What gear ratio are you running?
On this ride I was running 49x13. I've recently swapped the cog for a 15T to level things out a bit.
Damn, even with 49/15, with an average speed of 27km/hr that's an average cadence of like 65. I used to push 53/16, now I run 53/20 which I can comfortably run 32-33km/hr average.
Yeah, the issue with this ride is that I was riding with several other people and maintaining their pace (which is slower than when I ride alone.) But you're right, far too high a gear.