Field Test Review: 2024 Trek Slash - Rides Like a Session
PINKBIKE FIELD TEST
Trek Slash
Words by Dario DiGiulio; photography by Tom Richards
Trek Slash
Words by Dario DiGiulio; photography by Tom Richards
Trek has a careful approach to bike development, rarely taking things too far for the sake of innovation. With this year's Slash, they pushed that envelope a bit further, pulling out a lot of the more traditional stops in service of making what they see as the ideal pedal-access descent-focused bike. It certainly is a far departure from prior models, now featuring a high pivot 4-bar layout and the requisite chain accoutrement, but in many ways it's still a Trek.
The geometry is progressive without being extreme, the kinematic isn't unusual or radical, and the frame still carries typical Trek lines and accessory elements. As the bike is fairly new, you can dig into the fresher tech details in our First Ride article. This all paints a pretty rosy picture, but with a truly impressive fleet of bikes at this year's Field Test, the Slash had its work cut out for it.
The geometry is progressive without being extreme, the kinematic isn't unusual or radical, and the frame still carries typical Trek lines and accessory elements. As the bike is fairly new, you can dig into the fresher tech details in our First Ride article. This all paints a pretty rosy picture, but with a truly impressive fleet of bikes at this year's Field Test, the Slash had its work cut out for it.
Trek Slash Details
• Carbon fiber frame
• Travel: 170mm / 170mm fork
• Mixed wheel or full 29"
• 63.3° head angle
• 77° seat angle
• Reach: 432, 448, 468 (test), 488 (test), 513
• Size-specific chainstays
• Weight: 36.1 lb / 16.4 kg
• Price: $9,399 USD
• trekbikes.com
• Carbon fiber frame
• Travel: 170mm / 170mm fork
• Mixed wheel or full 29"
• 63.3° head angle
• 77° seat angle
• Reach: 432, 448, 468 (test), 488 (test), 513
• Size-specific chainstays
• Weight: 36.1 lb / 16.4 kg
• Price: $9,399 USD
• trekbikes.com
In keeping with the updates made to the Fuel EX last year, the new Slash has a ton of baked-in adjustments that can be made by the end user. Press-in headset cups allow you to slack out or steepen the head tube by 1° in either direction, a replaceable lower shock mount accommodates either a 29" or 27.5" rear wheel, with a flip chip contained therein to switch between high and low shock progression modes. All this makes for a bike that can really transform, but for the sake of this test we kept things in the mixed wheel, 63.3° head angle stock setup.
Editor's Note: You might spot a rear tire that differs from the rest of the test rubber - that was a quick flat fix done before the beauty shots were taken, but all of the riding was done with control tires fitted.
The seat angle sits around 77°, depending on the size, with chainstay length also varying to match the front end growth. Those chainstay lengths depend on whether you're running mixed or matching wheel sizes, but assuming the former the dimensions are as follows: S, 429mm; M, 429mm; M/L, 434mm; L, 434mm; XL, 439mm. Those might seem a bit short on paper, but it's important to remember that due to the high pivot layout, they grow quite a bit at sag and through the travel. At sag, the wheel is about 11mm further back, and at full extension the chainstays are a full 19mm longer than the static number. With 27mm of bottom bracket drop, the center of gravity is quite planted on the Slash, adding to the cornering stability that the growing wheelbase can provide.
Both the carbon and aluminum models get well sorted in-frame storage, in addition to some top tube bottle bosses, should you want to carry all the stuff in and on your bike.
Climbing
With 170mm of travel front and rear, it's safe to assume that climbing the Slash would be a bit of a bear, but quite a bit of work was done to make sure that it wasn't a major chore to get up to the top of your chosen descent. With very consistent anti-squat across the entire gear range - hovering just above 100% at sag - the Slash climbs comfortably and consistently, offering enough support to ride high, while still absorbing bumps along the way.
There's definitely some extra drivetrain noise accompanying the idler pulley and lower chain roller, but thanks to the high tooth count on that upper idler it's not too extreme. I spent some long pedal days on the Slash, and never found myself hating the experience - it's more than happy to motor along on logging road climbs just as it's excited to rally up technical bits of trail.
We've done the monster math, and though idler bikes do appear to be a bit slower over the course of a long climb, the Slash offsets that extra drag with an even-keeled pedaling platform and good body position that keep you comfortable for the long haul.
Descending
There's a broad assumption that the bump-eating gains of a high pivot bike are won at the cost of the overall maneuverability and pep in slower terrain. There are a few exceptions to this claim, and chief among them is the new Slash. This bike can happily mow through chunky sections of trail, but is equally capable feeling when things get tight and slow, thanks in large part to the carefully-considered geometry and very predictable suspension feel.
