Back in 2017, the Trek Slash took home the Mountain Bike of the Year title during the annual Pinkbike awards. At the time, it was one of the slackest 29ers on the market, and it helped usher in the next generation of big-wheeled enduro bikes. In the years since, mountain bike geometry has undergone a significant transformation, which meant it was time for the Slash to get a revamp in order to keep up with the other contenders in this category.
The result doesn't look dramatically different from the original, but the bike now has 160mm of rear travel (10mm more than before), longer and slacker geometry numbers, in-frame storage on both carbon and aluminum models, and a threaded bottom bracket. There's also an updated, removable Knock Block that allows for a greater range of handlebar motion, eliminating a complaint some riders had about the previous version.
• Wheelsize: 29"
• Carbon or aluminum frame options
• Travel: 160mm (r) / 170mm (f)
• 64.1 or 64.6-degree head angle
• 486mm reach (size L)
• 437mm chainstays
• Weight: 32.3 lb / 14.7 kg (large 9.9 X01)
• Claimed frame weight: 2450 grams
• Price range: $3,500 - $8,500
• Frame only: $2,200 (alloy), $4,000 USD (carbon)
In total, there are seven complete builds available, two with aluminum frames and the rest in carbon. Prices start at $3,500 for the aluminum Slash 7, and go all the way up to $8,500 USD for the 9.9 XTR model.
The orange 9.9 X01 version that's pictured in this article retails for $8,000, with parts kit highlights that include a RockShox Zeb Ultimate fork, SRAM X01 12-speed drivetrain, Code RSC brakes, and Bontrager Line Elite carbon wheels. Want to spend even more? Trek offers their Project One program for certain models, which allows riders to customize the parts kit and select from a huge range of custom paint options. The full range overview can be viewed here
A whole lot, it turns out. The frame shape may be familiar, but there's a decent-sized list of updates and tweaks that were applied to the Slash.Knock Block 2.0
Trek's Knock Block system emerged when they debuted their 'Straight Shot' downtube. That straight downtube supposedly allowed for extra frame stiffness, but it also meant that the crown of the fork would smack the frame it the handlebar was turned too far, which is where Knock Block came in - a small stop chip in the headtube and a special headset top cap and stem spacers prevented the bars from turning more than 58-degrees in either direction. That wasn't an issue for some riders, but others weren't happy with the range of motion, especially on tighter switchbacks.
On the new Slash, there's 72-degrees of possible handlebar rotation, and, perhaps best of all, the Knock Block system can be completely removed. The downtube now has a slight curve in it, and the top of the fork can pass underneath without any issues. In-Frame Storage
Trek's in-frame storage solution first showed up on the Fuel EX, and now it's made its way onto the Slash as well. While Specialized deserves the credit for kicking off this trend, I'm all for it – I wouldn't mind if every bike company headed down the secret compartment path. Trek's system uses a lever that sits to the right of the water bottle cage. Flip the lever and the plastic panel can be removed, granting access to a tool roll that can be used to store a tube, CO2, and tire levers.
The in-frame storage is also found on the alloy Slash models, which means that riders at all budget levels can benefit from the ability to fill their bikes with gummy bears and small burritos. Threaded Bottom Bracket / 34.9mm Seat Tube
Adios, BB92, hello, BSA 73. To be fair, I didn't have any issues with the pressfit bottom bracket on the previous Slash, but the switch back to a threaded bottom bracket is one that's in line with what we're seeing from multiple companies. It seems to be a case of 'if it ain't broke, don't fix it' – threaded bottom brackets are less prone to creaking, and it's easier to remove and reinstall a threaded BB vs. trying to knock out a pressfit one without completely mangling it.
