GT’s heavily patented, and therefore still unique, i-Drive (Independent Drivetrain) suspension system was launched in the late ’90s. It was a time when many full-suspension setups had a deservedly poor reputation for inefficient pedalling and i-Drive promised to sort it out. The Sensor 3.0 has been around for a couple of years and boasts the latest incarnation of i-Drive in affordable mid-travel form.
Ride & handling: Decent handling let down by rear shock issues
We've ridden – and liked – the costlier Sensor 2.0, so it came as a surprise to find that its more affordable stablemate doesn’t quite cut the mustard. While we have reservations about the basic fork internals on both bikes – and the 3.0’s lack of a steering-stiffening Maxle axle doesn’t help matters – it’s the X-Fusion shock on the cheaper Sensor that appears to be the issue.
Oddly inconsistent rebound damping adjustment may be partly to blame, but we found our test sample fidgeting around over trail bumps. We were getting 120mm of travel, it just didn’t feel like it. It also seemed to get bogged down at higher speeds, contributing to several grounded pedal moments as we attempted to power through rough trail sections. All in all, a disappointing performance.
We want to like the Sensor 3.0. It’s a well-priced, good-looking bike with decent handling and plenty of potential. But, despite the fact that the same shock works fine on other bikes, we’re not convinced that i-Drive and the X-Fusion shock are a happy marriage. The costlier, Fox shock-equipped Sensor 2.0 makes a much better buy.
Frame & equipment: Component compromises – weighty but functional
The ‘triple triangle’ fastback seatstays of old-school GT hardtails may have gone, but the pierced top tube – complete with embossed GT logo – lives on. GT used to claim improved stiffness and strength from the triple triangle/piercing combo, but these days it’s just a design flourish that ties the latest bikes to the company’s roots.
Early i-Drives weren’t always the most elegant of bikes, but years of evolution and a hefty dose of hydroformed swoopiness have given the Sensor clean lines. The i-Drive setup is best thought of as a simple swingarm driving the down tube-mounted shock directly, and pivoting around a relatively high point just above the big chainring.
GT’s designers have isolated the transmission by pivoting the entire bottom bracket assembly in a self-contained housing below the main pivot point, then attaching it via a dog-bone linkage to the bottom of the down tube. It sound s complicated but works pretty well in practice. In a neat bit of joined-up design thinking, GT have tucked the bottom half of the seat tube behind the front end of the swingarm. Tidy, eh?
The only problem is that this design kink makes it impossible to drop the saddle all the way down on steep descents. Get the hacksaw out… or man up. With a higher than normal down tube (to accommodate the main pivot bearing) and the need to mount the shock somewhere, there’s no room left in the GT’s main triangle for a bottle mount. GT’s designers have put it in a crud-collecting position under the down tube. Best take a CamelBak instead.
Weighing in at £500 less than its Sensor 2.0 stablemate, the 3.0’s component compromises push its weight beyond the psychological 30lb (13.6kg) barrier, although there’s not much to complain about in the Shimano Deore-based transmission and GT-branded finishing kit. RockShox’s basic-but-functional Recon fork holds up the front, while an X-Fusion 02 RL shock keeps things under control at the rear.