Descending

Simon: The Blackthorn’s descending performance isn’t as black and white as its climbing performance is; it’s still good overall, but there’s a bit more to unpack.

I initially thought the Blackthorn 145 had a somewhat playful personality, but the more time I spent trying to ride it with a playful approach, the more I realized it would push back a little and preferred a less active riding style. I also didn’t completely agree with David’s take from his Flash Review that it requires a more forward weight bias than is typical in this category.

However, after lots of miles, my perspective has changed a wee bit. I tend to agree more with David now, except that I think the Blackthorn naturally puts the rider in a more forward position. I don’t think it needs to be exaggerated much. That said, I also installed a grippier Maxxis Assagai front tire (3C MaxxGrip, DD casing) to complement the DHR II I installed for the mullet setup, and not surprisingly, that made a significant improvement in front-end grip — more on tires in the Build section.

David: I’ll just clarify my take here a bit: I stand by what I wrote in the Flash Review about the Blackthorn 145 favoring a relatively forward stance to maintain front-end grip, but mostly agree with Simon that the Blackthorn 145 encourages that sort of body positioning naturally, and I didn’t feel like I was fighting the bike on that front much.

Simon: The Blackthorn 145’s suspension feels decently supple at the beginning of the stroke and gives way to a quite firm mid-stroke and considerable bottom-out resistance. I found it hard to push into the suspension when descending to get the necessary weight transfer for a smooth manual. I think it likely has to do with the slightly forward body position as well, which gave me some trouble consistently finding the sweet spot. I’m either coming up too fast and having to use some rear brake to prevent looping out, or not coming up enough and casing whatever it is I’m trying to loft over.

In tight and twisty terrain, the Blackthorn 145 feels agile and responds well to steering input from your feet to induce some oversteer. I typically prefer mixed-wheel size bikes when cornering, and while the Blackthorn comes pretty close, I’ll still take a bike like the Santa Cruz Bronson when it comes to having a riot in the corners.

To be clear, the Blackthorn is not a poor descender, but I think the firm suspension holds it back a hair. With that said, I routinely used all the suspension travel and was able to hold good speed in chunky technical terrain, but I’m curious how it would do with a coil rear shock, or perhaps an air shock with a lighter compression tune. Overall, I think the aggressive geometry and firm suspension are in a bit of a tug-of-war, and when looking solely at the geometry numbers (mainly the slack head tube angle and short chainstays), they might lead you to believe it’s more shreddy than it is.

David: I think Simon and I are mostly on the same page about what the Blackthorn 145 does (and doesn’t) do best on the way down, but I might frame some of it a little differently, given our different preferences and local terrain.

The Blackthorn 145’s suspension is on the more supportive and lively / less plush and planted end of the spectrum, and I think that contributes to its preference for a forward stance on faster, rougher bits of trail in particular. Getting too far off the back starts to compromise front-end grip and ask a lot of the rear suspension in tandem, but if you stay forward on the Blackthorn 145 and focus on getting light over bigger compressions vs. asking the bike to plow through them, the Blackthorn 145 feels very sharp and lively, while still having enough cush to offer more margin for error than shorter-travel bikes tend to.

The tradeoff is that the Blackthorn 145 doesn’t have a huge sweet spot in terms of body positioning on the way back down, especially on steeper, rougher trails. If your local trails aren’t super steep and rough, but you want a little more suspension travel than a lot of the more efficient do-it-all Trail / All-Mountain bikes out there, the more sense that combo makes — and, again, the Blackthorn 145 pedals extremely well for a 145mm-travel bike. And the Blackthorn 145 can handle burly descents, too — it’s just a bit less composed and requires a bit more precision than a lot of the more planted, stable bikes in its travel bracket.

Blackthorn 145 as a Mullet

Simon: It was immediately apparent as soon as I swung a leg over the Blackthorn 145 after setting it up as a mullet that the geometry was clearly affected by the change, even with the flip chip in the “High” position. But, I expected that given Salsa recommends running shorter 165 mm cranks and a 2.5” rear tire, which indicates to me that the flip chip doesn’t go far enough in compensating for the smaller rear wheel. Honestly, I’m not a fan of claiming mixed wheel size compatibility with the caveat that you should go out and buy a new crankset (I’ll let the tire recommendation slide since you’ll be buying a new 27.5” tire and wheel anyway).

All that is to say that, having grown a mullet, the Blackthorn 145 feels a good bit lower and slacker. I had a crank strike within the first few feet of trail, so I instantly began the game of constantly clocking the cranks to avoid bashing rocks. Besides the crank strikes, I really like how the Blackthorn 145 rides as a mullet since it picks up some common mixed-wheelsize traits like the tendency to square off corners, and an overall more playful and rowdy personality (something I found a bit lacking in the non-mullet configuration).

Descending steep trails, the slacker head angle is noticeable and appreciated, as is the increased clearance between my butt and the rear tire — I’ve buzzed my butt many times with the 29” rear wheel and haven’t done it at all with the 27.5”. On the flip side, the slacker seat tube and head tube angles make the Blackthorn 145 mullet trickier to manage when climbing steep terrain, requiring a pretty dramatic forward shift onto the nose of the saddle to keep the front wheel tracking. The Blackthorn 145 mullet reacts well to riding more aggressively and is more fun to descend on. I think it swaps its talents and becomes a slightly better descender than climber, whereas in the 29er configuration, it’s the opposite.

Overall, I think there are better options for mullets, such as the Santa Cruz Bronson. Dedicated mixed-wheel size bikes don’t have to make sacrifices like an excessively low bottom bracket that requires shorter cranks. Would I buy new cranks and run it as a mullet if I owned it? Maybe, because ultimately I think running it as mullet shifts its performance in a way that, for me, is more in line with what I’m looking for in an All-Mountain bike.

I didn’t have 165 mm length cranks to try, so I can’t say if they will reduce the crank strikes to an acceptable level. I would need to get past being annoyed about having to buy cranks, too, and I think Salsa should either give the consumer the option of 165 mm cranks, or just spec them to begin with. All things considered, if the 165 mm cranks work well, I could see myself switching back and forth between a Blackthorn 145 with 29” wheels and fast rolling tires (like the spec’d Terrevails) set up to devour high alpine miles, and one with mixed-wheels and burly tires for more aggressive riding in gnarly terrain.