Head Tube Length
What is Head Tube Length?
The length of the head tube, not counting headset cups, steerer tube, or spacers.
Why is it important?
Head tube length can give a general idea of how upright a bike is designed to be, but it is not the most important factor of fit since additional stack can be achieved with more steerer tube spacers or a taller stem. Head tube length is shorter on bikes designed to use with a suspension or suspension-corrected fork.
Some companies design bikes with shorter head tube length to allow for more aggressive fits and to lower Standover Height for riders with shorter inseams. While it is possible to raise the height of handlebars through spacers or a taller stem, this will also have the (intended or unintended) side effect of shortening the horizontal reach to the handlebars. For this reason, comparing bikes with disparate head tube lengths can be problematic.