Field Test: 2021 Salsa Blackthorn - Purple Singletrack Eater

Unlike the very large majority of brands, Salsa also offers an aluminum frame/shock for $2,099 USD. With the exact same geometry as the carbon models and a bit more weight, that'd make a lot of sense for riders who have a bunch of their own parts to hang off it. If you want a carbon frame/shock instead, it'll be $3,199 USD, please.

This is an all-new platform for Salsa and the front and rear triangles are actually shared between two bikes, this 140mm Blackthorn and the 165mm-travel Cassidy, with the extra travel of the latter coming via a longer stroke shock and different link and clevis components.

Salsa has ticked all the boxes with the new design, including a clever spot to strap a tube. They’re definitely not the first to do this, but the rubber scuff guard is a nice touch that makes theirs unique. There are also a bunch of places to bolt things, which isn’t a surprise given Salsa’s long history of letting you bolt anything anywhere on their frames. Up on the top tube are threaded holes for an EXP bag or K-Edge computer mount, and the ‘Three-Pack’ mounts on the downtube let you carry a bottle, pump, and maybe the kitchen sink.

There’s one more threaded hole I know you’re gonna be excited about: The Blackthorn’s bottom bracket, which is where you’ll also find a set of ISCG 05 tabs to mount a guide or taco. The routing is also internal, and on the carbon models it passes through molded-in guides within the frame to make the job easier.

There are a couple of things to talk about at the back of the bike, including its always controversial Super Boost hub spacing. Salsa says that the 12x157mm hub lets them get a short, 432mm chainstay length while still being able to fit either 29'' x 2.6'' or 27.5'' x 3.0'' tires. You know, just in case you want to ruin the bike with 3” wide tires... Please don’t. Those short chainstays are also aluminum instead of carbon, and Salsa has incorporated a whole bunch of smartly done frame protection in the spots where you need it, including a flap that keeps stones from getting lodged between the front triangle and chainstay yoke.

Salsa’s been using Dave Weagle’s Split-Pivot suspension layout for many years now, and you’ll find it on the back of the Blackthorn as well. It’s a concentric axle pivot that’s exactly what it sounds like - the pivot literally rotates around the rear axle. The rocker link drives a clevis that wraps around the seat tube and compresses a Fox Float DPX2 to deliver 140mm.

Salsa says that Split Pivot ''isolates pedaling and braking forces,” and they say that makes it ''uniquely suited'' to be able to swap out the clevis, link, and the shock so riders can transform the Blackthorn into the longer-travel, 165mm Cassidy. Of course, you’ll need a longer fork as well. Making two bikes from one frame saves them a bunch of money, too.

On the geometry front, the Blackthorn gets 64.6- and 76.5-degree head and seat angles in the slacker of the two settings. If you like to tinker and know that slacker doesn't always mean better, there's also a flip-chip that can steepen the head and seat angles by 0.3-degrees and raise the bottom bracket by just 4mm. I feel like this small of an adjustment range is only there for a bike shop to say that it's adjustable but, to be fair, Salsa is far from the only brand doing this. Of course, you could use that geo adjustment to tweak the bike to better suit your 27.5'' x 3'' tires...





Climbing

The Blackthorn looks like a lot of trail bike, both on paper and in person, not to mention that it's obvious Salsa wanted a bike that you remember for how it goes down, not up. Not a bad strategy, especially as the purple machine still manages to be relatively decent at the latter.

With the large-sized bike sporting a 490mm reach and 64.6-degree head angle (in the slack setting), this is never going to be the one that loves tight, technical uphills. It's in those moments, when balance and having to do a 579-degree turn that's also angled straight up the mountainside come together, that it feels like it has a big presence on the trail. And sometimes like it might not even fit through. But it nearly always does, especially after you realize the best approach is to swing that long front-end around the rear axle, and only then give it a squirt of watts to get up whatever is in front of you. Unlike the Giant Trance or Specialized Stumpjumper, bikes you can simply steer through most things when you get to them, the Blackthorn requires a bit more room and forethought.

As with many bikes like this, it has a lot of traction for you to use, with the rear-end seeming to offer more consistent bite than the firmer feeling machines. That'll help your cause through the tricky stuff, but it's also a relatively active bike that doesn't like those out of the saddle efforts, especially compared to the spritelier trail bikes on test. Pedal like you've got no idea what good form looks like and you'll see the suspension slightly dip in and out of its travel under you, meaning you're best off flipping the Fox shock's pedal-assist switch if your climbs are smooth and long.

Next to the Stumpjumper or Ibis Mojo, the Blackthorn is a bit more relaxed and it wants you to relax on the climbs as well. Doesn't sound like a terrible way to get to the top, does it?





Descending

While the lighter duty trail bikes feel, well, very much like trail bikes when pointed down most descents, Barney immediately lets you know that it's ready for more than that. The active rear-suspension and Fox 36 with its GRIP2 damper, along with geometry that rewards your uphill patience with downhill capabilities, sees the Blackthorn roll through sections that had a few other bikes stuttering a bit, especially when it got really rough.


The answer is always momentum, no matter what bike you're on, but especially so on something like the Blackthorn. Much like the P-Train, it's not a bike that loves slow-speeds and sprinting out of every corner like you're at a race, which means it's probably not the best for those flat, tight trails out there. Yeah, it'll do them, but it won't do them as well as the Stumpy or Ibis.

But the Blackthorn isn't really competing against the Stumpy or Ibis, is it? Instead, let's talk about how it compares to the coil-sprung Actofive P-Train, another so-called trail bike that favors the descents. While the intentions are similar, the two bikes are very dissimilar on the trail. The Salsa feels much more well-rounded and responsive to pedal inputs, giving it more life and energy when the terrain isn't tilted downwards as much as the mostly steel Actofive would prefer. In those moments, when the ride might include a bit of sketchy but mostly fun, it's the Blackthorn that I'd reach for. But if your trail rides see you sliding down all sorts of rowdy terrain or going at higher speeds more often than not, it's the descending-focused P-Train that provides more control and confidence.




The bike's 140mm of Split-Pivot suspension is as impressive as I'd expect, especially early on in its travel when the air-sprung shock feels quite slippery. Not coil-sprung slippery, mind you, but definitely more supple than the other air-sprung bikes. The middle of the travel feels more active, too, much more than an extra 5 or 10mm might provide, and there's zero clanging when you reach the end of the stroke. Bottom-out doesn't come any sooner than you'd expect, either, with the 140mm managing to balance small bump compliance with the end of the travel quite well. What I mean is that it's so active and smooth in the first third of its travel that you might expect it to reach the other end a bit too quickly, but it doesn't.

So where does that leave us with the Blackthorn? Well, it provides more confidence on scary downhills than the Giant, Ibis, and Stumpy, but that's not really a surprise given its numbers and spec. Then again, it can't quite match the P-Train when the descents get really chunky or tricky.

The Blackthorn is more Purple Trail Eater than friendly purple dinosaur, with its 160mm fork and active, forgiving rear-end letting you play enduro racer if you want. It's not troubled by high-speeds and rough ground, but that does come at the cost of a bit less enthusiasm than more traditional trail bikes when you're not doing anything dangerous. I guess the question is: How much danger are you facing on your trail rides?

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Reviews and Tech Videos Field Test Trail Bikes Salsa Salsa Blackthorn