Proof that there's nothing new under the sun, this radical downhill bike was decades ahead of the trend for longer, lower, and slacker geometry.
Boulder Bicycles prototype from 1991
Asked when the trend for longer, lower, slacker geometry started, most of us would say around 2012/2013 when Mondraker introduced prototype DH and enduro models with what turned into Forward Geometry. A concept dreamt up by the likes of Cesar Rojo and Fabien Barel, then developed further by Chris Porter of Mojo/Geometron fame, as well as Finnish brand Pole. But digging back into the archive on the MBR group chat unearthed this innovative prototype from the pages of Mountain Bike Action magazine. It was built by US brand Boulder Bicycles to race the legendary Mammoth Kamikaze, a flat-out fireroad blast where chainrings were never smaller than 50t and speeds rarely sipped below 50mph. A place where legends such as John Tomac and Myles Rockwell cut their teeth.
The Geometron G1 took longer, lower, slacker to the next level.
At a time when most mountain bikes featured wheelbase measurements around 1,050mm, the Boulder Bicycles prototype measured a whopping 1,320mm! That’s up there with a modern Geometron G1! And yes, those are 26in wheels – the stretched wheelbase just makes them look absolutely tiny. Also clearly visible are the Dakotah Norton-spec high-rise bars, extended seat tube mast, and RockShox RS1 suspension forks boasting 49mm of travel. But this has been supplemented by an Action-Tec suspension system that sits inside the head tube and adds a further 60mm of travel. It’s difficult to put a figure on the head angle, but it looks to be extremely slack for the period, perhaps as relaxed as 65º. Considering most mountain bikes in 1991 had 70-71º head angles, this thing must have been a revelation at high speeds.
Most mountain bikes in 1991 looked like this Yeti Ultimate, with little or no suspension, and steep geometry.
Last but not least, Boulder Cycles was also pioneering with its use of a full-suspension design with the shock hidden inside the top tube of the steel frame. Most Boulder Bicycles models at this time had 50mm of rear wheel travel, so I can only guess it was the same on this prototype. So while Bold Cycles are known as the first brand to really come up with a hidden shock within the frame with its Linkin 150 and Unplugged, the similarly-named Boulder Bicycles beat them to an integrated and partially hidden shock by nearly a quarter of a century.