My new Cannondale Gemini 1000 is having some teething problems. One in particular has been fixed but I'm not sure if what I've done is the correct thing to do.

The right side of the handlebar has the gear change for the rear derailleur. The cable runs down the down tube, around the bb and along the upper swing arm and there to the rear mech. On the swing arm and elsewhere on the frame, there are some cable retainers (if that's the right expression) that have been welded onto the frame and swingarm. The cables are routed through these and the cable is then fitted into a small plastic cylinder (split down its length) and that presses into the retainers.

The cable tension is very tight, and it will not fit into one of the retainers loose enough. End result, is that the cable detached itself from the retainer and rubs on the rear wheel. I 'fixed' this by routing the cable back into its retainer, and then securing it either side with two cable (zip) ties. This is not ideal, and I should take it back to the lbs for a warranty repair, but I'm wondering if what I've done is a viable solution and maybe more mechanically secure than the original?

Are cables that run along the swingarm meant to have more slack than normal?