Originally Posted by
kevinf1990
This is the frame that I got (
https://www.giant-bicycles.com/us/tc...-frameset-2020). I do have a torque wrench for when I worked on cars, it is also able to go to lower torques such as 5nm. I think I would use this bottom bracket (
this)? It came with a compression plug
This is the first time I've seen this. I guess the videos that I see on youtube were mostly aluminum steerers which uses a star nut. I think I just drop this into the steerer and tighten the bolt on the top? The outside is a "sandy" texture, would I still need to put any friction type paste on it?
First-off - good for you for taking this on - if you're any way mechanically inclined, it's pretty straightforward and very satisfying.
A couple of things - a torque wrench for most automotive applications will have quite a high range (mine are, for example, 20-100 ftlb and 50-250 ftlb, or something like that). 5Nm is likely at the very bottom of the range, and torque wrenches and to be inaccurate at range extremes. I personally wouldn't use an automotive wrench for a 5 Nm application, like installing stems or bars - get yourself an inexpensive beam wrench in a range more appropriate for the purpose - something like, maybe 2-10 Nm.
You're not going to be able to gauge how much to cut the steerer until the bike is near-complete - at least until you can sit on it. Once you're at that stage, position the stem with as many spacers underneath as necessary to achieve the required height. Then mark the steerer maybe 1" higher than the stem and cut. I use a cheap threadless stem as a guide for a nice perpendicular cut. If cutting a carbon steerer, many recommend a specialized hacksaw blade - I have always used a new standard blade, putting relatively little pressure on it, so the blade does the cutting - you want to cut through the CF fibers, not rip them apart. I keep everything wetted down with a hose to keep CF dust down. I also cut outside. I finish off the cut edge with some wet sandpaper. This approach has always worked for me. Once the stem is cut, you'll need to add further spacers that extend ~3 mm higher than the cut steerer. If a CF steerer, you'll need to position the expander plug so that it is located inside the steerer level with the stem on the outside, to support the steerer against the stem clamp pressure on the outside. Depending on how much steerer you left above the stem, this might necessitate a longer stem cap screw. Your LBS should have a bunch of these in their spares boxes. Once the stem is installed and you start riding, you can fine-tune the stem height, shifting spacers from below to on top and vice-versa, as necessary. Take you time to get it right. The last time I installed a fork, I rode the bike for a year before I finally committed to a "perfect" stem height, finally trimmed the steerer and did away with the upper spacers (I don't like the look of the steerer sticking up above the stem)