For 2023 the mid-travel GT Sensor trail bike was overhauled, giving it a new yet familiar, and altogether more tidy look. While the GT brand’s bread and butter is still ‘affordable’ bikes, they also have some machines aimed at high-performance applications, and these days the two don’t have to be mutually exclusive.
Enter the GT Sensor Comp. It’s probably one of their bikes with the most mass appeal, landing at a good middle of the road price point in the bursting-at-the-seams ‘trail’ category.
GT’s renewed Sensor lineup has two distinct camps – carbon and aluminum. While material choice might be the most obvious difference, the two are actually very distinct bikes, with different geometry, very different travel numbers and of course different spec levels, despite being aimed at the same category. I’m not quite sure why they chose to go this route, since the name is really the only thing connecting the two bikes, but here we are. On test is the top level (of two) aluminum builds, the Sensor Comp, in a size large, coming in at $2,600.
- Suspension travel: 130mm front and rear
- Geometry: 65.6° head tube angle, 77.5° effective seat tube angle, 475mm reach (size large)
- Frame: aluminum; carbon version available
- Price: $2,600
- Buy from JensonUSA
GT Sensor frame details and geometry
The aluminum GT Sensor is not exactly setting the world on fire with radical design, and you could argue that it doesn’t need to. There’s nothing wild here; it’s pleasant but not exciting to look at, and that’s also no bad thing since it’s the type of bike that just needs to get the job done. It’s not a bad looking frame, with tubes that are presumably hydrofromed, and a relatively modern look in any color you like, so long as it’s black. The bottom end Sensor Sport is available in grey.
The Sensor Comp sports 130mm of travel out back served up by a four-bar type linkage and a 185x50mm trunnion shock. There’s a tapered head tube, boost rear hub spacing, UDH hanger, internally routed cables with big ports and tidy covers, and neat looking suspension pivots with nicely finished aluminum hardware. Keeping the paint fresh and quiet is a ribbed chainstay protector, and a plastic downtube rock guard. For hydration there are mounts for a single bottle cage and on the underside of the top tube is a gear mount for things like tube straps etc.
| Sizes (mm) | SM | MD | LG | XL |
|---|---|---|---|---|
| Seat tube length | 395 | 420 | 445 | 460 |
| Seat tube angle effective | 77.5 ° | 77.5 ° | 77.5 ° | 77.5 ° |
| Top tube horizontal | 551 | 579 | 607 | 646 |
| Top tube actual | 522 | 547 | 573 | 609 |
| Head tube angle | 65.5 ° | 65.5 ° | 65.5 ° | 65.5 ° |
| Standover | 740 | 740 | 745 | 755 |
| Head tube length | 110 | 120 | 130 | 140 |
| Wheelbase | 1176 | 1205 | 1234 | 1273 |
| Front center | 738 | 767 | 797 | 836 |
| Chainstay length | 440 | 440 | 440 | 440 |
| Bottom bracket drop | 35 | 35 | 35 | 35 |
| Bottom bracket height | 345 | 345 | 345 | 345 |
| Fork rake | 44 | 44 | 44 | 44 |
| Trail | 125 | 125 | 125 | 125 |
| Stack | 615 | 624 | 633 | 642 |
| Reach | 425 | 450 | 475 | 510 |
| Travel front | 140 | 140 | 140 | 140 |
| Travel rear | 130 | 130 | 130 | 130 |
Geometry-wise, the Sensor Comp is on the sensible side of progressive, with a 65.5º head tube angle, and a relatively steep 77.5º seat tube angle. Chainstays are 440mm across the board with a 35mm BB drop, and reach is 450mm in a medium and 475mm in a large.
GT Sensor Comp build specs
Spec is always a difficult balancing game, especially at this price point. I feel like it pays to use decent suspension, and that’s what GT has done here, speccing a Marzocchi Bomber Z2 fork and a Fox Float DPS Performance shock, both solid choices that should ride relatively well. The fork has an infinitely adjustable low speed compression/lockout and the shock has a 3-position lockout.
The SRAM SX Eagle drivetrain provides a wide gear range, but poor shifting quality. With the stock derailleur being practically impossible to set up out of the box, I opted to throw on a GX derailleur from my ‘garbage parts’ bin just to make it work. The stock crankset is Truvativ Descendant, but uses a Powerspline BB rather than DUB – another cheap spec choice, even at this price. I know from experience these don’t tend to last long on the trail.
The wheels are WTB ST i30 tubeless-ready rims on Formula hubs, wrapped in Maxxis OEM single-compound EXO casing Dissector and Minion DHF tires. Brakes are 4-piston, Tektro M745s on 180mm rotors.
Rounding out the spec package is a smattering of GT-branded finishing kit, including a 30mm rise handlebar that, combined with a relatively long 130mm head tube makes for quite a high stack. The wheels didn’t come with valves to set them up tubeless, but I threw some in from my stash so I wouldn’t have to run tubes, and it set up relatively easily.
Setup
Let’s talk about setting up the Sensor Comp. Starting with suspension, the fork has the usual pressure guide on the lowers, which is usually a good starting point. On the rear shock GT has handily placed a sticker that suggests between 11.7-13.9mm, which equates to roughly 23-28% sag which is a little less than the typical 28-33% that I might usually aim for. I found myself sitting around the 12-13mm mark. For the fork I decided to run around 90psi of pressure, a little over the recommended amount for my weight.
