It's hard to find a weak spot in the 2015 GT Helion Expert Carbon Complete Mountain Bike's armor. It's got top notch materials, a revolutionary suspension platform, a great build, and for everything you get, we think the price ain't all that bad, either. The Helion Expert's frame benefits from GT's recent years of investing enormously in developing the most advanced applications of carbon fiber to the world of mountain biking. While they have a few different versions of the specific carbon types they've developed, the Helion Expert utilizes only the lightest and strongest, called FOC Ultra. FOC stands for Force Optimized Construction, which is a vague way of describing GT's complicated proprietary process of allocating carbon to various areas of the frame and aligning its fibers within fractions of millimeters of precision to achieve maximum stiffness where the frame needs it, and shed all excessive weight at the same time. The result is a chassis that has only been on the market for a few months, but has already won numerous awards for its outstanding overall performance, and it's causing a lot of frustration among GT's competitors. Helping out that performance is GT's revolutionary Independent Drivetrain suspension platform. The idea of isolating the drivetrain so that it's not affected by suspension movement is nothing new, but GT's approach is, and it works really, really well. The crankset and the rest of the drivetrain make their home entirely on the rear triangle, unlike many designs that put the crank on the mainframe and the rest of the drivetrain parts on the rear triangle. The problem with this is suspension compression that occurs with pedal force, robbing you of efficiency. It's simpler to build bikes this way indeed, the I. D. system on the Helion is complicated to look at, but it works. Sprinting or out of saddle climbing is rewarded with hardtail like efficiency, not dependent on a shock's damping, yet it's incredibly compliant, and the fron...