That predictability is key to the overall versatility of the bike, as you can push into the suspension in more flowing terrain without feeling like you're losing too much energy to the rear end. This support ramps up nicely in the middle of the stroke, meaning the bike retains a soft top-end feel for excellent small bump performance and grip. The overall feel biases towards that latter end of the spectrum, which to me is what you're probably after if you're in the market for a 170mm high pivot.
Jumping feels natural and intuitive on the Slash, and though the bike might lack some of the pop of the Ibis, it still manages to feel fun and energetic on smaller side hits and natural doubles. The Trek does feel like its penchant for speed dictates some of the terrain you'll want to point it down, as it truly comes alive when you're pushing hard on seriously challenging trails.
As a whole package, the Slash is a stiff and precise feeling bike, perhaps too much so for some who want a more forgiving chassis. The one-piece carbon bar/stem combo plays a big role here, transmitting quite a bit of feedback compared to traditional cockpits, but the Bontrager Line 30 wheels are also rather stiff. The latter didn't bother me, as they held their line nicely and shirked off plenty of the hard hits and corners that the bike is keen to carry out.
Trek did a very good job making the Slash a quiet bike, then seemingly lost the plot when they specced a hard rubber chainslap protector that does little to mitigate the drivetrain noise in bumpy terrain. I replaced the stock rubber with a bit of STFU tape, and found that the bike went from clattering through successive hits to performing in near silence, making the ride all the more sweet.
Technical Report
MRP MXg Chain Guide: This innocuous seeming lower roller may have proven to be the most controversial element of the new Trek, given the issues quite a few early users had with the chain dropping off the roller during fairly normal riding scenarios. I had this happen quite a few times during testing, both in the bike park and on lower speed tech trails in the area - all to some frustration.
After reaching out to Trek and MRP, it became clear that the guide had been improperly installed from factory, with 5mm instead of the intended 7mm of spacers between the frame and the guide. 2mm didn't seem like it would make much difference to me, but after changing the spacing and taking the bike to Pemberton for a huge weekend of riding, I was unable to get the chain to drop again. The trails up there are rough, fast, and full of good chain-challenging moments, so it's possible things are fixed for good.
RockShox Vivid Ultimate Shock: In many ways the Slash feels like the showcase bike for just how well the Vivid can perform. Its dead silent operation and excellent damping suit the bike nicely, and the shock tune feels perfect for a wide swath of riding styles. With relatively simple and visual adjustment, finding a happy place in the clickers is easy and intuitive.
RockShox AXS Reverb Seatpost: The Slash has an impressively long insertion depth, but none of that was taken advantage of in speccing an AXS post, which really only wins points in the cockpit tidiness department. Additionally, the AXS posts are prone to developing sag, which ours did within the first few days of testing. You can bleed the post fairly easily, but not having to do that in the first place would be a better proposition.
Pros
+ Excellent geometry and balanced ride
+ Composed, capable, and predictable suspension
+ Climbs well for such a downhill-focused bike
+ Excels in challenging terrain
Cons
- Chassis may be too stiff for some
- Chain drop issues due to improperly spaced lower idler (fixed)
- Stock chainstay protector did very little to manage noise
The 2023 Enduro Field Test is presented Bluegrass
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Video Title: "This is why I'm binning my 5k trek!"
Video Thumbnail: *Throwing a Trek in a dumpster*
Video Content: "Yeah, my chain dropped a bunch but found out the tensioner wasn't applying proper tension, so it's probably fixed."
lol
He’s gone weapons grade these days
No.
It’s a bit shit that these guys are making a living by trying to trash a brands reputation. I would like to see any of these guys manage a brand from 0 to selling bikes and see how they go
Or would you rather this issue was glossed over?
To me, so called "influencers" are not pros. sorry (not sorry)
they should communicate that openly, get fixed bikes to the reviewers...
on it for u to race world cups
His Slash, like Vital's test Slash, had chain drop issues no matter how the tensioner was set up.
It seems like Slash's drivetrain setup is finicky at best, and non-functional at worst. I think it is very valid to be concerned about this bike, especially when you might put hundreds of miles on that drivetrain. What if wearing it out a millimeter or two at the cogs, upper guide, chainring, jockey wheels, or tensioner has the same effect?
@succulentsausage: "Don't hate the player, hate the game" is always such a cop-out.
The problem being that MTB and DH/Enduro are very very niche and finding and making the 'right' content is incredibly hard for the athletes. Even kids/people who are doing insane things, still get next to no views. A mate of mine did a video of his 7 year old daughter doing the simplest section of trail and got 5000 likes for it... You don't see pros getting numbers like that when posting WC top 20s...
