We've just received BH’s new road bike, the Ultralight, for a long-term test. True to its name, the frame weighs just 807g/1.78lb on our scale (small size, with seat binder, derailleur hanger and bottle cage bolts).
Strip it down to bare carbon (with paint) and the weight comes close to BH’s claim of 747g for a 56cm. Our 54cm frame actually weighs 768g which, while slightly off claimed, is still strikingly light. “We’ve seen them as light as 725g,” Tim Jackson, BH’s US marketing manager told BikeRadar. The all-carbon 1-1-1/8 to 1-1/2in tapered fork adds a meager 279g (0.61lb) with a 200mm steerer.
Built with a mix of Shimano Dura-Ace 7900 mechanical (including 7900-C24 TL tubeless clinchers with tubes), FSA and TRP parts, the complete bike package weighs 6.31kg (13.84lb) without pedals, and costs US$8,599; with a slightly different spec — either Cole Ventoux or Mavic R-SYS SL wheels — the UK edition costs £7,999.
BH claim that weight is only part of the Ultralight’s story, though. The other, more important, attribute is the fact that it’s the stiffest frame they’ve ever produced.
“For us, as great as light weight is – and that seems to be the thing that everyone likes to hang their hat on – our hallmark, and this comes from Chris [Cocalis, president of Pivot/BH USA], whether working on Pivots or the design of the BHs, everything comes down to stiffness,” said Jackson. “It doesn’t matter how light it is if it’s flimsy and you lose all of your pedaling efficiency. This [stiffness] is key to all the bikes that Chris has his hands on.”
The tapered head tube and BB386EVO bottom bracket standard allow for a truly massive down tube
BH achieve the desired stiffness on the Ultralight through use of "proprietary Formula 1 developed carbon blends and advanced molding techniques". The frame is built using a modular monocoque construction in which the constituent parts are molded in pieces in order to achieve the desired ride characteristics – the top, head and down tubes are from a single mold to boost stiffness and strength, and so forth.
Up front, a tapered head tube and fork steerer bolster steering stiffness, both by way of the tapered design and the larger top and down tube attachments. The new Ultralight also employs the BB386EVO bottom bracket system, which allows use of an extremely wide down tube and provides a large footprint for the chainstays.
Jackson said that not only does the wide, large diameter bottom bracket design bolster stiffness, it also allows for better molding techniques to be used. “We use a newer, advanced molding technique that only two other people in the world are using,” he said. “It offers a much higher compaction. The BB386 really helps with that for the lower half of the frame, because you can get that inner mold further into the chainstays because of the larger bottom bracket area – that’s usually one of the limiters.”
The technique uses "extreme" vacuum pressure when molding and the result, according to Jackson, is BH’s stiffest frame ever. “I ride the XL in this thing, and I’m a 210lb track sprinter, and I can tell you the Ultralight is stiffer than my G5,” he said. Stay tuned to BikeRadar for a review of the BH Ultralight once we've put some miles in.
The Ultralight's seatstays are wispy, as is the trend with today’s super-light rigs