Headset adjustment - Bearing preload

[SuddenImpact]

Gents, Ladies.
 Ive just dropped the stem on my Defy advanced. 

Hoping someone can advise me on tightening the top cap enough but not too much.

 As per park tool website instruction, ive tightened it just enough to remove any play in the fork. No play, steering feels smooth BUT once its all done I can spin the spacers under the stem by hand. Not easily, there is resistance, but it is possible to spin them.

Is this normal? Or would this suggest there is not enough bearing preload. 

Thanks in advance
Tim
 

[Mulger bill]

If you feel no fore and aft movement when you clamp the front brake on and feel the headtube/fork junction while rocking the bike then it's right. Retest after your next few rides just to be on the safe side.

[greyhoundtom]

Gents, Ladies.
 Ive just dropped the stem on my Defy advanced. 

Hoping someone can advise me on tightening the top cap enough but not too much.

 As per park tool website instruction, ive tightened it just enough to remove any play in the fork. No play, steering feels smooth BUT once its all done I can spin the spacers under the stem by hand. Not easily, there is resistance, but it is possible to spin them.

Is this normal? Or would this suggest there is not enough bearing preload. 

Thanks in advance
Tim
 

Mmmm that is exactly the method I use to ensure its tight enough.

I tighten the top cap until I can't spin the spacers anymore.

[Uncle Just]

IME some spacers are just a tad bigger in their internal diameter and therefore can be rotated or moved slightly even after setting the correct preload with the top cap bolt. Also make sure the stem is sitting right down on the spacers before tightening.