I've got a pretty big saddle to bar drop on my XC bike, so the cross bike didn't have a huge aerodynamic advantage.
Maybe that's it as I have done 'tests' when messing around with bars before and going from risers to drops but with all other factors the same and I was quicker on the same bike with just the bar change.
On less than challenging terrain then I guess it is really down to the fitness assuming wheel/tyre weights are close (for the uphills) as the bike is not being asked to do much more than it would be on the road.
Maybe that's it as I have done 'tests' when messing around with bars before and going from risers to drops but with all other factors the same and I was quicker on the same bike with just the bar change.
On less than challenging terrain then I guess it is really down to the fitness assuming wheel/tyre weights are close (for the uphills) as the bike is not being asked to do much more than it would be on the road.