Post ride observations.
As I mentioned in an earlier post, I was expecting my Go Lite back back to arrive and it did yesterday. So of course..., I had to test the feel. I ran two test runs in my neighborhood of 5 miles each (limited time). Loaded the pack with my gear minus the water, as I figure water will be mounted in the cages, and the pack came in at 13 lbs, 6 ounces.
First test set was to strap the pack onto my Maya Trailer and ride the loop. Initial thoughts were to get some legs warmed up and see if a light pack traveled well on the trailer. Second test was to dismount the trailer and just wear the backpack. My results were that I came in one minute faster with the backpack on with approximately the same conditions. Much like the above comments, I have to agree that the trailer is for heavier loads...not an option with the pack, but was hoping I could go from riding to walking in short order.
The ride with the pack on was amazingly stable. I had some wind on both rides, but experienced no top heavy issues. Matter of fact, the aerodynamic feel of the pack on was much better than what I have experienced with panniers. Your body does much of the cutting of the wind and the pack does not affect drag like panniers sticking out on the side of the bike. I did ride sitting on the Brooks saddle instead of out of the saddle like Bikenh, so yes. I did feel the difference by the end of the ride more than I would normally. My butt was a little tender, so I think this is something you would have to condition yourself for, but not insurmountable. Granted, both of these were short rides and not completely conclusive..., just wanted to get in a test. Will have to try again on a longer ride to see what the bum feels like, but I think it is doable.
My my back was a non issue. Yes I felt the heat and sweat, but nothing any different than when I am backpacking. No issues with back pain and I was able to still use the mirror on my helmet yo see traffic. All in all a good test.
Initial thoughts are that the real ultra lite set up is to take the load I had in my pack and just use two panniers up front to transfer that weight over the front wheels since most of your body weight is situated over the rear wheels. Leave my trunk bag on the rear rack with bike tools and quick access items. If I still maintain the same ultra lite load, this might be the best option. May have to look for some lighter front panniers.
Hope this his helps someone that is exploring the same questions.