The inaugural stop of the Enduro World Series in Punta Ala, Italy, saw the debut of a number of different prototypes as riders worked to figure out what type of machine made the most sense for the event. One of those riders was GT's Dan Atherton, who showed up with a blacked-out prototype that very well might be the replacement for their current Force platform. Aside from the quote below, GT declined to comment on the new bike, but it is a safe bet to say that the 650B-wheeled rig is sporting 150 - 160mm of travel, and that it uses a revised version of GT's Independent Drivetrain suspension design that is also being tested on their prototype Fury DH bike.
|Dan has been working on a new enduro bike for a while now, and while the bike is still in the prototype stages, the decision was made to use the Enduro World Series, and many other races, to maximize feedback for development. We want to take advantage of all the different types of terrain that enduro riders experience, and will have Dan ride the prototype throughout the season to develop the perfect enduro bike. - Bill Rudell, GT PR Manager|
Evolved Independent Drivetrain
GT has long been known for their I-Drive suspension layout, referred to as 'Independent Drivetrain' on more recent models. This suspension configuration has been designed to allow for a relatively high main pivot without the drawbacks that are usually associated with it. That high pivot does well to allow the bike to swallow up hard, direct impacts thanks to the rearward axle path that it affords, but it is the bike's floating bottom bracket that lets such a design work without the massive chain growth (think tugging on the chain as the bike goes through its travel) that would usually be associated with such a layout. GT's current Independent Drivetrain does this by allowing the bottom bracket to move roughly in the same plane as the rear axle by locating it on a separate element that pivots off of the swingarm while being attached to the front triangle by a short link, essentially creating a four-bar linkage design. GT's approach has been around for awhile in two different executions, both having seen success on the race circuit and in the hands of everyday riders, and we believe we're seeing the third iteration on Dan's prototype enduro race bike pictured here.
So, how is Dan's race bike different from the 150mm travel production GT Force that his teammate, Martin Maes, rode to a fourth place finish, one higher than Atherton himself? While it does seem to employ an evolved version of GT's Independent Drivetrain, the black bike is an entirely new beast from the ground up. The bike, which has to be said looks much cleaner than the current Force platform, appears to employ a slightly lower main pivot that is roughly inline with the top of Dan's chain ring (likely either a 34 or 36 tooth ring
), and a much more compact version of their Independent Drivetrain system, likely possible thanks to the reduced chain growth from the revised main pivot. The bottom bracket still ''floats'' on a separate forged element, but the connecting link looks to have shrunk from the approximately 4'' long unit used on the Force to a smaller 1'' long piece. The main pivot now uses a captive arrangement, with the swingarm rotating between two spars that extend out from the down tube.
Although GT says that the aluminum frame is still in the prototype stage, it does sport some very clean details - hydroformed tube sections and shapely looking shock mounts - that have us believing that the production version won't stray much from what is shown here. And while you'd be hard pressed to find a rider who is a fan of the appearance of the current production Force, Dan's bike is a definite improvement visually. The cleaner suspension layout goes a long way towards that cause, and the bike also forgoes the interchangeable rear dropouts found on the current Force, likely for standard 12x142mm dropouts. Although out of view behind his XTR cranks and chain ring, a set of ISCG-05 chain guide tabs hold the bike's Shimano chain guide in place, and it is very likely that the production model will employ a direct mount front derailleur setup rather than the clamp-style found on the present Force. The bike uses a much shorter interrupted seat tube as well, although that won't present the problem it would have in the past given that the large majority of riders would be using a dropper seat post on this bike.
With a relatively tall bottom bracket height and steepish head angle that required GT to spec Cane Creek's AngleSet from the factory to correct, we took the current production Force to task a bit in our review for its dated angles. You can bet that GT didn't make that mistake with the new bike, though, and it is plain to see from the photos here that it is both slacker and lower. With the proven pedalling capabilities of their Independent Drivetrain, and updated geometry that suits today's aggressive riders, the new bike should be quite a step forward from the current Force.