mugatu

I'm building a Specialized S-works Langster and up to this point all the bikes I've worked on have utilized quill stems. I'm concerned about stem clamping mechanisms harming the cf steer tube. Are there any known stems to avoid, or are they all pretty safe provided that I continue to pay way too much attention to the torque wrench during this build? Maybe I'm overcompensating, but this bike seems so light and delicate compared to every other bike I've ever owned, which seem like tanks next to it.

Al1943

Don't use the stem torque spec on your CF steer tube. See what the fork manufacturer says or stop at 5nm. I broke mine at 8 nm, the stem spec.

capwater

I always make sure I have a spacer on top so all of the clamping surface of the stem stays in contact with the steerer tube.

RockyMtnMerlin

I have used Reynolds and Look forks (carbon steerers) along with Ritchey and Syntace stems. If you are referring to how much torque to apply to the bolts on the stem that holds it onto the fork steerer, it is my experience that the limiting factor is the torque that the stem bolts can tolerate. Normally they are an alloy and can't take much abuse. Syntace can take up to 50 inch lbs and Ritchey 45. The steerer on a Look HSC 5 SL can take a lot more than that. In fact, Look gives a higher value and says defer to the stem manufacturer. Hope that helps more than confuses. Finally, don't overlook the fact than Tacx makes a compound that helps the stem grasp the carbon steerer without torquing the stem bolts any more than necessary.