Driven by the “Power of Friendship” mantra, YT claim to have found a solution to the ongoing energy crisis with their new JEFFSY 2024. The latest incarnation of their trail evergreen is supposed to cover a wide range of applications and thus expand your circle of riding mates, while at the same time putting a big grin on your face. We’ve tested the JEFFSY CORE 5 CF for you.

YT JEFFSY CORE 5 CF | 150/145 mm (f/r) | 29” | 15,3 kg in size L | € 5,999 | Manufacturer’s Website

What’s fun to hang out with, always has your back and never lets you down, even when things get ugly? No, it’s not your best mate! It’s the new 2024 JEFFSY! With the latest iteration of their trail evergreen the Bavarian direct-to-consumer brand is taking the concept of trail bike to a whole new level. The new JEFFSY combines 150/145 mm of travel with a pair of 29″ wheels, which are bolted to a full carbon frame. As usual, YT also offer a couple of alloy variants, but more on this later. Our YT JEFFSY CORE 5 CF 2024 test bike in size L tips the scales at 15.3 kg and retails at € 5,999.

The new 2024 YT JEFFSY CORE 5 CF in detail

At first glance, the new 2024 YT JEFFSY doesn’t look much different from its predecessor, relying on the same rear suspension design with a horizontally mounted shock, which merges seamlessly into the seat stays. In purely visual terms, YT didn’t exactly go crazy, with only subtle tweaks to the silhouette. Yet still, the design language is refreshingly modern, rounded off by a Space Blue paint finish on our CORE 5 CF test bike (or dark blue if you’re not called Elon Musk or Jeffsy Bezos). YT’s development team clearly chose evolution over revolution with the latest overhaul of the JEFFSY, which is reflected not only in the overall design of the bike but also the clever frame features, like the small storage compartment in the down tube. This is easily accessible and can be opened via a small lever, which is positioned right above the bottle cage, making it harder to activate the lever with a bottle in the cage. However, this only means that you have to remove the bottle before opening the compartment, which isn’t that big of a deal. The edges of the storage compartment are nicely rounded, preventing thin garments from ripping when you pull them out. On top of that, the compartment comes standard with two pouches for all your trail essentials, preventing the contents from rattling against the frame – and there’s still enough room for a trail banana. But that’s not all: there’s also a tool strap on the underside of the top tube, where you can carry a spare inner tube and tire levers, for example. The pouches, tool strap and tire levers are all part of the JEFFSY’s standard equipment.

Banana for scale! The storage compartment is easily accessible and comes standard with two pouches that can be used to store all your trail essentials, preventing them from rattling against the frame – and there’s still room for a snack.
You can carry even more stuff using the tool strap at the bottom of the top tube, which makes it easy to stow away a spare inner tube and tire levers.

A generously sized seat- and chainstay protector extends far over the front section of the swingarm, preventing chain slap and paint chips. The cables are routed internally and disappear into the frame through the head tube. Unfortunately, the cable ports aren’t clamped and only rely on rubber inserts, which tend to slip out of the ports – and when this happens, the cables knock against the frame. However, using a couple of small zip ties you can secure the inserts and prevent them from sliding.

The seat and chainstay protector extends far over the front section of the swingarm, preventing chain slap and paint chips.
The cables disappear into the frame through the head tube and are secured to the cable ports with small rubber plugs. However, these tend to slip out of the ports.

Tuning tip: Secure the cable port inserts with small zip ties to prevent them from rattling

The spec of our 2024 YT JEFFSY CORE 5 CF

We tested the JEFFSY CORE 5 CF flagship model, which retails for € 5,999 and offers a pretty insane price/quality ratio. For starters, you’ll get FOX Factory suspension consisting of a FOX 36 fork and matching FLOAT X air shock. Alongside the fancy Kashima coating, you’ll get FOX’s superior GRIP2 damper in the fork, which allows for countless adjustment options and delivers a tremendous performance on the trail. The shock features externally adjustable rebound and low-speed compression settings.

The 36 Factory fork features FOX’s superior GRIP2 damper delivers a tremendous performance on the trail and offers four-way adjustability with high- and low-speed control of both the rebound and compression circuit.

An electronic SRAM X0 Eagle Transmission drivetrain ensures butter-smooth, precise shifting and relies on a hangerless rear derailleur, which is bolted directly to the frame. For the controls, YT rely on a classic AXS Rocker controller rather than the new AXS pods, with a Matchmaker clamp making it easier to fine tune cockpit ergonomics.

