threadless carbon steerers

the top cap is only there for adjustment as far as i am aware. It is actually possible to adjust the headset and then take the top cap off and ride without it. If the "whole system" comes loose it is more likely that the clamp on the stem (connecting it to your steerer) is loose. Not sure what else to say as i have only had experience with carbon steerer threadless systems.

Tighten it as much as you need to get the headset play out and ajust it.

You do not have to pull out a torque wrench to tighten that.

Quoted post said:

Originally posted by dorian
I recently built a bike and have a reynolds ouzo pro threadless fork with a carbon steerer. I am wondering just how tight can one tighten the top cap on said fork?

I actually couldn't get it tight at first and read some posts about roughing up the inside of the tube and steeer plug (?) I did that and was able to tighten the top cap down enough to eliminate headset play and could tighten it a little more if I wanted, but if I really crank I could pull the plug up towards the top cap. As I haven't put any real miles on the bike my concern is whether road vibration can loosen the whole system over time and if there are other measures I should take (different plug or more sandpaper).

I imagine one can get the top cap quite tight with a steel steerer and star fangled nut and am inquiring how it compares to carbon steerer threadless headset adjustment.

Thanks for any input.

Stop everything and take it back to the shop where you bought it!
Carbon fibre is a brittle material which doesn't give like metal and tubes made from it can be crushed or cracked under overtightening. I wouldn't use sandpaper on it either as you are rubbing away the resin which holds the fibres in place!
Don't do any more on it unless you can get info on how tight any bolts should be.