Mistakes happen, I think people can deal with that. But the ownership of this issue is fully on Trek, same as the X2 issues are purely on Fox etc.
Lewis tested the bike before racing it, not at full race pace as he states in his video, he then had it at a mechanic and with the trek support folk to try and fix the issue, further testing showed that the issue was still present.
Maybe watch the video before making a guess!!!
They don't seem too embarrassed driving their super cars and other toys around their freaking estates in England!
We have full time jobs, mortgages, kids, etc. And little sympathy for someone who has some, but certainly nowhere near enough talent to stay at near the top. If they choose to try to eek out an existence with click bait YouTube stuff, hey, good luck. And if some companies want to fund part of it, great.
But don't call them 'Pros'.
Even JKW, who puts out great content, and gets support from sponsors, refers to himself as a former pro.
To go and literally say your throwing the bike in the bin and it’s garbage because you couldn’t take 5 minutes to work it out is wild. I don’t think you would see that from any legit media source.
Ah well I guess I have to accept this is what the world likes now.
I'm continually frustrated by the writers incorrectly calling single pivots like this '4-bars'.
An they usually say things like how good that is on a Trek or Orbea but pan single pivots on any 'value' bike.
You're writing technical reviews people, get the (simple) tech right!
Placing that single pivot higher does give a different segment of that arc, but it's still a perfect arc.
Also, is ABP and Split Pivot literally the same thing? I can't figure out the distinction...
So if we put on our MTB nerd hats, this is a linkage driven high single pivot with concentric blah blah blah.
But if we put on our engineer hats, this suspension is a 4-bar layout. Well, maybe an 8 bar depending on how pedantic we want to be, as you've described.
Feels good man.
I'm also running 29" wheels both end and a 180mm fork. I downsized from L on the G5 to M/L on G6. I'm 183cm with very long arms, the ape factor is real.
I am more interested in how it compares to DW bikes if anyone here has ridden both because I have ridden Top Fuel, Fuel and Session as well some other single-pivot bikes like Stumpy, Status, Spur and etc and DW link bikes are always better at climbing, IMHO
The reason I am asking - I want heavy hitting enduro bike, but that I ENJOY on the way up as much as on the way down, in fact I would sacrifice some of it's down performance to gain in climbing ability ( looking at you Revel Rail and Ibis HD6
Given that the Spec was released in 2019, kinda makes one wonder if we're pretty darn close to "peak bike".
As an owner of the current Enduro, I will say that it does suffer from lots of chaingrowth/pedal kickback in the last 40% of the stroke. This can sometimes lead to a slight "hang up" feeling on the rear wheel when smashing through chunky stuff. If they could magically clean up that chain growth without ditching the solid antisquat at 30-40% or the initially rearward axle path, it would be hard to fault that bike.
There is a bike from every year in the past decade that has these characteristics, and for quite a few years it has been Nicolai/Geometron.
Or you know, make the upper pulley wheel narrow-wide, instead of trying to do some bullshit with the guide?
This is what you get when your industry is choc full of "industrial designers" with no engineering talent.
so maybe to much risk to build function first(i dont think eminent was fuction first)
he lower idler is there only for chain wrap on the chainring - part of the problem is the electronic shifting that also flops around a lot more due to lack of cable housing pressure, so is pretty necessary.
www.pinkbike.com/photo/25482746
The only way to get zero chain growth is to run a concentric idler pivot or bb pivot.
His chain dropped and mine didn't. I think SRAM is doing something to limit the clutch tension to improve shifting and battery life.
I get what you are talking about, but for this effect, you have to use a large diameter idler that winds and unwinds the chain through significant angle to take up the distance when suspension extends (i.e in the extended state the distance is taken up by the circumference of the idler, in the compressed state where the axle moves back, that distance is unwound and is going to the extra length needed for the chain). For this small ider, you are getting maybe like 5mm total of unwound chain, and the distance increase between it and the rear wheel is much more.
Even then, you allways have the positive derailleur cage pressure, so there is no way to get rid of that, so you will never get the chainless feel.
The kickback is a whole separate issue on the top of the chain having to do with anti squat and pedal power. When pedaling, the chain tightness, and it should actually help prevent dropped chains. When coasting however, the kickback doesn't really play an effect.
That all said, a much bigger idler would run much smoother, and keeping it perfectly aligned and with a small stop over the top of the chain to keep it from bouncing off the idler would make it all more robust.
Here is a video of a non high pivot, no idler design where the rear derailleur mech does not move.
www.youtube.com/watch?v=_iRnJiSnaeU
To be more specific, yes, the idler can be used to mitigate chain growth if you make the lower chainline in line with the pivot, but the design has to follow 2 constraints - have the chainlines running through the pivot like in your pinned example, and radius between the pivot and the bottom chainline cannot grow. Neither of which is true for the Slash.
