 22mm OD stem (by a safety factor, by design), the anchoring mechanism (50mm inserted) is entirely adequate.
The cone and wedge mechanisms do not differ significantly in fastening effect. The OP has been advised (see the Sheldon 'authority' shared above by @ColinJ ) to insert the stem at least 2". The split is normally about 12mm so it will be well inside, and thus not an issue. They have said:

if I measure from the bottom of the stem then my current one is long enough.

On your quill stems @presta , what is the minimum distance between the bottom of the stem and the ||||| minimum insertion band?

 

[rogerzilla]

The rule of thumb is that the expander (wedge or cone) needs to be below the threaded part of the fork. Some forks have very long threads, in which case this may not be possible, but then you want to have even more quill in the (weakened) steerer.

Stems with very long quills are made by Nitto and Zenith (try VeloSolo).