I have been fueling this debate on other sites, and while I understand lightness is always a top priority when pondered against strength in the MTB industry, I still believe the idea has some merit. The added support for the tire sidewalls when carving turns would just justify the changes, and we would also kiss good bye the snake bites.
Tire beads would certainly need to grow more bubbly in order to be hooked to the interior of the rim, but I don't think extruding the profile in aluminum would be any more difficult than with the existing profiles. We already have multi-chambered aluminum rims, such as Kore's latest creations.
I'm still wondering why the rim makers are using the same design originated in road racing, where the tire profile usually follows up the rim sides. Those things are designed to bring vertical support for a heavily inflated tire, while we on MTB use tires which balloon away from the rim. The proclaimed merit of the hookless sidewalls is another thing leaving me speechless. Why can't we think of a rim profile/bead hook combo that drives the impact forces laterally rather than vertically? Something resembling more of a "D" shape, rather than a "A" one. And make the sidewall end in a rounder shape, just like the dirt/MX bike rims do.
I understood a different way of integration from the PB piece. You could effectively devote one of the right hand shifter buttons to operate the Reverb, but you'll have to map the other shifting function to the left hand pod. Kind of the way those Rohloff thumb shifters work, one on each side of the handlebar. From the looks of the right hand pod, the front paddle is nothing but an extension of the rear set, and works merely by having a different push point, with an effectively bigger leverage than the rear one, since it's farther apart from the rear pad's pivot point.
Yup, I get your point on padding versus cinching, but I was trailing on the "rounder shape" and "slip-plane equipped" characteristics of the Viva. They do also offer superior venting when compared to the Kali.
Not that they are my cup of tea, but several of my friends use them, and have crashed pretty hard on them, with good results.
While on the subject of rounder shells and MTB, Bern makes some interesting stuff, really worth a look. They do integrate MIPS in their more sophisticated options, and at a fraction of other brands' offers. Plus they are way more vented than the classic bucket helmets such as this Kali Viva.
This might sound stupid, but after our last alpine trip, it started to make sense: Carry a few extra M5 and M6 bolts in your stash. A friend lost one of his dropout screws after all the rattling from descending over 2000 vertical meters along 36km, and a spare brake adapter screw saved the day for us. It was either that or a 10km walk to our shuttle back home.
Spare me my Sheldon Cooper moment: IRT and IVA are AIR chamber modifications, not hydraulic ones. The former one consists of a dual positive chamber, while the latter one it's Manitou's way of referring to volume spacers. The bottom out adjustment It's called HBO. They are all present in the actual Mattoc line.