This is good feedback. I like the idea of a frame bag on the full-suspension bike with a hydration pack. I also like the idea of a 20lb carbon hardtail. Right now I bike around with 47mm Terrene Elwood tough tires, which are not the fastest tires, on my 26lb steel-frame bike. I rode 113 miles at 12,470 ft elevation this weekend with this setup (pavement was bad, so I was happy to have this configuration). Since mountain-bike tires consume more watts, and I'm already spending lots of watts on my bike, maybe it will cancel out by getting a 20lb carbon hardtail.