Apart from the name and the similar design of the frame, the new 2021 Trek Slash doesn’t have much in common with its predecessor. It’s longer, slacker and plusher. But is it also faster? We were very excited to be given the exclusive opportunity to test the bike on our race stage before its release.

In our introduction of the fastest enduro race bike on test you can’t just find our most interesting findings and our overall conclusion, but a good view on all bikes tested.

Trek SLASH 9.9 2021 | 170/160 mm | 14.7 kg in size L

The brand new 2021 Trek Slash was developed in close collaboration with Trek’s enduro racing team and other athletes. This quickly becomes clear when you look at the geometry and the suspension. However, those athletes obviously weren’t as involved in choosing the components: the Slash comes fitted with a small 180 mm brake rotor at the rear and rolls on Bontrager trail tires, which lack the grip and puncture protection needed for enduro racing. For our test, we replaced them with a set of grippy Schwalbe tires fitted to aluminium DT Swiss wheels that we swapped for the stock carbon option.

We also shortened the overly wide handlebars on the stock build from 820 mm to 780 mm. That aside, there’s not much to fault on the rest of the build. The massive RockShox ZEB suspension fork offers 170 mm travel, while on the back, the Thru Shaft Super Deluxe, uses a design developed by Trek in cooperation with RockShox and promises to respond extra sensitively. The SRAM CODE RSC brakes are there to keep your speed in check. The cockpit and seat post are supplied by Bontrager.

Added protection
Flying debris can quickly cause unsightly scratches and chips in the carbon frame. All the better that Trek have included an extra-large down tube protector.
Super special
Trek worked together with RockShox to develop a Super Deluxe with Thru Shaft technology that allows the piston rod to slide through the shock. This is claimed to reduce internal friction and allow the shock to respond more sensitively.,
Practical storage compartment
As with the Fuel EX, the new Slash finally has a storage compartment in the down tube. This is awesome and saves the hassle of taping things to the frame or carrying a backpack.
Pleasantly quiet
Even though the cables aren’t routed through sleeves and the chainstay protector isn’t that big, the Slash is very quiet – thumbs up!

Trek SLASH 9.9 2021

€ 8,499


Fork RockShox ZEB Ultimate 170 mm
Rear Shock RockShox Super Deluxe Ultimate 160 mm
Seatpost Bontrager Line Elite Dropper mm170
Brakes SRAM CODE RSC 200/180 mm
Drivetrain SRAM X01 30 (10-50)
Stem Bontrager Line Pro 40 mm
Handlebar Bontrager Line Pro, OCLV Carbon 780 (820) mm
Wheelset Bontrager Line Elite 30 OCLV Carbon
Tires Bontrager SE5/SE4 2.6"/2.4"

Technical Data

Size S M ML L XL
Weight 14.7 kg
Wheelsize 29"

We replaced both the carbon wheels and the Bontrager tires with a set of DT Swiss wheels with Schwalbe tires, for more grip and more puncture protection.
Still too slack
The seat angle has been steepened but it’s still very slack. We recommend pushing the saddle all the way forward for the climbs.
Precise but demanding
The RockShox ZEB is an excellent fork for everyone who feels the Lyrik offers too much flex and isn’t precise enough. However, it’s too much of a good thing for most riders and the added stiffness leads to quicker fatigue.
Small brake rotors paired with long descents lead to tired hands. We strongly recommend fitting larger rotors.
The Mino Link isn’t necessary on the Slash. It is too complicated to allow on-the-fly adjustment between climbs and descents and we always prefer the lower setting on the descents.

Longer, slacker, steeper – the geometry of the 2021 Trek Slash

While the previous Trek Slash had started to seem more like a long-travel trail bike in recent years, the new Slash has been brought back to full enduro. Trek have given the size large a long reach of 486 mm. The chainstays are kept short at 437 mm and the 64.1° head angle is plenty slack. In theory, you could adjust the geometry using the Minolink flip chip but since the bottom bracket isn’t that low, even in the slack position (29 mm bottom bracket drop), we didn’t make use of this option.

