I pulled the carbon steerer tube and fork off of my Canyon Ultimate. Something was loose in the steering column and I just wanted to make sure that there weren't any cracks in the steerer tube. There aren't, but of course, I cleaned off the steerer in order to get a good look at it.

What's the recommended grease for a carbon steerer? I have Parktube polylube (PPL-1), which I think might fit the bill?

Note that I'm talking about lube between the steerer and the hole in the frame. I know not to grease the top of the tube where the stem will get fastened. For that there is carbon paste -the opposite of lube.

Thanks

Hmm, I just read this on the Trek website (though of course, mine isn't a Trek)

​​​​​​​Agree?

That's a new one on me. I've certainly never seen any wear to the carbon under the spacers from a paste full of plastic beads.

Park poly lube is rated for carbon if you look closely on the can or tube. They do not make a carbon specific grease for this reason. So is finish line premium lithium grease if you are looking for another option, as are finish line brand greases.

I would advise that you don't pack a headset full of carbon grip. It's an abrasive. Whether or not it's hard enough to damage steel bearings is one thing, but it certainly can't be good for an application where reducing friction is the goal. Additionally, using carbon grip on stem clamping surfaces (which could happen if you apply to headset bearings and don't wipe down the steerer) has been known to rip carbon steer tubes in a crash because the stem refuses to rotate due to the increased friction.

Good info. Thanks.

Not applicable. The grip would be applied to the outer surfaces of the steerer onto which is clamped the (carbon) stem, which in the case of this Canyon is part of an integrated stem/bar.

Possibly an important consideration.

I figure that CF assembly paste is only needed if one tightens to the specified torque but there is still slippage. Thus, on my bikes, I only need to use a little bit for the internal seat post clamp, but none for the interface between the stem and the steerer tube or for the interface between the stem and the handlebar.

The problem being that grease might guarantee it slips, while dry mounting can cause the parts to lock together after salt or sugar creep in there. Carbon paste prevents the wrong stuff from getting in while maintaining traction.

I would apply the paste to the inside of the stem so a wad of it doesn't end up just above the spacers.

Why are we lubing a steerer tube?...

The "hole in the frame" ? it's the headset bearings that do the rotation. The steerer turns along with the inside race of the bearings.

At the equivalent contact point for the collar and the frame, my Bianchi has some o-rings in the FSA collar, to keep water out, I suppose. I'd use a lightweight grease that's compatible with rubber and plastic.

At the arrow:

Thanks. I more or less figured this out when I went back and looked at the frame. There are two surfaces, the one you indicated and another set of bearing at the bottom, just above the fork, where there's contact, and those are the places I lubed.