So it’s been three decades since GT Bicycles was THE mountain bike suspension brand of choice, with its RTS, LTS and STS designs ridden to countless race and championship wins by a star studded XC and DH roster. The new GT Sensor trail bike aims to capture some of that heritage and win a new audience. 

Check out our buyer’s guide if you’re looking for a rundown on the best mountain bikes on the market

Need to know

• 29er trail bike with a carbon front end and seat stays at alloy pricing
• LE version gets top-tier 150/140mm travel RockShox suspension components 
• Mix of SRAM X01 and GX mechanical drivetrain give great shifting
• Maxxis tyres and SRAM G2 RSC brakes enhance traction and control
• Only available in four frame size: S to XL

The all-new, lighter frame now uses carbon seatstays and sports comprehensive down tube protection

While the brand has had race success and some interesting designs since its heyday, the spotlight has definitely been shining elsewhere. Joining the PON bike family alongside Santa Cruz, Focus, Cannondale, Cervelo, Juliana, Reserve and others means new investment for GT and new bikes. That includes fresh versions of the Sensor 29er trail bike in 120mm and 140mm travel options. I’ve been riding the top spec 140mm LE version to find out if it’s a return to the glory days for the SoCal BMX born brand. 

New frame goes on a diet

The new carbon Sensor looks a lot like the old one, with flowing triangulated lines, and a classic Horst link four-bar rear end. The rocker linkage still drives a vertically mounted shock and the seat stays are now carbon not alloy. This combined with other tweaks shaves approximately 600g off the old (medium sized) frame. 

A trunnion mounted RockShox Super Deluxe Ultimate rear shock is standard kit on this LE spec bike

Both travel options use the same frame where an extra 5mm of stroke on the trunnion mounted RockShox Super Deluxe Ultimate shock boosts rear travel to 140mm on the Sensor LE. That’s teamed with a 150mm travel RockShox Lyrik Ultimate fork to give the Sensor LE more suspension muscle and slightly slacker geometry than the short travel bike, 

GT specs a SRAM X0 Eagle derailleur but lower tier GX for the shifter and chain

Limited size range

The frame also has extensive rubber armouring, internally routed cables that go through the frame, not the headset, and room for a full size bottle too. What’s missing then are XS or XXL sizes, internal frame storage and geometry adjustment. Yes, with only four sizes, and reach measurements spanning 430mm to 515mm, this creates big gaps between each size, but at least the short seat tubes open up the potential to add length and still keep a generous seat post drop. And while fettlers will miss the chance to tweak the geometry, for most riders the Sensor will be spot on as is. 

The Sensor’s carbon frame bucks the latest trend with cables routed through the frame, not the headset

With fewer sizes and a less complex frame design to contend with, that means more money for componentry. As such, you get top-tier RockShox suspension matched to cable operated SRAM X01/GX Eagle gears and premium SRAM G2 RSC brakes. GT’s choice of rubber is the increasingly – and welcome – Maxxis Minion DHF/Dissector combo. Yes, the WTB rims are basic, but they’re still tubeless ready and the adjustable stroke dropper is generously long at 170mm. In fact, the only glitches with the build kit are the SRAM rear hub with its horribly slow 18º engagement angle and the mushy dropper post lever feel. Oh, and despite the frame weight savings GT has implemented, it’s not a light bike overall at 15.3kg (33.7lb).

The Sensor Pro LE may sit in GT’s trail bike category but it runs a 150mm Lyrik up front

How it rides

The skinny high rise bar caused some “looks cheap” comments, but it’s got a great profile and is sized perfectly for the short stem, and works great with the similarly sorted geometry. The 65º head angle balanced steering nicely between stubborn and twitchy, so I could work the classic Maxxis Minion DHF front tire hard without getting caught out by under or oversteer. And it’s a similar story with the steep 77º seat angle, as it helps offset the way the bike sinks into its travel on climbs, so I didn’t have to slide onto the nose of the saddle to maintain front tyre connection on loose climbs. 

The same balance applies to the frame feel too. The broad top tube keeps the Lyrik fork accurately on track and once the freehub finally engages there’s plenty of stiffness to push power though the pedals and into the trail. It’s not crazy stiff, or wooden though, so the frame retains enough compliance to take the sting out of the fork when the RC2 damper on the Lyrik Ultimate chokes. 

Adjustable long stroke dropper posts and short seat tubes are welcome sights on the GT

Suspension is a highlight

Unsurprisingly the four-bar linkage LTS suspension delivers a typical brake and pedal neutral feel at the rear wheel. And what it lacks in initial sharpness in terms of stand up to sprint response, it throws a consistent blanket of grip over the ground. So, for every soggy moment in a sprint, payback came in the form of an unexpected rocky step cleaned, or a web of roots traversed with ease. It brings exactly that same nonchalant flow to descents and tech sections too, tracking smoothly over chatter and chunk alike. It’s also relatively easy to push deep into the shock stroke which makes popping the wheels off the ground easy too, but there’s still enough progression in the linkage that only aggressive riders will be wanting extra volume spacers. 

it had a sly habit of leaving my mates, not just eating dust, but sometimes actually lying in it

Taken together, it means that while the GT never felt blisteringly quick it had a sly habit of leaving my mates, not just eating dust, but sometimes actually lying in it, as the Sensor made easy work of the trickiest sections. The relaxed baseline can also be subtly but significantly altered via the low-speed compression adjuster on the Ultimate spec Super Deluxe rear shock. Adding compression let me crisp up the pedalling response and give more support under cornering when I wanted to hustle the Sensor harder. Flicking the side lever on the damper gives a full firm setting for grunting up road transfers too.

A high rise bar and plenty of headset spacers allow you to tune the fit

Now, the cheap SRAM rear hub also plays a big part in the back end feel. On the plus side the big gaps between connections mean less chance of pedal kick back off a big drop or flat landing. The downside is that the age it takes to engage can combine with the softer suspension feel, and to be a lazy, clanking frustration through stop/start techy sections. There’s plenty of headroom in the price to add upgrades though and switching to Reserve carbon wheels with Industry Nine hubs for some of the test period immediately created a much more reactive and responsive ride.

There’s no faulting the rest of the kit though. And with so many bikes defaulting to wireless SRAM shifting it was refreshing to remember how clean and fast cable operated Eagle can feel. The G2 RSC brakes are powerful enough too, consistently communicative and easy to dial preferred reach and bite point positions too. And while more aggressive/clumsy riders may want a tougher rear tyre casing, the relatively fast rolling EXO spec Dissector helps hide the Sensor’s weight when you’re pedalling all day long. Detailing aspects like the seat and chainstay protection, down tube armour, silent damping on the fork and extra supple trunnion shock stroke initiation all add to the quality package feel too.