The Fat Boy has been part of the Harley-Davidson family for over thirty years now and it’s been a chrome-laden cruiser for most of its life. However, proving that the Fat Boy can rock the sinister charm too, custom bikemaker Box 39 has converted it into an all-black monstrosity that looks ready for starring in the next Batman movie.

Custom Harley-Davidson Fat Boy By Box 39

Dubbed the Fat Box, the build began from the down low with stock solid wheels making way for massive 18-inchers. The new wheels are solid too but have a dapper black and silver finish to amp up things. The new wheels also meant the stock fenders were no good, so Box 39 proceeded to partner the wheels with custom-made front and rear fenders. In case you’re wondering, the front wheel has a 160-section tire while the rear proudly redefines “fat” with its humongous 280-section unit.

Like the wheels, everything - headlight nacelle, suspension, engine, and the tank - is gloss black with barely any chrome left, giving it a properly sinister look. Meanwhile, to further enhance the looks, Box 39 swapped the stock rear suspension with a pneumatic unit, which lowers the stance of this beast. The chassis and front suspension remain as it is, though.

With the appeal spruced up, the bikemaker went on to tweak other aspects of the bike. For starters, a flat, all-black handlebar replaces the stock, swirly unit. This, coupled with the custom footrests and seat, ensures a more aggressive riding posture.

Finally, everything comes together with an array of engine mods. Things are no longer “stock” as the Fat Box boasts a Screamin’ Eagle Stage Four engine kit which bumps the cubic capacity from 1868cc to 2146cc. Not to mention, you also get a full-system exhaust and an aftermarket belt-pulley system to round things off.

Other little updates on the build include a custom filter cover, brawny radiator guard, and handlebar-mounted mirrors, while the levers, switchgear, and instrument console remain bone-stock.

Can You Buy It?

Sadly, there’s no news on whether the Fat Box is up for grabs. But what we do know is that this is one staggering build and there’s a high chance someone’s already taken it home.