Alex Mack,
The 899xt is the full upright, correct? If so you have clearance because the bike gets positioned in front of the front roof bar. Make sense?
Banned bandit,
You have clearance because you do not have the factory rack and therefore are using the traditional "fit kit" clamps. The setup you have is good in the sense that you can purchase any Thule component and it will work fine. However, for those that want to utilize the factory roof rack and do not want the full upright (i.e. take off the front wheel and put it in your trunk or buy the wheel carrier) the tray impedes the tailgate from opening all the way.
Matt