Originally Posted by
10 Wheels
What keeps the rack from rotating around the seat post? Just a good hard clamp?
Also, 6kg is very close to the limit for a typical seat-post rack. With 1kg for a bag, basically you're looking at basic repair kit plus change of a clothes. Any more than that and you'll need a real touring rack solution.
The Felt Z95 is a less than ideal choice. Its an aluminum frame but lacks braze-ons, which many Al frames have. In your situation, I would look at an alternative bike, unless you're getting a killer deal. The Trek 1 series is very similar but has integrated rack mounts.