I've now done two 300 km rides, one last September and the other just this past weekend. Both times I finished feeling both mentally and physically beat to crap (though the second wasn't quite as bad as the first). The thought of doing another 100 km seemed completely out of reach in both cases.

How do you make the leap to the next distance? I know there's a large psycological component to these rides...150 km into a 200 km ride (3/4) feels a lot different than 150 km into a 300 km ride (1/2). Does that carry through to longer distances?

Any other tips or tricks?