Bicycle Mechanics - grease or no grease?

My local mechanic told me to never to use any thing in the seat tube or the steer tube where the stem clamps onto. No grease or anti seize compound. Is that true? I have always use a little grease on all my carbon bikes without any issues. What do you guys think?

Maybe not grease for carbon components, but this is more suitable:

http://www.competitivecyclist.com/product-accessories/2011-Tacx-Dynamic-Carbon-Assembly-Paste-3321.52.1.html?utm_source=Google&utm_medium=Google%2BBase&utm_campaign=Datafeed

If you are clamping a carbon part like a seat post or steer tube you are not suppose to use regular grease. The reasoning behind this is that it will cause you to apply too much clamping pressure (in an attempt to prevent slippage), which can damage the carbon and lead to failure. They do make special carbon assembly compounds which are designed to increase friction between carbon parts so you wont need to over tighten them.

I used carbon assembly paste back when I had a carbon seatpost. My fork has an aluminum steerer. I do not grease the steerer/stem interface. I want that stem to stay put.

I thought only the moving parts needs lube?

I thought only the moving parts needs lube?

When you take the stem and seatpost out, they move. ;)

When you take the stem and seatpost out, they move. ;)

+1.

I thought only the moving parts needs lube?

I also use grease on all threaded fasteners. Grease is a cheap "anti-seize" compound that makes disassembly easier in the future. You can buy real "anti-seize", but for the type of exposure that bicycles get, grease works fine. (I work with the offshore equipment and anti-seize is mandatory in a salt water environment.)

I thought only the moving parts needs lube?

Using grease, assembly paste for carbon or anti-seize for Ti prevents creaks. Grease and anti-seize are to ensure disassembly is possible.

My Trek owner's manual says to never use grease on a seat post in their carbon fiber frames.

My Trek owner's manual says to never use grease on a seat post in their carbon fiber frames.

What do they suggest you use? Nothing?

Assembly paste, is that what I need?

But wouldn't greasing the seat post make the seat easy to drop down, which is unwanted (the other day my QR seat suddenly dropped to the lowest during a ride).

But wouldn't greasing the seat post make the seat easy to drop down, which is unwanted (the other day my QR seat suddenly dropped to the lowest during a ride).

I use grease on my seatpost and never had it drop down. And for carbon seatposts, we've used a light amount of grease. You should be torqueing carbon anyway. Torque it to the max setting and it shouldn't have problems with slipping.

Assembly paste, is that what I need?

For anything carbon, I would use assembly paste. For example:

http://www.finishlineusa.com/products/fiber_grip.htm

Carbon assembly paste is designed to increase friction. That often means that you won't need to torque to the maximum.

I've use just a thin layer of grease on all my metal to metal interfaces on my bike including Steerer to stem and seat posts and handlebars. I've also used grease on my carbon parts but not as much as usual.

To sum it up:

metal to metal: use grease (keeps parts from seizing).

Carbon to anything,: use carbon assembly compound/paste (helps increase friction so you don't risk crushing carbon with more installation torque).

For "anti-seize" and disassembly ease, isn't WD 40 good enough?

For "anti-seize" and disassembly ease, isn't WD 40 good enough?

You've obviously never worked on an old rusty bike. Grease is a lifesaver for metal-to-metal contact. Look up "stuck seatpost" if you don't believe me. There are plenty of threads where people have had to cut or ream out seatposts because they're so stuck. I've never had to go this far, but did stick a post in a bench vice and use the whole bike frame for leverage to work it off.

For "anti-seize" and disassembly ease, isn't WD 40 good enough?

No.