I have also noticed the rear feels less stable while running the Fatty as well. Seems to be a theme here with several riders feeling it too. I'm running a 130 Michelin S12 Mid soft with a heavy tube and 13psi. I plan to run the new Kenda K787 tubeless so I can run 4 psi. I called Kenda and Dennis Kirk last night to find out why the 787 still hasn't showed up(Early March was claimed arrival). Kenda says they started getting containers however the tires received were for the race sponsored teams and the distributors shipments are due any day now. I have 2 on order and plan to run one in West Arkansas single track next month if get it in time.
Just tried out the fatty this weekend in mostly slick mud and hilly terrain best front Ive ever had. Ran it 13psi and I also tried the Sedona mx907hp found it worked best at 7psi but going to try down to 5psi. I was running Tubliss.
Thanks DM for the suggestion on the Battlecross. I got to try it yesterday on a very unique day that started out dry and dusty, then turned to light rain, then to snow. It was on par with the GT216AA. In fact braking traction is maybe a little bit better.
I like the Motoz Tracionator ST paired with the fatty , only rear that I have tried that seems to have close to the same grip as the 216
