Trek Supercaliber 9.8 GX mountain bike in review – the better gravel bike?

Gravel bikes are fast and off-road capable. Can the Trek Supercaliber 9.8 GX keep up in terms of versatility or even emerge as the test winner from our bike concept comparison of gravel and mountain bikes? That’s exactly what we found out for you. You can find all the details and our riding impressions here.

Get an overview of the grouptest here: Gravel vs. mountain bike – 6 models on test

Born for the cross-country race track, tested in direct comparison to the most versatile bike concepts between gravel and mountain bikes. The Trek Supercaliber 9.8 GX weighs in at 10.6 kg in size L, which is very light for a full suspension XC bike, but a tad heavy for a full suspension gravel bike. Can it shine even more with other values?

Trek Supercaliber 9.8 GX in detail

While the Supercaliber is the second full suspension concept in the test field alongside the BMC URS LT, it is the only bike that can be adjusted to the rider’s individual needs and preferences in terms of damping and spring stiffness at both the front and rear. The IsoStrut shock and the pivotless rear triangle is a unique system with 6 cm of travel. With a conventional rear suspension, the shock is a separate unit that is actuated via a linkage. With the Supercaliber, the shock body is integrated into the frame, allowing considerable weight savings. The shock and FOX Performance 32 Step-Cast suspension fork with 100 mm travel can be locked out at the touch of a button via the handlebar remote. Bitter aftertaste: with 5 cables sprouting from it, the Supercaliber has by far the most cluttered cockpit in the test field.

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In terms of ergonomics and damping, the ESI Grips Silicone Grips deserve a mention, as does the pleasant level of compliance of the 720 mm Bontrager Kovee Pro handlebar. Our testers also like the Knock Block handlebar stop, as it protects the top tube from being hit by the handlebar in the event of a crash, without impinging on your riding at all. The geometry is absolutely race-oriented. The Trek has the shortest head tube in the history of mankind which allows for a very low front end, as is often preferred by XC racers. On steep uphills, it effectively helps prevent the front from lifting and generally puts a lot of pressure on the front wheel and thus increases itstraction. Our € 5,499 test bike does away with a dropper, instead speccing the 31.6 mm Bontrager Pro carbon seat post. However, Trek also offers the Supercaliber as a build with a dropper post.

If you’re not a fan of underbiking and prefer to be prepared for anything, go gravel riding with the Trek and you’ll be just as fast in the real world.

Size	S	M	ML	L	XL	XXL
Seat tube	394 mm	419 mm	445 mm	470 mm	508 mm	546 mm
Top tube	565 mm	595 mm	610 mm	625 mm	659 mm	683 mm
Head tube	90 mm	90 mm	90 mm	90 mm	105 mm	120 mm
Head angle	69.0°	69.0°	69.0°	69.0°	69.0°	69.0°
Seat angle	70.0°	70.5°	70.5°	71.0°	71.0°	71.0°
Chainstays	430 mm	430 mm	430 mm	430 mm	430 mm	430 mm
BB Drop	53 mm	53 mm	53 mm	53 mm	53 mm	53 mm
Wheelbase	1,079 mm	1,106 mm	1,121 mm	1,136 mm	1,172 mm	1,197 mm
Reach	395 mm	425 mm	440 mm	455 mm	485 mm	505 mm
Stack	594 mm	594 mm	594 mm	594 mm	608 mm	622 mm

The Trek mountain bike on test: our riding impressions

When it comes to acceleration, the Trek charges ahead. Its direct and willing acceleration is, surprisingly, nippier and faster than the BMC Twostroke and sits only just behind the Canyon Grizl. When climbing, there’s no bobbing on the road or hardpack thanks to the lockout – instead, the bike marches light-footed and willingly uphill. On rough gravel, you should open the lockout when climbing. This allows the Trek to maintain maximum traction without diving away beneath you. The handling is also intuitive, predictable and stable on the uphills and at a slower pace. This makes it easy to navigate tight turns at low speeds. Like its electronic and wireless AXS counterparts on the BMC bikes, the SRAM GX Eagle mechanical groupset has a huge 520% range. However, in direct comparison to the electronic options, it needs higher operating forces and a bit more time for shifting. Compared to the other mechanical groupset, like Shimano GRX RX800 fitted to the Fustle Causeway TRAIL Lite and Canyon, it is, however, significantly crisper. Thanks to the generous gear range and its good traction, the Trek becomes an absolute off-road speed all-rounder. Alongside the suspension and frame compliance, the 29 x 2.20″ Bontrager XR2 Team Issue tires mounted on the in-house Bontrager Kovee Pro 30 wheels also have their share in this. Compared to the Vittoria tires on the Twostroke, they offer more immediate propulsion and less rolling resistance on hard surfaces. Compared to a gravel bike, the Trek rolls on a very competitive wheel and tire system and is even faster than the Fustle. So, all in all, a combination that absolutely works!

On the trail, the Supercaliber plays to its strengths compared to the test field and delivers a lot of safety and traction. The lack of a dropper post is less annoying on the Trek than on the BMC Twostroke. The reason for this is the slacker seat tube angle, which puts the saddle a little further back and leaves it less in the way. On very steep downhill sections, a dropper post would still be an advantage, though you’ll have to take the weight penalty into account. When exploring roots and gravel, the Trek shines with a very high level of comfort, even on rough surfaces. At the same time, it proves to be very efficient, as obstacles are easily rolled over and swallowed up by the suspension. On gravel highways, the bike feels almost bored. Here it’s a case of putting your head down, pushing on the pedals and pressing fast forward. Fortunately, this isn’t a problem at all, as you can push the Trek over the flats at 35 km/h for a while – assuming some requisite fitness. However, after some time, the lack of options to change position on the bars and your upper body acting as a brake in the wind becomes annoying.

Tuning tip: dropper post for more trail performance (of course, bar ends for more grip positions are barred by the style police).

The perfect application for the Supercaliber 9.8 GX

With a surprisingly wide range of applications, the Trek more than surprised our testers. Its range of use is as wide as with the Lauf, but is oriented quite a bit further towards off-road riding. While it loses some trail performance with its missing dropper post, it still scores with maximum traction, riding fun and the best trail performance in the test field for all skill levels. However, for touring or bikepacking, you have to come to terms with the limited bar positions. If you mainly want to get from A to B quickly off-road, there is no better concept in this group test.

Trek Supercaliber 9.8 GX conclusion

The Trek Supercaliber is the definition of an off-road speed all-rounder and readily generates speed everywhere thanks to its enormous traction and low weight. Those who mostly avoid the road and can cope with the mountain bike position will find the better concept here compared to a gravel bike. However, in terms of versatility, the Trek ultimately has to admit defeat to the Lauf concept by a narrow margin. A very strong 2nd place!

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You can find out more about at trekbikes.com

The test field

Get an overview of the grouptest here: Gravel vs. mountain bike – 6 models on test

All bikes in test: BMC Twostroke 01 ONE (Click for review) | BMC URS LT ONE (Click for review) | Canyon Grizl CF SL 8 1by (Click for review) | Fustle Causeway TRAIL Lite (Click for review) | Lauf True Grit SRAM XPLR Edition (Click for review) | Trek Supercaliber 9.8 GX

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Words: Photos: Peter Walker, Benjamin Topf