The Slash also has a 34.9mm seat tube diameter, and Bontrager has released a new 34.9mm version of their Line Elite dropper post that's available with up to 200mm of drop. At 5'11” I didn't have enough room to run that 200mm post without running into the kink in the bike's seat tube (the size large is spec'd with the 170mm version), but I was able to fit a 210mm OneUp dropper, which has a shorter insertion length, without any trouble. New RockShox SuperDeluxe ThruShaft
It wouldn't be a Trek without some sort of proprietary shock technology now, would it? But wait, before you start pounding on the keyboard, keep in mind that the Slash frame is compatible with a Fox Float X2 air and coil, DPX2, Super Deluxe coil, and most inline shocks.
It's the RockShox Super Deluxe Ultimate ThruShaft that's only available on the Slash, at least for now. It shares some similarities with the inline Deluxe shock, like the ability to select from three low-speed compression settings. A turn of the dial can firm up the shock for smoother, flowier trails, or turning it the other way can be useful for slippery conditions when traction is a high priority. There's also a numbered rebound knob, one of those “Why hasn't everyone been doing this?” features that should help speed up setup.
The shock uses Trek's ThruShaft design, where the damper shaft exits out the bottom of the shock, which means the damper valve assembly is moving through one column of oil. Most shocks rely on a pressurized internal floating piston to deal with the displaced oil when the shock is compressed, but with ThruShaft the shock's IFP (they refer to it as a 'thermal compensator') isn't as dynamic - it's only activated only when the oil volume increases or decreases as a result of temperature change, rather than moving every single time the shock is compressed.
The shock has a new air can, which borrows elements from RockShox's MegNeg air can, like an increased negative air spring volume. Both the negative and positive air spring can be adjusted with volume spacers – the stock setup doesn't have any spacers installed, but it's possible to add in one negative spacer or up to three positive spacers to fine-tune the feel.Geometry Updates
The Slash's head tube angle has been slackened by 1-degree, and now sits at 64.1-degrees in the low geometry setting. It's possible to steepen that to 64.6-degrees via the flip chips in the seatstays, but I have a feeling most riders will stick to the slacker setting.
Along with the slacker head angle, the bike's reach has grown by 20-30mm per size – the reach on a size large now measures 486mm. Speaking of sizes, there's now an ML option in the mix, which means there's a total of five sizes – S, M, ML, L, and XL.
The seat angle has been steepened to 75.6-degrees. That's slightly slacker than what we're seeing from other companies, especially when combined with the bike's relatively slack actual seat tube angle.
The chainstay length remains the same across the board, at 437mm in the low setting. Ride Impressions
Trek still hasn't fully embraced the steep seat-tube angle movement, and although the Slash's new numbers are a step in the right direction, the bike's 649mm top tube length gives it a very roomy feel during seated climbs. Yes, you can slide the seat forward in the rails, which is exactly what I did, but a steeper seat angle would have allowed me to keep the seat in the center, with room to move it forward or back to fine-tune the fit.
The good news is that the Slash pedals well, and the three position switch makes it easy to select your preferred amount of support. There's a full lockout, too, but I never felt the need to flip that lever. The weight's reasonable, considering we're talking about a 160 / 170mm enduro bike, and I didn't hesitate to take it out for long days of pedaling. I was a little surprised to see 175mm cranks as the stock spec - I'd rather have the extra ground clearance that comes from 170mm cranks, especially on a bike that's designed for racing.
It's on the descents that the Slash has taken a big step forward, and that's saying something considering the previous version was certainly no slouch. The 486mm reach felt familiar when descending, in line with a large Norco Sight or Commencal Meta, or an S4 Specialized Enduro, all bikes I've spent a significant amount of time aboard. The Slash has a big-bike feel that makes it easier to charge into an unfamiliar trail, while retaining enough maneuverability to prevent it from feeling like overkill on mellower trails.
It's the shock that I've been most impressed by so far – the tune feels exactly right for the bike, with a very good blend of sensitivity to smooth out the chattery bits, and support for handling bigger impacts, even without any volume spacers installed. The three compression settings make a noticeable difference, which makes it a quick process to adjust the bike to the day's conditions.
I'll be doing some head-to-head comparisons over the next few months to see how the Slash stacks up, along with putting in a bunch more miles on this orange machine – keep an eye out for a more in-depth review later this year.