Field Test: GT Sensor Carbon Expert

Give the Sensor Carbon Expert a walk-around and it's apparent that you are getting a hell of a lot of bike for under four grand. Start with 29-inch wheels and add a 12-speed Eagle XO1/GX drivetrain, a 130-millimeter RockShox Revelation RC fork, paired with a Deluxe RT3 damper. The handlebars are wide and the cockpit is steep in the back and slack up front - which is a good thing. GT's shock-mount flip chip can be used to toggle between a 65.5 and a 66-degree head-tube angle, with a corresponding shift at the seat tube angle. We left ours in the low, slack position, 'cause that's how we like our trail bikes..





Climbing

Judging from the Sensor Expert's build, 29-inch wheels and modern numbers, I expected it to roll smoothly over the area's ceaseless roots and be calm at the controls. Instead, GT's take on the trail bike pedals and rides almost as firmly as I'd expect from an XC racer. A steep seat tube angle and zealous support from the rear suspension eliminated any settling while climbing. With or without employing the shock's low-speed compression lever, I could hammer on the pedals willy nilly and the GT would convert my effort into forward motion.

That didn't necessarily make the Sensor a great climber. Its rear end felt notchy while powering over roots, especially at slower speeds. There are many zones where high anti-squat values and mega-firm pedaling are hallowed trail bike attributes. None of those places, however, are located in the Pacific Northwest. The GT would ease into a fast tempo on the smoother sections of a climb only to bog down three meters up the next root garden. Experimenting with shock settings (like Cannondale, GT recommends a maximum of 25% sag at the shock) did little to soften the rear suspension. Low tire pressures (21 psi front and 24 rear) helped, but speed was really my only savior. Like a hardtail, the Sensor hydroplaned over the chunder as long as I stayed on the gas.

Negatives aside, the Sensor was rarely lacking for grip. Overcome your frustrations, keep the power on, and the GT could top technical sections that would raise the eyebrows of experienced observers. No doubt, some of that traction was generated by its shopping-bag-thin, tan-wall Schwalbe Nobby Nic tires which wrapped around nuances in the trail in a way that only an invertebrate life form could duplicate. More on that later.




Descending

Both riders who field-tested the Sensor Carbon commented that we were being pushed forward on the downs. The solution was to up the fork's air pressure and add a touch more low-speed compression. The culprit was that the rear suspension was riding high and overdriving the fork. Normally, the solution would be to soften the shock, but it seemed were were fighting rear suspension kinematics, not damping or spring pressure in this case. The resulting ride was still firm, but much better balanced, and the GT responded by becoming a composed descender.


GT needs to upgrade the Sensor before it's going to reach its full potential. The tan-wall Schwalbe Nobby Nic tires were a laugh. They should be renamed "El Chapo" because the air usually escaped before we had put the pump away. You didn't have to ask if I was riding the GT - the Stan's sealant on my kit was the giveaway. Another miss was the 120-millimeter-stroke seatpost on the medium-sized bike. It should have been a 150. I am only five-foot, seven inches and there was plenty of extra post showing above the clamp. Cash can fix those gaffes, but GT will need to tame the Sensor's ill-tempered rear suspension before its 130-millimeters of wheel travel will feel adequate for the aggressive trail bike category.