2012 BH Ultralight
Perfection would almost intimate a stasis. Whatever is truly perfect would have to be the last form of an evolutionary process. We know that this is just not possible with the current pace of technological advancements. However, at the moment there are a number of bicycles that must surely be nearing the top of the pinnacle. The BH Ultralight is one of those that deserve the distinction. Its performance is only overshadowed by its contempt for the traditions of the scale. As the name would imply, the Ultralight is just that. In a painted 54cm version, the frame weighs a mere 747 grams.
Of course, light weight is nothing without performance. And who hasn't witnessed the laughable show bikes that simply aren't rideable as a normal road bike. Chris Cocalis of BH USA made the goals for the Ultralight very clear - make it the stiffest and lightest road racing frameset on the market. With a defined concept, BH was able to make the Ultralight just that by utilizing a number of key elements. These are the BB386 bottom bracket, their Formula 1 spec high modulus carbon fiber blend, and proprietary molding techniques.
You might be wondering how the bottom bracket could relate to the performance of the bike. At 86mm in width, it shares that same dimension with a standard pressfit (BB86) bottom bracket. The benefit with either is that the shell has the real estate to accommodate larger diameter down and seat tubes. As the cross-section of a tube increases, so does the torsional stiffness for any given wall thickness. The difference between the two standards has to do with the inside diameter. Where a BB86 has a 37mm ID, the BB386 has a 46mm ID. And the reason that BB386 is superior to BB86 is that it allows the use of the newer cranksets with 30mm alloy spindles. They are roughly 40-50 grams lighter than their steel spindled 24mm counterparts in addition to offering greater torsional stiffness.
The BH Ultralight is molded as a monocoque including ultra-high modulus carbon fibers. The fact that the materials meet Formula 1 specifications is not without merit. Comparatively, typical aircraft spec would be like the contrast between an Audi A6 Avant and a wood grained station wagon. The high modulus full-carbon blend afforded BH engineers the freedom to use less material to drop a significant amount of weight compared to their G5, yet still achieve the stiffness benchmarks they wanted. BH also uses a molding process that eliminates voids, wrinkles, and excess resin in the final, cured structure. And one of the nice benefits of an exacting lay-up schedule and molding process on a bike like this is that it's far removed from the wooden feel of many early composite bike frames. The result of the right amount of material and not an ounce more is a lively ride that inspires.
While the G5 uses a complex, channeled down tube to hide away the under-routed derailleur cables, the Ultralight relies on more subtle tube shapes and exposed cables. The top tube is round, and that's fine with us because a round tube can resist torsional deflection better than any other shape. Combine this with the tapered head tube and huge down tube, and you've got yourself a bike that begs to be flung into high speed sweepers or ridden no-handed down a mountain pass as you pull your rain cape from your jersey pocket. The down tube bears a softly squared shape, getting sharper as it nears the bottom bracket area. And thanks to the width of the BB386 shell, it is simply massive as is the flaring lower portion of the seat tube. The harmony at this intersection sings a song of absolute lateral stiffness, and it is a great part of what makes the bike sprint and climb as well as it does.
Like the G5, BH eliminates the need for alloy components in the frame and fork. From the dropouts to the head tube and on to the bottom bracket, their entire structures are each formed as one continuous unit. The Ultralight uses pencil-thin seatstays like the G5, but in contrast, they attach to the seat tube in a fastback style rather than a wishbone arrangement. It's a classic look, and they function in the same way to absorb road vibration so you can get to the finish line fresher and faster.