Originally Posted by
Kopsis
Most manufacturers spec a maximum of 40mm (1.6") of spacers below the stem. More than that and you potentially stress the steer tube and the top headset bearing beyond design limits. Depending on the HT length of the frame you're considering, that may be enough to get the bars where you want them.
??? I have trouble accepting that steer tubes and headset bearings can't deal with 2" of extension. I run a stem extender and it is adding over 3" to the original steer tube. An acquaintance with a bad back got an uncut steer tube for his Rodriguez tandem with way more extension than that. Must be legal or liability issues that make manufacturers conservative. The aftermarket doesn't seem to share their concerns.
H