GT Sensor & Sensor ST
Wheel Size: 29’’
Travel:
- Sensor: 130 mm rear / 140 mm front (Aluminum) or 140 mm rear / 150 mm front (Carbon)
- Sensor ST: 120 mm rear / 140 mm front
Geometry highlights:
- Sizes offered: S, M, L, XL
- Headtube angle: 65° (Sensor) / 65.4° (Sensor ST)
- Seat tube angle: 77° (Sensor) / 77.5° (Sensor ST)
- Reach: 480 mm (size Large)
- Chainstay length: 440 mm
Frame material:
- Sensor: Aluminum and carbon fiber versions available
- Sensor ST: Carbon fiber
Price:
- Sensor Carbon frame w/ RockShox Super Deluxe Ultimate shock: $3,500
- Complete bikes: $2,300 to $5,750
Intro
Sea Otter has wrapped up — and we’re recovering from the chaos — but we’re not done with new bike releases, because GT just launched a new Sensor and its shorter-travel sibling, the Sensor ST.
The Frame
The Sensor and Sensor ST share a frame, with the travel change coming by way of changes to the fork travel and shock stroke (more on that in a minute). It’s a Horst-link frame built around 29’’ wheels at both ends and offered in aluminum and carbon fiber versions (though the Sensor ST builds all get the carbon frame). GT says that the carbon frame is 600 grams lighter than the previous iteration, which they’ve accomplished by a combination of weight reduction in the front triangle, swapping in carbon fiber seat stays (the chainstays are still aluminum) and some other refinements here and there.
The carbon frame gets tube-in-tube internal cable routing; the aluminum version goes to internal routing as well, but uses bolt-on ports in lieu of the internal guide tubes on the carbon version. Both get ISCG-05 tabs and use a vertically-oriented 185 mm eye-to-eye trunnion shock; the stroke and thus the amount of travel produced varies by the frame version and build. The Sensor Carbon gets 140 mm of rear travel by way of a 55mm-stroke shock, paired with a 150mm-travel fork; the aluminum bike drops to a 50mm-stroke shock, for 130 mm of rear wheel travel and pairs that with a 140mm-travel fork. And then the Sensor ST shortens the shock stroke further, to 47.5 mm, for a claimed 120 mm of rear wheel travel, again with a 140mm-travel fork.
Based on those numbers, it would appear that GT is doing some slight fudging of the rear travel numbers — the aluminum Sensor getting 10 mm less travel than the carbon one with a 5 mm drop in shock stroke sounds about right, but the Sensor ST losing another 10 mm with just a 2.5 mm shock stroke change is more suspect. We’d bet on the Sensor ST having a bit more than 120 mm travel, but GT is hardly alone in doing some rounding of their stated travel numbers to hit nice, round numbers.
Anyway, both versions of the Sensor / Sensor ST frame get a UDH derailleur hanger, a threaded bottom bracket shell, and rubber guards on the chainstay and underside of the downtube. The chainstay guard appears to only really cover the top side of the stay, so it’ll be interesting to see if there’s any notable chain slap on the underside of the stay. There’s also room for a water bottle inside the front triangle across the full size range.
Fit & Geometry
GT offers the Sensor and Sensor ST in the same four sizes as the prior-generation one, Small through XL, but the reach has grown much longer — by as much as 20 mm per size — along with a slight slackening of the head tube, steepening of the seat tube, and lengthening of the chainstays. The headtube now sits at 65° on the Sensor Carbon; the Sensor ST steepens that to 65.4° by way of the shorter fork, and the Sensor Aluminum clocks in at 65.5°. The seat tube angle is now 77° for the Sensor Carbon and 77.5° on both the Aluminum and ST versions, and the chainstay length is 440 mm across the size range.
