After years of anticipation, Trek is launching a completely redesigned version of its long-travel 29er, the Slash. The new bike gets the longer, slacker treatment that it's needed along with a range of other refinements that make it more competitive. Here's everything you need to know about the Trek Slash 2021.

Related: Trek Slash 9.9 Review

How does the geometry of the Trek Slash 2021 compare to the older version?

Trek Slash 2021

For the 2021 model year, the Slash gets a bump in suspension travel with 160mm at the rear and 170mm up front. (This is up from 150mm rear and 160mm front.) The Slash retains the two-position geometry adjusting Mino-Link. The head tube angle is .06-degrees slacker (high: 64.6, low: 64.1) and the seat tube angle gets almost two-degrees steeper, giving the rider a much-improved climbing position (high: 76.1, low: 75.6). Reach gets longer by 20-30mm depending on size.

Trek Slash 2021: geometry

Are there any new frame features on the Slash?

Trek Slash 2021: frame features

The larger 34.9mm diameter seat tube accommodates more robust dropper posts. The BSA 73mm threaded bottom bracket is more robust and easier to service. A full-length downtube guard provides added protection, especially for shuttling. Last but not least, all models, including alloy, come with internal frame storage.

How much dropper post insertion does the Trek Slash frame have?

Dropper post insertion is improved over the first-generation, giving riders the ability to run longer droppers across all five frame sizes.

Maximum dropper insertion per frame size:

  • S: 205mm
  • M: 230mm
  • M/L: 245mm
  • L: 260mm
  • XL: 310mm

Does the Slash still use Knock Block?

Trek Slash 2021: Knock Block

Yes. The Slash uses a new version of Knock Block, called Knock Block 2.0, to protect the top tube and cables in a crash, but the fork crown does clear the downtube, so Knock Block is removable. Thankfully, Knock Block 2.0 has an increased turning radius for improved low-speed handling.

Is Knock Block 2.0 backward compatible? Can I use the new frame chip to get a larger turning radius on bikes from previous years?

No. Knock Block 2.0 is not compatible with frames using the original Knock Block.

Related: The pros and cons of Knock Block in the Mtbr forums

Will a water bottle fit in all sizes?

Yes! All sizes will fit a water bottle in the front triangle.

How much does the Trek Slash weigh?

Weight will vary with the build. The carbon frame has a claimed weight of 2,450g. This is approximately 100g heavier than the previous version. According to Trek, this minor weight increase with the result of reinforcing the front triangle for longer-travel forks and the adding the downtube storage box.

The weight of the complete Slash 9.9 we tested is 32.5 pounds.

What is the maximum tire size on the Trek Slash?

The largest tire riders can run in the rear of the Slash is 29x2.50". Many versions come equipped with a 29x2.6" tire at the front paired with a 29x2.4" tire in the rear.

Is the Slash compatible with other wheels/tire sizes and "mullet" setups?

No. According to Trek, none of the brand's enduro racers preferred the mixed size tire combination, so it wasn't a priority when redesigning the Slash.

What is the rear brake mount? What is the max rotor size?

The rear brake uses a 180mm direct post mount. The Slash frame has a 220mm maximum rotor size.

What is the hub spacing?

A small but growing number of brands are moving to the Super Boost 12x157mm axle standard. Trek was able to retain the 148x12mm rear axle spacing with a 55mm chainline. Front axle spacing remains the same at 110x15mm.

What is the maximum chainring size? Minimum chainring size?

Maximum: 34T

Minimum: 28T

What is the maximum fork axle-to-crown and/or travel?

Spec is 571mm axle-to-crown or 170mm. The maximum is 596mm or 180mm.

In which Mino Link position does the bike ship?

The Trek Slash ships with the Mino Link in the lowest position.

Can I use a shock with a longer stroke to increase the rear travel?

No. According to Trek, this will result in damage to the seat tube or seatstays at full travel.

Is the new Super Deluxe compatible with air spring volume spacers?

Yes. The shock is tuned for the stock set-up with no volume spacers installed, but both the positive and negative air springs can be tuned with spacers. Add up to one negative air spring spacer for better small bump compliance. Add up to three positive air spring spacers for more progression/bottom-out resistance.

Is the Slash compatible with aftermarket shocks?

Yes, aftermarket shocks will fit, including:
  • - MY21 Fox X2 Coil
  • - MY21 Fox X2 Air
  • - RockShox Super Deluxe Coil
  • - Fox DPX2
  • - MRP Hazard
  • - Most inline shocks (no reservoir/piggyback)The standard RockShox Super Deluxe air shock does not fit due to lockout lever interference in the last 1/3 of the travel. The new Super Deluxe Thru Shaft uses a new shock body from RockShox that provides more clearance.

How much does the Trek Slash 2021 cost?

Trek Slash 2021: Slash 8 GX

Trek's Slash 8 GX​

Complete Bikes

  • Slash 9.9 XTR: $8,499
  • Slash 9.9 XO1: $7,999
  • Slash 9.8 GX: $5,999
  • Slash 9.8 XT: 5,999
  • Slash 9.7 NX: $4,799
  • Slash 8 GX: $3,999
  • Slash NX: $3,499
Framesets w/shocks
  • Slash Carbon Frameset: $3,999
  • Slash Alloy Frameset: $2,199
Related: Mtbr's Trek Forum