Size S M ML L XL
Seat tube 395 mm 420 mm 435 mm 450 mm 500 mm
Top tube 585 mm 610 mm 629 mm 649 mm 684 mm
Head tube 100 mm 100 mm 105 mm 115 mm 140 mm
Head angle 64.1° 64.1° 64.1° 64.1° 64.1°
Seat angle 75.6° 75.6° 75.6° 75.6° 75.6°
Chainstays 437 mm 437 mm 437 mm 437 mm 437 mm
BB height 345 mm 345 mm 345 mm 345 mm 345 mm
Wheelbase 1,197 mm 1,222 mm 1,243 mm 1,264 mm 1,305 mm
Reach 425 mm 450 mm 469 mm 486 mm 516 mm
Stack 621 mm 622 mm 626 mm 635 mm 658 mm
Jersey POC Resistance Jersey | Shoes Specialized 2FO | Kneeprotection POC JOINT VPD AIR KNEE

The steeper the better! With its geometry, the Slash performs best on steep descents.

Super plush – the 2021 Trek Slash on the trail

The new Trek Slash scores right from the start with its super plush and capable suspension. The rear end sensitively irons out bumps and thus delivers tons of traction. However, despite having set up the sag correctly, the suspension tends to wallow. In combination with the long front triangle and the relatively short rear end, this places you far back on the bike and you have to actively shift your weight forward when cornering. The bike does a great job of instilling you with confidence on steep terrain. When it comes to carrying as much speed as possible through a corner, its length is more of a hindrance. With all your weight at the back, the front wheel is light and therefore lacks precision, meaning you’re less likely to hit all your lines accurately.

Does it always have to be longer? Not with the Slash. If in doubt, we recommend the smaller size.

At high speed, the Slash is a force to be reckoned with thanks to its plush suspension and composed handling. Even so, there’s enough mid-stroke support to allow you to generate speed over rollers or get airborne. If you find yourself between two frame sizes, we recommend choosing the smaller frame size of the new Slash. All the better that Trek have decided to offer an intermediate M/L size with a reach of 469 mm. Paired with the super capable suspension, you’ll get a more agile but still sufficiently composed bike.

How does the Trek Slash 2021 compare to the competition?

Trek Slash or Specialized Enduro – it’s been an ongoing debate ever since Trek presented their first 29er enduro bike. At the models in this test, both brands still show room for improvement in terms of the componentry. In terms of handling, the Enduro is slightly more composed and easier to ride in general, while the Trek is more agile in tight sections. However, neither of them proved to be fast on our race track. They’ll do best in the bike park.

Differences from the standard bike

  • aluminium DT Swiss wheels
  • Schwalbe Super Gravity tires


With its capable suspension and longer geometry, the new Trek Slash is ready for the world’s roughest trails. It instils you with confidence and generates maximum traction on steep terrain – assuming you’ve upgraded the tires. On our race stage, the bike would have been able to perform better if we had had a smaller size, allowing us to carry more speed through corners. Therefore, be careful when choosing the frame size!


  • plush suspension offering lots of traction
  • practical storage compartment in the frame
  • very composed and confidence-inspiring on steep slopes


  • requires an active riding style
  • standard spec isn't race-ready
  • lack of compression adjustments on the rear

Mehr Informationen findet ihr auf trekbikes.com

The testfield

A lot more mtbs, our findings and the trends for the upcoming saison can be found in our introduction of the fastest enduro race bike on test.

All bikes in test: Canyon Strive CFR Jack Moir Edition (Click for review) | Commencal META AM 29 (Click for review) | GT Force Carbon Pro Martin Maes Edition (Click for review) | Lapierre Spicy Team (Click for review) | Nukeproof Mega 290c RS Team Edition (Click for review) | Raaw Madonna V2 FOX Factory Custom (Click for review) | Specialized S-Works Enduro Team Edition (Click for review) | Trek SLASH 9.9 2021 | Yeti SB150 Team (Click for review) | YT CAPRA Elite 29 (Click for review)

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