Living/riding around 'Vegas, every time I want to do exploring, I inevitably end up trying to grind uphill in a loose gravel wash, or sliding around on golf-ball sized marbles. This is exacerbated by the fact that many of these roads are frequented by ATV/UTV's that constantly "fluff" the gravel.

So..I'm planning out my next bike build - a fat tire bike (Puglsey or similar). I've seen lots of accounts of performance in snow and sand. I guess my question is: How do the fatties perform over this loose gravelly stuff?

After finally getting to ride a Pugsley with 3.8"s on it and seeing how well it performed in all conditions, and looking at your pictures, I can say I definitely think it would be a huge step up from what you've got now. There is a climb on one of the local trails that has a rocky section similar to what's in your second picture. The Pugsley actually made that easier to climb than my regular bike even though there was ~1" of snow on the ground(Barely enough to even be on the rocks after a couple people had ridden on it. Looking at the type of gravel in your first pic, I'd guess the Pugsley would do well there too. Are those ~2.3"s on your bike now?

I have 2.35 Small Block Eights, and I love them for hard packed and more "groomed" trails. Of course I picked the worst of the worst for my pictures, just to make a point.

What's usually frustrating is that these surfaces are typically off-camber, so It's really difficult to hold a line without sliding into even worse dirt. I'm hoping fat tires will just flex and go where I point them - even if it's slow going.

Pugsley's ride really well in all conditions, and are great for "slow going." They pedal lighter than you would expect. Climbing is not the most awesome, and you have to get used to how they turn. They turn when you lean, they turn when you steer, it's a bit different each way.

once you get used to it, which doesn't take that long, and once you know they will be "slower" on flats and climbs, you will enjoy it.