The other notable change is that the Sensor now has a much, much shorter seat tube to make room for longer-travel dropper posts for more riders, and GT has taken advantage (at least on the higher-end Sensor builds). So on that note:
The Builds
GT offers five builds on the Sensor and two on the Sensor ST, with the Sensor Sport and Sensor Comp getting the aluminum frame, and the carbon one used on the rest of the range. A Sensor Carbon frame is also available with a RockShox Super Deluxe Ultimate shock for $3,500.
- Drivetrain: Microshift Advent X
- Brakes: Tektro M275 w/ 180 mm rotors
- Fork: RockShox Recon Silver (140 mm travel)
- Shock: X-Fusion 02 Pro RL
- Wheels: WTB ST i25 rims w/ Formula hubs
- Dropper Post: TransX (S–M : 120 mm; L–XL: 130 mm)
- Drivetrain: SRAM SX
- Brakes: Tektro M745 w/ 203 mm front / 180 mm rear rotors
- Fork: Marzocchi Z2 (140 mm travel)
- Shock: Fox DPS Performance
- Wheels: WTB ST i30 rims w/ Formula hubs
- Dropper Post: GT Dropkick (S: 125 mm; M: 150 mm; L–XL: 170 mm)
- Drivetrain: SRAM SX
- Brakes: TRP Slate w/ 203 mm front / 180 mm rear rotors
- Fork: Marzocchi Z2 (150 mm travel)
- Shock: Marzocchi Bomber CR Coil
- Wheels: WTB ST i30 rims w/ Formula hubs
- Dropper Post: GT Dropkick (S: 125 mm; M: 150 mm; L–XL: 170 mm)
- Drivetrain: SRAM SX
- Brakes: SRAM Guide T w/ 180 mm rotors
- Fork: Marzocchi Z2 (140 mm travel)
- Shock: Fox DPS Performance
- Wheels: WTB ST i25 rims w/ Formula hubs
- Dropper Post: GT Dropkick (S: 125 mm; M: 150 mm; L–XL: 170 mm)
- Drivetrain: SRAM NX w/ GX rear derailleur
- Brakes: SRAM Code R w/ 200 mm front / 180 mm rear rotors
- Fork: RockShox Lyrik Select+ (150 mm travel)
- Shock: RockShox Super Deluxe Select+
- Wheels: WTB KOM Trail i30 w/ Formula hubs
- Dropper Post: TransX +Rad (S: 150 mm; M: 170 mm; L–XL: 200 mm)
- Drivetrain: SRAM NX w/ GX rear derailleur
- Brakes: SRAM G2 RSC w/ 180 mm rotors
- Fork: RockShox Pike Select+ (140 mm travel)
- Shock: RockShox Deluxe Select+
- Wheels: WTB KOM Trail i27 w/ Formula hubs
- Dropper Post: GT Dropkick (S: 125 mm; M: 150 mm; L–XL: 170 mm)
- Drivetrain: SRAM GX w/ X01 rear derailleur
- Brakes: SRAM Code RSC w/ 200 mm front / 180 mm rear rotors
- Fork: RockShox Lyrik Ultimate (150 mm travel)
- Shock: RockShox Super Deluxe Ultimate
- Wheels: WTB KOM Trail i30 rims w/ Formula front / SRAM MTH748 rear hubs
- Dropper Post: TransX +Rad (S: 150 mm; M: 170 mm; L–XL: 200 mm)
Some Questions / Things We’re Curious About
(1) How does the Sensor stack up to the modern class of mid-travel Trail bikes?
(2) And how much rear-wheel travel do the various Sensor versions have? A few millimeters one way or the other doesn’t really matter much at the end of the day but… we’re still curious.
Bottom Line (For Now)
The updates that GT has given the Sensor — as well as the addition of the Sensor ST — look like sensible tweaks to their mid-travel Trail bike, and ones that make it, on paper, a much more modern up-to-date option in the current market. The build specs are also solid values for the money, and generally do a good job of prioritizing spending money where it’ll make the most difference without going full-bling everywhere. We’ve got a Sensor ST on the way for review, so stay tuned for more to come soon.