I'm building my first road bike, which means I'll have to find appropriate bar height through personal experience and cut the fork steerer in process at least once. I plan to start with the following combination, from down to top:
- 8mm conical spacer that came with headset.
- 20mm and 10mm spacers.
- 40mm high stem.
- 5mm spacer.
In summary, 38mm before stem, 5 after, resulting in total of 83mm of exposed steerer after cut. The fork has 1 1/8 inch (~28mm) tapered carbon fibre steerer, without metal liner inside. Headset is integrated, upper bearing is almost flush with head tube.
Will it be safe or I'll have to cut shorter? Fork manufacturer did not answer the question. I do not plan to ride out of saddle too much, at least during initial fitting, so bars won't experience significant load, and I'm pretty lightweight.