The biggest innovation on the Trek Slash is hidden inconspicuously inside the shock. Trek calls it Thru Shaft, and it’s the latest addition to Trek’s suspension technology. Although the technology is not entirely new, it has never been properly implemented on a mountain bike.

For an overview of the test fleet head to the group test: The Crème de la Crème – Nine high-end enduro bikes of 2018 in comparison

Trek Slash 9.8
160/150 mm (f/r) | 13.95 kg | € 5,499

Yes, it’s the most expensive complete Trek Slash you can buy right now. Trek has removed the 9.9 from their lineup, so the € 5,499 Trek Slash 9.8 is the bike that has to assert itself against the competition in this group test. If you’re into bling, you’ll be disappointed with the componentry of the Slash, as you’ll be looking for high-end parts in vain. Fortunately, most of the components are fully up to par regarding functionality. The SRAM GX Eagle works reliably, the wheels and tires did not show any weaknesses, and the affordable FOX 36 Performance suspension fork also performed well. Experienced riders will have to close the damping on the fork by at least one third; this will keep the fork in the top portion of the available travel and prevent it from wallowing while still remaining sensitive. The only real weakness of the Slash is the rattling of the Bontrager dropper seatpost. Before buying the bike, you should plan an upgrade of the seat post directly into your budget and have it installed before you even take the bike home.

Helmet SCOTT Vivo PLUS | Glasses 100% Speedcraft | Jersey 100% Celium Jersey | Shorts 100% Celium Jersey | Knee pads IXS Flow Knee

  The Trek Slash doesn’t need high-end components. The ride alone was enough to convince us!

The first few meters will quickly reveal the fact that the Trek Slash was not developed for hunting uphill KOMs, but for racing down mountains instead. The seating position is comfortable, but if you have longer legs, you will find yourself sat a little too far behind the rear wheel with the dropper post extended. It is worthwhile, therefore, to push the saddle completely forward. This way you can get the most out of the Slash’s pedalling efficiency and make it comfortably to the top of every trailhead. Coming back down, the Slash reveals its full potential. The rear suspension works brilliantly and impressed us with a very sensitive response and a tremendous amount of traction. No bike succeeds in tracking the trail beneath it so well while providing such a high level of feedback. The short reach (445 mm) in combination with the short chainstays (434) gives the Slash very agile handling and makes riding it child’s play. Turns require only the slightest nudge, and it will change direction in a heartbeat. The slack head angle, paired with the plush rear suspension and the large 29″ wheels, gives the Slash the necessary composure for the most demanding lines. Even less experienced riders will find themselves pushing their limits further on this bike than they previously thought possible.

The Trek Slash 9.8 in detail

Fork FOX 36 FLOAT Performance 160 mm
Rear shock RockShox Deluxe RT3 RE:Aktiv Thru Shaft 150 mm
Brakes SRAM Code R 200/180 mm
Drivetrain SRAM GX Eagle
Seatpost Bontrager Drop Line 150 mm
Stem Bontrager Line Pro 50 mm
Handlebar Bontrager Line Pro ECLV Carbon 780 mm
Tires Bontrager SE4 Team Issue 2.4″
Wheelset Bontrager Line Elite 30
Weight 13.95 kg
Price € 5,499

More a bug than a feature
The Knock Block prevents the fork from damaging the Straight Shot downtube. In everyday life, however, it’s annoying.
The Bontrager dropper seatpost not only rattles audibly, but the clamp of the remote lever also had to be re-tightened several times during our tests. We recommend immediately upgrading.
Better than expected
The FOX 36 with the more affordable Performance cartridge convinced us with very good performance. It is crucial, however, to close the damping by one third.
Der satte Hinterbau des Trek Salsh 9.8 glänzt mit seinem ansprechverhalten mit viel Traktion.
Super plush
The biggest innovation of the new Trek Slash is the ThruShaft technology on the shock. Instead of pressurizing the oil with nitrogen, a continuous rod moves down through the shock. As a result, stiction is reduced, which allows the wheel to follow the contour of the trail more easily, providing a lot more traction.

The geometry of the Trek Slash

Size S M L XL
Top tube 590 mm 605 mm 635 mm 661 mm
Head tube 100 mm 100 mm 110 mm 125 mm
Head angle 65.6° 65.6° 65.6° 65.6°
Sitzwinkel 74.1° 74.1° 74.1° 74.1°
Chainstays 433 mm 433 mm 433 mm 433 mm
BB High 352 mm 352 mm 352 mm 352 mm
Wheelbase 1171 mm 1186 mm 1219 mm 1247 mm
Reach 416 mm 431 mm 459 mm 481 mm
Stack 608 mm 608 mm 618 mm 631 mm
Das Trek Slash 9.8 ist ein wahrer Alleskönner und sichert sich den Kauftipp.


The Trek Slash 9.8 discards unnecessary bling and does just what you expect of it: it goes downhill like a bomb. The rear end works well, and in combination with the well-balanced geometry, the Slash shines in all walks of life. With this kind of handling, it secures our Best Value tip, even if you have to take into account the money you will have to spend on a new dropper seatpost.


+ rear suspension is in a class of its own
+ suitable for all skill levels
+ highly versatile


– seat angle slightly slack
– Knock Block interferes with loading into a car
– stock dropper post rattles

Value for money

For more info head to:

The test fleet

For an overview of the test fleet head to the group test: The Crème de la Crème – Nine high-end enduro bikes of 2018 in comparison

All bikes in test: Cannondale Jekyll 1 | Canyon Strive CF 9.0 | Evil The Wreckoning X01 | Kona Process 153 CR 27,5 | Merida ONE-SIXTY 8000 | Orbea Rallon M-Team | Santa Cruz Nomad 4 CC XX1 | Specialized Enduro 29 Pro

This article is from ENDURO issue #032

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Words: Photos: Christoph Bayer, Valentin Rühl