I dutifully turned in the Jamis Dragon 650b Pro I'd been testing for my LBS a few weeks ago, and, missing the relief that front suspension brought to my wrists and shoulders, decided to give a rather odd set-up for my Salsa Mukluk a second try.
A couple months ago, I dropped a few bucks on a duplicate brake rotor, installed it on the original fat front wheel, and threw the whole deal in the front fork. This set-up is commonly referred to as fat-front (though I've resolved to come up with a more euphonious moniker -- maybe fat-head?). I think it looks wicked cool.
At the time, I gave it a go on a local trail, and was so horrified by the extra weight and slower handling that I swapped it back out after only one ride. Later, after my interval with the nicely-suspended Dragon front end, I went back to my fully-rigid Muk, and the wrist and hand stiffness returned. So, I put the fat wheel back on the front, resolving to give it a good chance this time.
After a few rides, I started to really enjoy myself. I wasn't nearly as sore as I'd been when riding the 29er front wheel in the rigid aluminum fork, and, with the deal, I gained some of the handling benefits of suspension from the big, soft tire.
The fat tire rolls over tall roots and jagged rocks that would give my 29er front wheel pause -- literally. So, when climbing, I have way fewer dead stops from hitting obstacles at awkward moments, even when handling an off-camber switchback. On sharp turns and descents, I get to trust my front tire a tremendous amount; the stock Surly Nates are heavily lugged and, of course, wide enough to save my bacon in many situations where I feared for my precious neck.
Granted, a fat tire is never going to handle as smoothly as a suspension fork, but I have a thing for trail feel; I find the constant flow of communications through my hands indispensable to safe and nimble riding (if a little exhausting after a couple hours).
When descending especially fast, straight, and rocky/rooty sections, I still get terribly blurry vision from all the jarring and bouncing, a clear disadvantage compared to a properly adjusted fork. (I try to think of this as a safety feature -- it keeps me from overdoing the speed on descents.)
The extra weight of the wheel, tire, and elephantine inner tube -- a hefty four or five pounds -- is not as much of a drag (pun intended) as I expected. A heavier front end stays down more. There are very few moments in which it bounces high off an obstacle on a steep climb and throws me off balance. Even though I'm pushing over thirty pounds up the steep New England slopes, this increased flow on the climbs means less exhaustion overall.
Another note regarding added weight: I've explained elsewhere that I believe that the body adapts to a reasonable level of weight variation on a bicycle. On the days when I feel exhausted riding the fat-front set-up, I'd be exhausted riding anything. On the days when I'm whippy on this set-up -- I'd be whippy on anything.
Finally, why fat-front and not fully fat, as the bike was designed? Simple: I don't need the extra four or five pounds on the back during the warm months. The 2.2 Maxxis Ardent on the back is rugged enough to handle most challenges, until the snow flies. I don't mind adapting to weight if it saves my wrists, but an extra five pounds to gain maybe 15% more traction? Nah. I'll just hike-a-bike a couple more super-steep pitches.
Having a dishless 29er rear wheel custom built on a special hub for a fat bike is not for everyone (and not every fat bike will accommodate it). But if you have the scratch, or the spare parts, give it a go; you may never go back to suspension forks again.
Heck, the conversations you start at the trailhead may be worth the price of entry alone.