Hello all…just wanted to get some thoughts on something that’s been rolling around in my head. Now that it’s winter here in the northeast, I’ve been thinking about a project. I was thinking about a fat tire uni build. I’ve built wheels and have done some frame brazing so I thought now would be a good time to give it a try. Has anyone seen the Mongoose Beast Fat Tire single speed bike on the Walmart website for $160? That’s 2 wide rims (site says “alloy”, but they’re probably steel), 2 tubes and 2 tires plus a bunch of other crappy parts for $160! Granted, they are cheap and heavy, but for the price and for a winter project it may be worth a look. I believe I can also buy the needed part directly from Mongoose, but with the shipping, it may be cheaper to buy the whole bike at the local store and have some frame for fabricating. Has anyone heard such a thing?
This fat bikes has okay rims (like weinmann ones) and seems to support homemade drilling (as documented in MTBR.com forum).
However, you can forget about the tires & tubes except if you want to ride an anchor. A user from the MTBR.com forum posted the weights and you can drop 4 lbs just by swapping stock tires & tubes for Devist8or tires & regular tubes (and the Devist8or is already on the slightly heavy side with its 1850g).
Long story short, even for two rims (and two spare tubes), it can be an interesting project. If you can even re-use the spokes & nipples, its even better 
Have fun and don’t forget the final pics.
P.S.: I would be curious if the front fork couldn’t be re-used by welding UDC steel bearing caps… ? It will depend on the top inner diameter compared to available unicycle seatposts.
Fat Bike trend Dead? Walmart sells ‘Beast’ bike for $199.”
Huffing and puffing he came, dragging a 5-foot-long box up the sidewalk. My FedEx delivery man is no weakling, but he struggled with the 60+ pound package holding the Mongoose Beast, a bottom-of-the-line fat bike Walmart started selling last month.
You may have seen our preview article, “Fat Bike trend Dead? Walmart sells ‘Beast’ bike for $199.” Well, we could not resist at this price tag, and thus for less than the cost of a race saddle we held noses and put cash toward the Beast.
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I have a mongoose I got at a yard sale for 35 bucks. Just went out and it has 36 hole 4 inch wide rims that a magnet does not stick to. Its black with yellow wheels with a star on the seat and the frame up tube. It does not say Brutus or anything on it. Just mongoose on the side of the seat. The tires are little square block pattern and are like plastic/rubber. They don’t feel like regular rubber tires. The forks on this one at least are curved not straight. You could use them just might look a bit odd. look around and you might find one used. This is a single speed and quite a pig to ride on hills. Perfect gear ratio to be slow on the flats and hard on the hills. 