When it comes to high-end, high-performance bicycles, most people look to materials like carbon fiber and titanium. Thanks to a technique utilized in the building of the Hypocrite gravel bike, however, aluminum can also fit the bill quite nicely.
Made by Minneapolis-based manufacturer Heavy Bikes, the Hypocrite recently turned a lot of heads at the MADE hand-built bicycle show in Portland, Oregon. Each bike's one-piece frame is custom-built utilizing partnering company Foundry Casting Systems’ "Pascal Process."
That process in turn utilizes a technique known as sand casting, in which molten metal is poured into a mold made of sand and a bonding agent such as clay.
In this case, an inert gas is then pumped into the 3D-printed bicycle frame mold, creating a positive pressure of 150 psi (10 bar). That pressure forces molten A356 aluminum into all the nooks and crannies of the mold, leaving the center hollow. Once the aluminum has cooled and hardened, the mold is broken open with a sledge hammer to remove the frame.
That frame is then T6 heat-treated, and machined. Finally, an Enve fork, stem, seatpost and handlebars are added, along with components such as Emporia GC3 Pro gravel-specific wheels and a SRAM XX Eagle drivetrain with RED eTap AXS wireless shifters.
So, what's the point?
Well, Heavy Bikes president Charlie Murray tells us that the Pascal Process results in higher-density, less porous parts than traditional aluminum casting. This boosts the metal's tensile strength, meaning that the frame can incorporate thinner, lighter walls that are just as strong as those of traditional aluminum frames.
Of course, because the frame is cast in one piece, it also doesn't have any of those ugly tube-joining welds.
The existing complete bike weighs 23 lb (10.4 kg), although that figure should hopefully drop to 21 lb (9.5 kg) once the machining process has been optimized. The company is taking orders now, and hopes to begin production by the end of the year.
If you want a Hypocrite of your own, though, expect to pay at least US$16,000. Mind you, that price does include a professional preproduction bike fit along with customized frame cutouts and engravings.
"These bikes are rideable pieces of art," says Murray.
Source: Heavy Bikes