Originally Posted by
bdcheung
Why do the call them compression plugs when the "plug" actually expands?
I think the reason is because the purpose of the plug, and the cap is to compress the stem down on the steerer tube, to preload the headset bearings.
As for function, all its got to do is 1) not damage the steerer, and 2) hold the stem down on the steerer, until you tighen the stem.
So I'd agree the lightest that works would be preferable.