Shortening an Alpha-Q fork steerer tube

[Louis]

I have a new Alpha-Q fork I'd like to use on a frame I'm building up. My problem is that I'm not 100% sure how much steerer tube to have protruding above the top of the head tube because I'm not yet sure a) where I want the bars on this bike, and b) what angle stem I will finally end up using.

The issue with the Alpha-Q steerer tube (in case you are not familiar with them) is that it comes with a short aluminum insert which you glue into place at the top, after the tube is cut to length. Presumably this is to the strengthen the steerer at the stem clamp area.

Say I remove 1 cm from the steerer tube now, then glue the insert, and at some point in the future decide that I want to lower the stem 1.5 cm I'm stuck with a not so good looking 15mm spacer on top of my stem and another bad thing - the bottom of the stem clamp might well end up below the insert, in an area that is not strengthened by the insert. I can avoid having the spacer above the stem by cutting the steerer, but still have the problem of now having the stem partially clamping the tube below the insert.

Bottom line: Any potential solutions to my dilemma? Has anybody else faced this problem before? (I can't be the first one.) What did you do?

Thanks
Louis

[NateM]

Louis,
you can remove 2cm of steerer tube after glueing the plug. From True Temper,
"Q: Can I resize my carbon steerer fork after the insert has been installed?
A: Yes, you can remove up to 2 cm of steerer after the installation of the insert."
or you can use a expanding plug until you decide to glue the insert.I believe problem solvers makes one that will fit,Excel sports has them.I wouldnt worry about the stem clamping force and remember to measure thrice.

[Louis]

Hey Nate,

That's great news. I was not aware of either of those options. I will seriously consider the expanding plug until I can figure things out.

Thanks
Louis

[rmsmith]

I would also buy a stack of different length spacers; when you find your sweet-spot it is nice to use a single spacer rather than a pile of small ones.

[Dave]

Most expanding plugs will not fit an Alpha-Q fork because the wall thickness is thinner, making the ID larger. In addition to that, the aluminum tube does more than just hold the start nut in place. If you read the instructions, the steering tube has a limited length. The aluminum support tube is supposed to extend below the bottom of the lower headset bearing to strengthen this area of the steering tube.

There are also different lengths of support tubes. Some are only 100mm long and others may be 125mm, permitting a longer steering tube.

How much you can cut off depends on how much support tube remains below the bottom of the star nut. Some tubes have a larger ID just below the star nut that limits the amount that the nut can be driven down to only 15mm. Others may be the same diameter all the way to the lower end.

All that said, it should be possible to drive the nut down enough that 20mm can be cut off, if necessary. The nut is positioned lower than it has to be to start with. As long as the top cap doesn't hit it, then there's no problem.

[cadence90]

What NateM said, re: the cutting: you really don't need that top overlapping lip. if the insert is glued in well.

What a great fork.