Another happy Gar-aero owner...who doesn't own Airstreaks.
The "real" TUNDRA tire guys will probably give you a bit more feedback regarding the Airstreaks and Bushwheels, but...The Gar-aero's are pretty good in soft stuff like sand or peagravel.
I limit the big cobbley rock to large grapefruit-size. The distance from the ground to the rim adapter can be squashed-out pretty easily when running low pressures (less than 8 PSI)
They're great for off-camber beaches, because I don't have to worry about rolling them off the rim-adapter when running at 8 PSI. As far as foot-print, I think the Gar-aero's may have as much contact patch as either of the "real" tundra tires. Those adapters are wide, and really spread the tire out, changing the profile and adding width to the contact patch.
If you're going into super-cobbley rock or hummocky tundra, you will want the biggest and softest tires you can get, and Gar-aero's aren't it.
As far as impact absorption, (rolling over, and soaking up, large stones) the high and soft sidewall of the Airstreaks is the winner here, with the Bushwheel coming in a bit behind it. Gar-aero's aren't in this part of the race. Gar -aero 29 X 11-10's are tall, and will roll over some stuff, but you can't expect them to deform and soak up big rocks like the Streaks will do.
If you don't intend to do SOFT virgin tundra that you don't know how soft it is, or large cobbled stones, the Gar-aero's will work great.
Beware of too low pressures, and own a new-style digital low pressure tire gauge. Too low and you'll spin the tire on the rim and maybe shear a valve stem.
Don't buy a set of 29 X 11-10's that are 10 ply. They're much heavier in weight AND construction, and are very stiff, carcass-wise. I don't want to start a whole new fight here, but as far as I'm concerned, the 26 inch Goodyear "tundra" tire is much too heavy construction-wise as well. I don't think it any better than an 8.50 X 6.00 size-wise. You can still get 4 ply 8.50's, but the 26 Goodyear isn't much taller, and you have to haul around a stiff and heavier 6 ply. Yeah, they look OK, but they're really a tire for a 180/185, when you consider the construction.
If you're worried about the toughness of the Gar-aero's, don't be. As long as you don't run them in large rocks (over grapefruit-size) at very low pressures they're fine.
Also, I've got numerous customers running them on 180/185's and 206's.
The only broken ones I've seen came off a heavily-loaded 185 running too low pressures on too large of rock size. Plenty of Cessna's are mounted up on these things.
OK, let the 26-er's unite, and throw some grapefruit size somethin' or other at me.
Dave Calkins.