I like the 992 for the Diablo Challenge a lot. I have ridden the south side and as I remember it is climbing from the start. I have raced the north side a couple of times as a 10K ITT and therefore not all the way to the top. The north starts out flat to rolling and then pitches up. A couple of races have used TT bikes with a disc / fast front wheel to do the 10k due to the flatter start. So I would suspect a lower VAM for that climb. I do not recall my VAM from the north side.