Gear Combo Guru
Join Date: May 2007
Bikes: Spec' Tarmac (road), Ridley Fenix (commuter & fast tourer), Salsa Mamasita (MTB), CoMo Speedster (tandem), Surly Big Dummy (cargo), Airnimal (folder)
If you want to use a standard stem, for a 1 1/8" steerer, then get a 27.2mm seatpost plus two shims - one for the seatpost-to-frame (27.2 to 31.8mm) and one for the seatpost-to-stem (27.2 to 28.6mm). The stem can then weigh in the region of 150 grams, maybe less, but you are limited to the 140mm maximum length of stock stems.