Okay, we've made of a lot of fat bike related posts on here recently, so we're declaring a week long moratorium* of sorts...after this post.
It all started a few years ago with the 65mm Large Marge rim (the fat bike craze, not these posts), and the stakes were raised more recently with Darryl 80mm rims. Now Surly has come out with the outrageously wide 100mm Clown Shoe rims. These are the rims that come stock on the new Moonlander.
If you have an existing fat bike (if you got one from us you're likely riding a Pugsley or a Mukluk) and you don't want to spring for a whole new ride just to accommodate the larger rims you may be able to use them with your existing bike.
First the bad news: They will not work in the rear end of a Pugsley because the seat stays just aren't far enough apart. Well, that may not be entirely true if you wanted to run the Clown Shoes with something smaller than a Big Fat Larry (like, say, an Endomorph or a Nate), but you'd still have a problem because the Pugsley rear end is offset. Yes, the Clown Shoe is drilled to be laced offset as well, but to a different dimension than the Pugsley (16mm vs. 24mm, or something like that) so you're just out of luck there.
Up front you could accommodate the Clown Shoes on a Pugsley by setting the bike up with a Moonlander fork. That fork is centred (ie. non-offset) and the Clown Shoe rims are drilled to also be laced without a dish, so that set up will work fine, and will accommodate any tire you'd like.
Compatibility with the Mukluk is more of a guess to us at this point. It looks like the stock Mukluk front fork should be able to accommodate the larger width of a Clown Shoe rim and a Big Fat Larry (the widest overall combo available at the moment), and because the Mukluk fork is not offset it is compatible with the Clown Shoe in that regard, but until we build a wheel like that up for the Mukluk we won't know for sure. Yes, we could take some width measurements but we never trust exactly how the tire is going to seat on the rim, what rim and tube flex will do when the bike is actually ridden, and how much gunk will stick to the tires and be a problem clearing the frame or fork even if the rubber technically fits. Of course even if the Mukluk's front end doesn't accommodate the larger rim and largest tire (and we think it might) you can always stick a Moonlander fork on the from to work with the larger wheel combo just like we suggested for the Pugsley above.
We can say without a doubt that the Clown Shoe will work in the Mukluk fork with a 3.7 inch wide tire such as a Larry or Nate because (and follow this closely) a Clown Shoe with a 3.7 inch wide tire is very close to the same net maximum width as an 80mm rim (such as the stock Darryl) with a 4.7 inch tire (such as the Big Fat Larry), and we've run a Darryl/Big Fat Larry combo up front on a Mukluk with no problem. Why would you want to run a Clown Show and Larry instead of a Darryl and a Big Fat Larry if the net width is pretty much the same? Because with a wider rim width the tire sits differently and with low pressure it provides more traction because it flattens out more, even though it clears the fork with pretty much the same width. This is especially applicable if you want to run Nates or Black Floyds, which only come in a 3.7 or so width (as opposed to the Larry / Big Fat Larry, where you have the option of two tire widths with the same tread pattern). The only way to effectively make the Nates or Black Floyds 'wider' is to increase the rim width.
Finally, it looks like there's a chance the Clown Show / Big Fat Larry combo will even fit in the rear of the Mukluk (the larger rim with a Larry or other 3.7 inch tire will fit for sure), and this is helped by the non-offset nature of the rear of the Mukluk (compared with the Puglsey) BUT for some not satisfactorily answered reason the Mukluk actually comes stock with minor chain rub issues which will only be emphasized with a larger rim, tire, or both, so think about that before you decide to beef up the rear. There are ways to compensate, but you'll want to talk to us or do your own research first.
So there you have it, sort of. Hope it's more helpful than it is confusing.
*the moratorium will last a full week unless something new fat bike related unexpectedly shows up in the shop before then.