Big. Budget: A 2024 YT Jeffsy Core 2 Review – Travis Engel | The Radavist | A group of individuals who share a love of cycling and the outdoors.

Yes, Travis calls the $3,300 YT Jeffsy Core 2 “budget.” Maybe because it’s so good at so many things that the net bang/buck ratio is off the charts.

Sometimes I can’t tell if YT’s whole schtick is for real. I mean, their team of athletes is the “MOB,” and their limited-edition build options are “Uncaged.” Their branding is dotted with skulls and lightning bolts and crows and ninjas. But the vibe of the YT Jeffsy, which is positioned between their moderate-travel Izzo and long-travel Capra, seems to be a bit more tongue-in-cheek. YT is known for their extravagant launch videos, and the new 2024 Jeffsy was first introduced in a spoof of an ‘80s action-figure commercial. Four years before that, its predecessor debuted in a delightfully head-scratching video monologue by none other than Christopher Walken.

Quick Hits:

145 mm rear travel, 150 mm front
29” wheels, front and rear
34.8 lb (XXL size, without pedals)
Aluminum frame (carbon options available)
Sold consumer-direct through YT
$3,299 (discounted to $2,799 at time of writing)

However you feel about the try-hard marketing efforts of one of mountain biking’s major brands, I find YT’s irreverent presentation of the Jeffsy quite fitting. The bike is in a bit of a fenceless category, with the front travel at 150 mm and the rear a token 5 mm shorter at 145. But if done right, this category can be a lot of things for a lot of riders. Especially if it can be done for a reasonable price. And I think that’s a good place to start.

Value

I tested the $3,300 Core 2 model (discounted to $2,800 at time of writing), which I think represents the peak value in the current Jeffsy lineup. Above it, there is the $4,400 Core 3 ($3,650 at time of writing), with identical components to the Core 2, plus a full carbon frame and YT’s new down-tube storage. And being carbon, it’s also got more maintenance-friendly tube-in-tube guided internal routing. It’s no slouch in value itself, but for the majority of cost-conscious buyers, I’d argue that the Core 3 is just not worth struggling to find that extra $1,000 when the Core 2 will get you nearly the same ride quality.

Below the Core 2 is the $2,800 Core 1 ($2,380 at time of writing). And here’s where I’ll justify daring to put the word “budget” in the review of a $3,300 bike: There are a handful of compromises on the Core 1 that I think make the Core 2 a smarter long-term choice. For one thing, the Core 2 wheels use a rear hub with DT’s upgradable, reparable ratchet rings, while the Core 1 uses a more basic hub. Plus, that DT hub is specced with an XD freehub as opposed to the HG freehub on the Core 1’s Sun Ringlé wheelset. The freehub can be swapped down the road, but it’s an extra $100. Aside from a SRAM XD mountain cassette’s wider range, an XD freehub will open the door to lighter or wider-range cassettes down the road, or even to an upgrade to SRAM Transmission. There’s also a moderate boost in stopping power in the Core 2’s Code brakes. Most important, though, is the suspension. The Core 1’s RockShox Lyrik Base fork and Deluxe Select + rear shock are by no means bottom-of-the-barrel, but the Core 2’s Fox 36 fork and Float X shock not only offer better performance, they will better deliver on the Jeffsy’s enormous potential.

Geometry

Here, according to The Mountain Bike Internet, is where all of that potential is determined. Starting, of course, with the head tube angle. In the Jeffsy’s low setting, you get 65°. That’s only a half-degree slacker than the significantly shorter-travel Revel Rascal that I just reviewed. But as I said about the Rascal, bikes are more than their head angles. One thing I think played a bigger role in my Jeffsy’s downhill performance was its wheelbase. I tested the XXL which is 1,288 mm long, broken up into a 440 mm horizontal chainstay and an 848 mm front-center. When picking which size Jeffsy I would review, I was kinda between XL and XXL. But I opted for the XXL because I knew its steep effective seat tube angle would keep the cockpit feeling familiar. In the low setting, that seat angle was 78.6° on my XXL, with numbers slackening slightly down the size range … because that’s how it should be, thank you very much.

Unfortunately, YT is another brand who measures those numbers with the saddle horizontal from the head tube, not at an estimated appropriate height for each frame size. They’re not the only one, but this odd practice makes it hard to compare bikes. I’ve already rambled about this in a Dust-Up. Anyway, at least the Jeffsy’s claimed seat angles are especially steep, so although the true effective angle is slacker than YT claims when the saddle is up at a reasonable ride height, it still puts you in a pretty good place on the climbs. Really, the only reason I’m going on so long about it here is that the Jeffsy’s steep seat angle effectively shortens the seated cockpit, allowing riders like me who prioritize high-speed stability to err on the long side without the bike feeling too foreign.

