Low stack height stem

[mcrocker]

Thanks all for the help here.

I have interrogated the top part of the headset (it is a Diatech) and there is 35mm steerer left to play with (it's a 1" with a 1 1/8" shim).

But there is a 5mm thick (vertically) washer with an allen bolt to tighten it onto the steerer below the stem (says Diatech on it) and I can't see the point of that given that the stem has a star nut and a routine aheadset clamping system. This washer has a bevelled lower edge that sits over another washer that then sits on the top headset race and I can't really see what the point of them is: if I could get rid of them I would have another 5mm of steerer height which would take it to 40mm.
I am SURE I am missing the point here but thought I would ask the collected wisdom as I would like to know why I should not be removing this bit: or alternatively if I can(?!)
I have bodged a quick cross-sectional diagram here: the bits I would be interested in knowing the function of or getting rid of are called "Big allen clamp thing (Diatech) and "Bevelled washer thing."

 

[FluffyChicken]

as far as I know (from 30 seconds of a google seach) you throw that allen bit away for aheadset setups. It's there is you fit a threaded fork/steerer.
It can be used for both, so keep it.

EDIT scrap that, that is the top nut you would have if you bought the headset. You need to keep that clamp bit as it's the bit that pushes on the compression bit I assume.

assuming it's this

which actually is this from my guess

pinched from
http://www.ohio.edu/people/urieli/stemc ... clamp.html