Fatbikes are great but one big problem with them has kept most people from buying them – Price.
For Electric Fatbikes the problem is further compounded by the fact that to build a decent Efatbike you are look at spending over a grand on batteries and a good motor & controller. For years the only viable options for fatbikes were the Surly/Pugsly/Salsa bikes that started at $1500 for a singlespeed and went up to well over $2000 for anything most people would want to ride. Then something awesome happened. Walmart started selling a sub-$200 fatbike to the masses.
The Mongoose Beast showed up over a year ago and it is still available here for a mere $189. The only problem that most people seemed to overlook was the weight of 58.4 lbs. The Beast was ‘a beast’ to ride and pedal and for all intents and purposes was useless to anyone except bike rental companies in Reno renting cool looking bikes to Burners going to Burning Man for $100 a week. The owner of Black Rock City Bikes went to Walmart and got almost 100 of these bikes at cost. The local Walmart stores simply could not sell them. It was a great idea but very poorly implemented. No sober human wanted to deal with pedaling around a 60lb bike no matter how cool it looked.
So a bike that is useless for human-powered pedaling might be pretty awesome as an ebike right? The problem is when you take a 60lb bike and then add another 30 lbs worth of battery/controller/motor suddenly you get a bike that you can’t carry up and down stairs anymore. In one sense the Beast was great because it was rated to carry 250lbs and was made from steel meaning that frame modifications were relatively easy. On the other hand riding a bike that is that heavy puts you into the lightweight scooter catagory and no longer ‘feels’ like riding a bike. I took a Stokemonkey modded Beast from Boxy Bikes for a cruise through the streets of Ithaca and it felt like a motorcycle. I can’t even imagine what it would be like taking something that heavy into the woods on single-track.
Walmart later release the relatively featherweight steel framed Dolomite Mongoose which weighed in at a mere 45lbs. It is currently available here for a mere $192 and being a 7 speed with disk brakes makes it FAR more attractive for electrification. The Dolomite has junk components and it is likely that the tubes($20), brakes($50), cassette($40), shifter($40) and derailer($50) would all have to be replaced to have a decent ebike. If you sourced those parts online for cheap you could probably have a decent donor bike for <$400 total. Add another $550 for a BBS02 and $50 for a chainring adapter you’re looking at a $1000 E-fatbike (without the battery). $1000 is the magic number for getting people to actually get motivated to build their own efatbikes.
The DK Duke
Although I’ve never seen a Duke in the flesh, I like the look. Hydroformed aluminum frame members and graceful lines combine with a relatively cheap $269 price tag. This model has some serious issues though, not the least of which is a rear V brake which I have never seen on any fat bike. The kickstand looks throwaway and the giant front chainring leads me to believe that whoever built this was overly optimistic with the gear ranges. I suspect a BBS02 with a much smaller chainring would make this bike more functional. 47.5 lbs is much better than most of the other fat bikes on the Walmart website and this bike might also be considered as a donor bike. However, it does not look like you would be able to grind down the BB on this bike and have enough clearance to mount a BBS02 without the 100mm axle upgrade.
The Dolomite and the Beast share one very important quality. Their 100mm bottom brackets can be easily ground down with an angle grinder to 68mm and still have clearance to fit a BBS02 with the stock axle. If you can grind that BB off and mount a BBS02 and not have the chain hit the tires in the granny gears then this is the cheapest option for BBS02 mounting. Although cranks with some offset might be necessary to clear the chainstays, it might be an elegant and dirt cheap solution to the problem of overpriced fatbikes.
There are a slew of other fatbikes on the Walmart website that are not appropriate for conversions mostly due to the weight or size of them. Of the three listed here the Dolomite wins hands down for weight/convenience and functionality. The Beast at Boxy Bikes is going to enjoy a new life as Larry proceeds to chop it in half and stretches it to make a 2 person stokemonkey Pedicab styled studded tire fatbike. Awesome.
We decided to buy 2 Dolomites after writing this article to add to our BBS02/fatbike arsenal and will be posting a build thread in the next couple of weeks. We were very disappointed to discover that although the website says the frame is aluminum, it is clearly steel. The prospect for conversion with this bike is high, as the bottom bracket has plenty of room on both sides and the back tire hub is really wide and offset which means having the chain clear the tire should be easy.
I’m also working on another post about building up Bikes Direct fat bikes with the BBS02 of which I’ve already make three.