The other geo number that stood out to me was the bottom-bracket drop. On a bike with this much travel, 33 mm is pretty deep, even in a low setting. But I think that’s the way flip chips ought to work on aggressive bikes like the Jeffsy. There should be one “normal” setting and one “low” setting. Until recently, it’s often been more like “normal” and “high.” I’d never ride most Treks or Giants or Santa Cruzes in their high setting because, although I like a steeper seat angle, I’m not knocking my pedals enough in those brands’ low settings to justify sacrificing stability by going high. But in the Jeffsy’s low setting, I definitely knocked some pedals.

Climbing

I did end up spending most of my time in the low setting (which is how the Jeffsy comes out of the box) because I do the majority of my climbing on fire roads where pedal strikes are rare and lockouts are valid. But when I did attack some singletrack with it in the high setting, I was struck by how motivating the Jeffsy can be on the uphill. YT just uses a Horst Link, and it seems to be configured more for traction and comfort than for efficiency and speed. But that steep seat tube does a hell of a lot to keep you from sinking into its travel in high-torque technical moments. I sought out a few rather clumsy canyon-crawl climbs, and I never felt like I was on a 35-pound enduro-adjacent aluminum YT. It’s the kind of bike that I would (and did) happily do 8k or 9k vertical feet in a day, and never feel like the bike was letting me down. Nor that I was letting it down.

What I mean is that, on shorter-travel “marathon” bikes, I sometimes feel pressured to take advantage of their efficiency and keep a quicker pace. That’s definitely not the case with the Jeffsy. It’s just a trusty mule, ready to go at my pace. Especially in that high setting, it always felt like it was just there, meeting me halfway with every pedal stroke. If I lived somewhere with chunky undulating terrain like parts of North Carolina, southwest Utah, or Tucson, Arizona, this thing would eat up the rough pedaly bits like a hungry, hungry hippo. It’s not a sprinter. It’ll just devour all the big round bumps faster than the kid sitting next to you.

But I live in southern California. We go up for a while, then we go down for a while. So, I left the flip chip in the “low” setting. Again, the seat tube angle is still plenty steep, so it didn’t feel lethargic on technical climbs. It just no longer felt like it was made for technical climbs. And for the other, smoother 80% of my hometown ascents, I just used the lockout. I imagine that will be the scenario for a lot of Jeffsy users. People who will choose a bike that’s built for rowdy, aggressive descents, but that won’t punish them every time they need to slowly maneuver through a rockfall, or get out of the saddle to stretch their legs with a few pumps. Truly big bikes can be a drag, but the Jeffsy is in it for the long haul.

Frame Details and Storage

Though the carbon Jeffsy has a press-fit bottom bracket, YT opted for threaded BSA on the alloy ones. Ya’ love to see it. Another carbon-versus-alloy debate is cable routing, and though the alloy frame doesn’t share the carbon’s fully guided lines, the rubber ferrules at each entry port actually did a good job keeping tension and keeping quiet. The chainstay protector is pretty extensive, stretching from behind the chainring, on top and bottom of the stay, and partway up the seatstay. Again, more quietness, but it won’t be the last time I mention it.

And gold star to YT for Most Improved Water Bottle Space. It wasn’t long ago that horizontal-shock bikes like these would give you no bottle. Now, the 2024 Jeffsy can fit 26 ounces. My Canyon Spectral has pretty much the same frame fundamentals, and I had to search to find a cage that didn’t grind my 20-ounce bottle against my shock. Then YT does one better with top-tube storage. I was spoiled by my roomy XL frame, but with my Wolf Tooth B-Rad extender, I was able to fit a lot of stuff under there, and barely any of it was touching the paint. For me, it made it that much easier to do those long rides with less on my back. But I think for a lot of the Jeffsy’s potential audience, it’s about going out with nothing on your back for some hot laps. And the laps were most certainly hot.

Descending

The first thing that stood out once I zeroed in on the right suspension settings was how quiet the Jeffsy is at speed. And it’s more than just the literal volume reduction from its cable- and chain-slap mitigation. I mean that the bike feels quiet. I almost didn’t want to mention that, because “it feels quiet” seems like such a weird thing to pass off as a helpful insight in a mountain bike review. But I kept noticing it because I’ve gone back and forth between a lot of bikes in the past couple months. Bikes with more travel or less travel than the Jeffsy, and bikes made of carbon, steel or aluminum. And on an aggressive bike with this much travel, I believe there’s only so much that frame material can—or should—stand out.

Modern carbon frames can benefit from thoughtful “tuning” during development through experiments in layup that keep them from feeling too laterally stiff. And though it’s more difficult to thoughtfully tune an aluminum frame’s feel, “too laterally stiff” is not a common complaint about aggressive alloy frames, at least among riders of average-to-above-average height and weight. My point is that the Jeffsy Core 2’s frame material didn’t seem to be doing anything special, good or bad. It was more in the suspension and how it managed impacts. I’d charge into a rocky section on the Jeffsy, and everything would be isolated in a way.

