Moving brake and gear levers on a new bike with carbon bars, what should I torque them back up to?
And seat post collar also?

I torqued the lock on collars to 6Nm and the brake levers/shifters to 4Nm on the basis that i’d want them to move if when I hit a tree or such.

Torque to the lower of any spec shown in the brake/gear manufacturer manual. Their specs are fine for carbon bars. Usually about 5Nm, maybe a little more. Generally now I just do up by hand. Nothing crazy, just enough so I’m happy they won’t move with a bit of effort.

Seat post collar, just use as you’d normally use. Seat post is inside the seat tube so you’re very unlikely to damage the seat tube if it’s carbon. Carbon seat posts are very tough and will cope with the clamping force of a collar if used normally.

Use carbon assembly paste on contact surfaces.

It’s a carbon frame, so was concerned with how much “squish” the seat tube would take, I’m guessing the same as the bars, 4-5nm

The post inside the frame provides the strength. You won’t crush the seat tube. Don’t tighten without the seat post inserted though. Torque required is enough to prevent the post slipping when sat on it. Depends on your weight. Again, use carbon paste. You’ll need less torque to prevent slipping. Also helps prevent bonding between alloy and carbon if the two are different.

Also don’t run the collar reversed thinking that it will avoid getting mud in the seat tube gap. I did that and my carbon frame started cracking on the opposite side where the collar clamp closes. The whole point of the gap is to flex and should flex together with the same gap on the clamp.

The post inside the frame provides the strength. You won’t crush the seat tube

Sweeping generalisations ahoy! You certainly can damage a frame by over tightening a seatclamp. 5nm is the limit on some clamps and posts as well.

I speak from experience. Or maybe just On One make their c456 very tough 😉 Gone way beyond 5Nm, and have to else the post slips in my frame even with carbon paste.

Had the same advice from others though. The post inside will generally prevent the seat tube from flexing far enough to break it if you clamp it normally. More so if the post is alloy. Yes you can ultimately break it, but you’ll need to use enough strength that you’d likely be breaking the post as well.

Don’t fear breaking carbon basically. It’s tougher than you think.

I speak from experience. Or maybe just On One make their c456 very tough Gone way beyond 5Nm, and have to else the post slips in my frame even with carbon paste.

You speak from experience of one frame, and apply that to every frame made of the same material. That’s a sweeping generalisation. I didn’t say you hadn’t ever had a carbon frame.

Most bike parts are over engineered to account for a bit of “gorilla factor” in tightening. Not all are. I’d say the C456 definitely is, not sure if your smiley was ironic. It’s a heavy hardtail frame. The same likely doesn’t hold for a 700g road frame with an 80g seatpost.

This:

Don’t fear breaking carbon basically. It’s tougher than you think.

is another sweeping generalisation, and a really shit motto to live by.

I stand by what I say. Carbon is far tougher than people think. There’s way too much fear that carbon is plastic (it isn’t) and will melt just by looking at it.

It’s like carbon bars, sure plenty of pictures where they’ve snapped but usually no evidence that they snapped in any way different to an alloy bar snapping or that carbon was the primary cause.

The same likely doesn’t hold for a 700g road frame with an 80g seatpost.

Fair enough. I keep forgetting I have to consider road bikes on here 😉

Fair enough. I keep forgetting I have to consider road bikes on here

Replace with 900g hardtail frame if that makes you feel better about your inferiority complex?

I stand by what I say. Carbon is far tougher than people think.

How tough do “people” think it is? 8? 14.6? 192?

“I speak from experience. Or maybe just On One make their c456 very tough Gone way beyond 5Nm, and have to else the post slips in my frame even with carbon paste.”

remember anecdotes are not facts .

sounds like your seat post and or frame are out of tollerance- knowing on one , thatll be the frame then 😉