In terms of setting up the cockpit, things are a little more unusual. The relatively steep seat tube angle combined with the high-rise bar makes the cockpit feel a little cramped and tall for my liking. Rather than feeling ‘in’ the bike, I feel more like I’m perched on top of it, which makes for a more relaxed riding position than I would personally prefer.
Climbing
Part of GT’s marketing spiel talks about how the Sensor Comp is a low-weight trail bike. Low weight it ain’t though – and while weight isn’t the be all and end all of numbers, it’s worth talking about. When it comes to riding uphill on a 130mm trail bike, the 37lb that make up this bike do make themselves known, particularly on longer, smoother climbs such as paved and gravel roads, as extra weight tends to. The Float DPS shock does have a lockout switch however, which does help shut out some of the suspension movement that impedes climbing speed. However it just isn’t a fast bike uphill.
The Sensor comp has a very plush, active suspension feel, which gives the bike a relatively forgiving feel. On the way up the hill, that forgiving feel translates into a sluggish feeling that isn’t especially compatible with a more spirited climbing style, where acceleration feels a little muted thanks to a good amount of squat in the back end. To me feels slower than a 130mm travel bike should be.
The upside of this squat is that it is relatively grippy, and while it won’t set any speed records on the way to the top, it will crawl its way up some of the nastiest climbs, finding grip in places I wouldn’t have expected it to.
The Sensor Comp is not a bad climber, however a combination of the suspension kinematics and the slightly portly overall characteristic of the bike results in something that climbs like a bigger bike than I would expect from something with just 130mm travel.
Descending
On the way back down the hill, the Sensor Comp feels more like the short-travel bike that it is. Again, the back end feels plush and active, absorbing trail chatter fairly well, but struggles to stay composed under bigger hits. The rear suspension has a linear feel to it, similar to an FSR system, which can work well for more intermediate riders, but can be challenging to find the sweet spot where the bike doesn’t bottom out harshly under bigger drops etc.
The fork, while also not bad, has a tendency to ride high in its travel with little mid-stroke support, again resulting in the occasional harsh bottom-out event. Thankfully the Z2 uses a Fox 34 Rhythm chassis and can be tuned with volume spacers to provide more mid-stroke.
Once I had spent a little time figuring out the suspension setup, I found the Sensor Comp to be a fun, playful bike. The weight is less of a problem on descents, and it’s easy enough to move around and jump off of trail obstacles. Still it lacks the truly playful nature that I’d expect from a bike in this travel bracket. Instead it feels a little more subdued and happy to stay planted on the ground.
Both front and back suspension on the GT Sensor Comp do a good job considering the price point, but highlight the fact that the bike tends to feel more at home on flatter, smoother trails than steep and rowdy ones. This is further amplified by the tires which, because they are the OEM single-compound versions, lack the grip of their more expensive brothers and sisters, resulting in a nervous feeling on the descents where they struggle to hook up with any kind of confidence.
The Tektro 4-piston brakes perform well enough on flatter trails and in the dry, in fact exceeding expecations. However on steeper trails and in the wet, the M745s provide sub-par braking performance which, when combined with the cheap tires, is not confidence inspiring. A tire upgrade would be an affordable way to unlock a heap of extra performance from the Sensor, and perhaps bigger rotors and metallic pads would get some extra performance out of the brakes. An even better upgrade would be Shimano Deore 4-piston brakes.
Pros and cons of the GT Sensor Comp trail bike
Pros
- Affordable
- Decent quality fork
- Fit and finish feel good
Cons
- Heavy
- Cheap tires and brakes don’t inspire confidence
- Linear feeling suspension
Bottom line
Some bikes have a magical quality where they instantly feel comfortable to beginner and advanced riders alike, allowing both to push as hard as they want while still feeling confident at any speed. The GT Sensor Comp, on the other hand, has a distinctly intermediate feel to it. It’s not a bad bike, but it feels a touch unrefined and doesn’t truly inspire confidence the way some others do. Instead of willing the rider to push harder, it feels like it has a terminal velocity, beyond which the bike doesn’t feel comfortable being pushed.
I have to remember that not all bikes are built equal, and that the Sensor Comp is at an entry-level price point, but entry level price doesn’t have to mean entry level ride quality these days. Why does the aluminum bike have 10mm less travel and less aggressive geometry than the carbon-framed bike of the same name? The price is low however and product managers have to make difficult choices about spec, and it’s clear that in this case the manager opted for a better quality fork and sacrificed in the brake and drivetrain department, where I’d personally much rather see Shimano components. It’s a difficult choice to make, but I think a sensible one.
It’s easy to see why people choose to shop from direct to consumer brands where it’s easy to get more for the same money, however if you want to support your LBS, you could certainly do worse than the GT Sensor Comp, especially with some smart upgrades. That said, the bike is certainly better suited to a rider that isn’t looking to push boundaries or shred the gnar, but rather somebody who has flatter local trails and is a more recreational rider, comfortable at a more intermediate skill level. For those looking to buy something to progress on, my money is on an aluminum-framed bike from Giant.
- Price: $2,600
- Buy from JensonUSA.