It was different from the REEB Steezl on which big bumps would push through the travel and then hit a stable, predictable ramp-up. But on this bike, it was more like the bumps were sort of blending together and disappearing into a soft, constant chatter. When trying to stay in control while careening through a mix of loose and embedded rocks, it had an averaging effect that made me feel a weird sort of mastery that I can only summon on my best days.

This is where I think the Core 2’s Fox suspension spec is worth the jump in price from the Core 1. Even Fox’s entry-level Grip fork damper (as opposed to their more advanced, more tunable Grip2) stays remarkably supportive while still adeptly managing high-speed impacts. And the adjustable low-speed compression gives it a taste of the good life. That blue lever may look like a lockout, and I suppose it can be, but a little clockwise nudge adds support without needing to add preload. The front end never got overwhelmed, keeping geometry poised and consistent.

Then in the rear, the Float X was updated a couple years ago to make for more free oil-flow in its Open mode. This helps it pack a big-shock feel into a mid-sized package, and no doubt played into that high-speed calmness. That capability paired well with the Jeffsy’s identity as an aggressive-leaning do-it-all mountain bike. Meaning, it stays composed when you put it in over its head, which for the Jeffsy, is pretty deep. And on a bike that can handle the climbs as dutifully as this one, that seems like everything you could want. But on a bike like this, I sometimes found myself wanting something else.

The reason I might pick a 150mm-travel bike over a 160 or 170mm is only partially for its practicality as a climber. I also want to be able to goof around with it, just maybe a bit more safely or on rougher terrain than I could my shorter-travel Spectral 125 or a Santa Cruz 5010. But the Jeffsy was stubbornly businesslike. It really just preferred to be brought up to speed, thrown into the bumps, and kept there. When I wanted to make it come alive anywhere beneath its maximum capability, it felt a bit vague. Like I was trying to jump rope on a trampoline. Part of this is the weight. I’m spoiled by riding goof-off bikes that are three pounds lighter. But that can’t be all of it. The Jeffsy is almost the same weight as the Steezl, and I found that bike quite responsive. So, as seems to happen at some point in all my reviews these days, I started playing with volume spacers.

The Jeffsy shock comes stock with a 0.2 cubic-inch spacer installed. Refreshingly, that’s the second smallest in the array of Float X spacers. Meaning, there’s a lot of room to make some significant changes. So, looking for a bit more feedback when putting my body weight into the bike, I jumped a whole three sizes and installed the 0.8 cubic-inch spacer. With a very slight drop in pressure, I found that fun-focused feel I wanted.

It didn’t suddenly turn the Jeffsy into a short-travel playbike. There were consequences, mainly that I was often leaving some travel on the table in those rough sections. I just wasn’t going fast enough to get as close to bottom-out as I think I should. But I found the bike to be a bit more lighthearted. And I could have probably split the difference in spacers and found an even more optimal setup. If you’re considering this build of the Jeffsy, I strongly recommend getting a spacer kit. I even went on a couple rides with no spacers at all, and that setup had its merits, too. It gave it more of a rock-crawler vibe, perfect for someone who wants ultimate traction and stability but isn’t hitting hard enough to blow through the travel.

That’s what I think is most remarkable about the Jeffsy package. All of its attributes perfectly reflect the platform’s versatility. Even down to the component spec. Like the Maxxis EXO+ casing tires, which are a bit more abuse-ready than standard EXO tires, but aren’t as heavy and dull-feeling as tires with DD casing. And the big 200 mm rear rotor seemed odd at first, but the stock SRAM Code R brakes are a little short on power, so I welcomed it. Then, there’s the seatpost. So, the YT Postman is not perfect. It’s got a pretty tall stack height, a confounding clamping method, and a painfully slow return speed. But on my XXL, it offers 230 mm of drop. That’s the longest house-brand post I’ve ever heard of. And the XL gets a 200, also rare in OEM spec. I can forgive the Postman’s slow return because I think the Jeffsy customer is going to appreciate travel more than speed.

That dropper is emblematic of what I think this bike is all about. It’s not concerned with the little niceties that might push it into another pricepoint, or the characteristics that might push it into another category. It’s only concerned with optimizing the most important qualities of a long-travel trail bike. Qualities like stability, versatility, and fun. If you’re a long-time big-bike fan who is as set in your ways as I am about your bike’s personality, you’ll be able to tease just about whatever personality you want out of the Jeffsy. But more impressively, this bike is a really good choice for anyone not set in their ways, and may be taking their first steps into long travel.

It used to be tempting to dive full-face-first into enduro territory if you needed a bike that would give you the experience this bike does. One that could get you comfortable at speed or in the air. One you could even take to the bike park and not get swallowed in all the braking bumps. But the Jeffsy can do all of that, and won’t complain about sometimes being your daily driver. Maybe that’s why its lightning-bolt branding is front-and-center, while somehow also staying subtle.