The video of the Slash does show smaller cage movement, but its not as a consequence of an innovation of the lower idler, and more so of the entire suspension platform. Also, the gear you are in will determine growth as well, because the cage has significant vertical position changes which can affect chainlines
Those are competitive price wise. This test bike is deeeeep in fancy bike territory.
Meanwhile, the Pro's seem to suggest this bike is pretty legit.
If you break it down on a cost-per-chain pivot perspective, this bike is cheap!
Someone should be looking into the T-Type clutch tension and the fact that it's not adjustable.
T-Type may just be a bad for this suspension configuration
How is the chain derailing multiple times not a dealbreaker? It absolutely would have killed the Nucleon-Supre review if it had happened there.
Because they fixed it by adding the extra 2mm of spacers that it was supposed come with.
2mm can be a long way in certain contexts.
In this instance you don't have to do anything once you've purchased the bike beyond maybe making sure your build came with the 7mm of spacers. As for bikes with too short of a dropper, that requires you having to buy (at significant cost) a new dropper.
In saying that... I do think they harp on the short dropper a little too much... any shop worth their salt that you're buying the bike from would usually happily swap the dropper out for you anyway. And also, it's a review, you can decide for yourself how much of a deal breaker the short dropper is for you or not.
But, at the same time I think it's also good that major review sites like Pinkbike call it out so that in the future, maybe the product managers will pay a little more attention to items like this.
Since then we've now moved to a 2023 Session with idler and are yet to drop a chain in 3 month riding/racing.
It's funny thought with the GT as it's hard to tell why it's dropping and indeed HOW!
The chain ends up between the chain ring and guide, but you can't actually get it out as it's not got the clearance to remove it. So is it dropping off the idler, or off the bottom end, I never worked out.
The idler is different faced for SRAM and Shimano, one is flush, the other is offset by 4-5mm. I did manage to stop ours dropping but many racers still suffer. The new Fury has an additional guide, between the ring and idler.
Happily, the 2023 Session hasn't dropped the chain at all.
Seriously, a little mud or wear and that chain is coming off, alignment be damned!
Please fix.
It appears most of the chain dropping bikes were in North America from what I can see? Possibly a full production batch with the mistake. I know my small local shop has sold 3, in a extremely rough and rocky part of the world without issue.
Could say the same for any high pivot idler, tensioner, or gearbox bike, so what you're really saying is don't worry about it
This of course isn't a hard rule, but there's clearly a reason other brands have decided to go 27.5 only for S and XS frames.
That being said, I will see myself off below threshold.
Video by rulezman
www.youtube.com/watch?v=5LxYM8IOI3Q
This has been my exact feelings for a while.
You'd think it would be pretty cheap for RS to reuse lower castings/etc for the 35mm stanchions, and normal axle, and give us maybe a 170-200mm travel "lighter" dual crown fork that it might do well.
On the flip side, doesn't DVO have a fork that is just like that... that doesn't seem to have been a huge hit?
Does it fit? Yep
Should you run one? Up to you, but the Slash is rated up to a 190mm single crown fork which is close to a dual crown and will give you a much better turning radius.
And I also feel like you're taking it way too easy on Trek for a bike that won't keep it's drivetrain on riding medium terrain.
Sure, it's fixable, but that's an inexcusable error from a company like Trek. If I NEED to change something just so it doesn't drop chains right when you leave the shop, that's a massive problem.
All the negative press they got on a bike that rides like it's a lot lighter and flat out RIPS..
That's a load of crap, if you want it perfect on a new design 1st year out then I have a bridge to sell you from London..
Jeep has these issues, Ford has em and I know several products in off road truck racing that have shit tons of minor stuff first run
As for high pivots, they give up some pedaling efficiency to get the suspension right for long travel applications. Not worth it on a shorter travel bike, and I don't need it-but worth the tradeoff for the right conditions.
Like, how many parts are on that Toyota as compared to this Trek?
Not trying to say it cannot be a running change, but it's a bit of a black eye that it needs to be even that.
@bigmeatpete420 I get that, but the design can be pretty simply modified so that isn't true. Like look at the swingarm on most any mid-pivot bike on the chainstay side, it drops so the chain has clearance. Why isn't that done here? I just don't see why that isn't solved better than too hard of rubber that makes a racket.
Like if DVO had told the reviewers they had bushing tolerance issues and sent a fixed fork.
Sure, stuff sent for test should be good out of the box, but a wheel that needs the spokes keyed up or a frame that needs some different hardware to work right is different than a broken/poorly engineered/built product.
When it’s been happening for years. Both sides sucks hard