The electronic SRAM X0 Eagle rear derailleur is extremely robust and bolted directly to the frame.
What is rather curious is that YT combine the new Transmission drivetrain with SRAM’s old AXS Rocker controller. However, in conjunction with the Matchmakers, this makes it easier to adjust the cockpit ergonomics than with the new AXS pods.

For the brakes too, YT rely on the conventional CODE RSC model rather than the new Stealth version, and pair them with 200 mm rotors front and rear. However, these deliver the same powerful braking performance and feature tool-free bite point and lever reach adjustments, as well as SRAM’s proprietary SwingLink technology, which is designed to minimise deadband and optimise modulation, thus reducing arm pump. Furthemore, the lever unit of the conventional CODE brakes isn’t positioned as close to the handlebars as the Stealth lever, meaning that the cables don’t rattle against the handlebars as easily.

The SRAM CODE four piston brakes feature tool-free bite point and lever reach adjustments as well as SRAM’s proprietary SwingLink technology, which is designed to minimise deadband and optimise modulation.
The brakes are paired with big 200 mm rotors front and rear, ensuring a powerful braking performance even on long, steep descents.

For the dropper, YT Industries rely on their in-house components, using a 170 mm Postman V2 dropper on frame size L. This can be inserted all the way into the frame, but it’s far too short for a modern trail bike. Renthal supply the cockpit, combining an Apex 35 stem and 780 mm FatBar 35 alloy handlebars. Our test bike rolls on a Crankbrothers Synthesis alloy wheelset with a classic MAXXIS combo, with a Minion DHF up front and Minion DHR II at the rear, both in the puncture-prone EXO+ casing and hard MaxxTerra rubber compound. Both heavy and rowdy riders should upgrade to the more robust Doubledown casing for better puncture protection and softer MaxxGrip compound for better traction at the front.

YT’s in-house Postman V2 dropper post only has 170 mm of travel, which is far too short for a modern trail bike in size L.
Both tires come in the thin EXO+ casing and hard MaxxTerra rubber compound. Heavy and rowdy riders alike should upgrade to a more robust casing and softer MaxxGrip rubber compound at the front.


€ 5,999


Fork FOX 36 Factory GRIP2 150 mm
Rear Shock FOX FLOAT X Factory 145 mm
Seatpost YT Postman V2 170 mm
Brakes SRAM CODE RSC 200/200 mm
Drivetrain SRAM X0 Eagle Transmission 1x12
Stem Renthal Apex 35 mm
Handlebar Renthal FatBar 35 780 mm
Wheelset Crankbrothers Synthesis Enduro Alloy 29"
Tires MAXXIS Minion DHF MaxxTerra EXO+/Minion DHR II MaxxTerra EXO+ 2,5"/2,4"

Technical Data


Specific Features

Storage compartment
Flip Chip
Tool Mount

All spec variants of the 2024 YT JEFFSY

As already mentioned, the new 2024 YT JEFFSY is available in both aluminium and carbon versions, and in many different colours. Alongside the CORE 5 CF spec variant we tested, there are four more affordable models to choose from, whereby YT don’t offer a top-spec variant of the alloy version. Both alloy models as well as the CORE 3 CF carbon entry-level model rely on a cable-operated drivetrain and more basic forks, which employ a lower-tier yet easily adjustable damper. The CORE 4 CF variant just below the flagship model comes equipped with a new, electronic SRAM GX Transmission drivetrain and top-tier RockShox suspension consisting of a Lyrik Ultimate fork and matching Super Deluxe Ultimate air shock. The fork’s easily tuneable, high-quality Charger 2 damper offers countless adjustment options and delivers a tremendous performance on the trail, sitting at the same level as FOX’s Factory suspension. Excluding the € 5,999 flagship model, prices for the new 2024 JEFFSY range between € 2,499 and € 4,999 and we wouldn’t be surprised if YT released a special Uncaged edition in the near future.

The geometry of the new 2024 YT JEFFSY

The YT JEFFSY 2024 is available in 5 sizes, S to XXL. However, with a rather conservative 475 mm reach in size L, YT’s sizing is on the small side. At 435 mm, seat tube length is average, and the geometry can be changed via a flip chip in the shock mount. Needless to say, we rode the bike primarily in the low setting, which is also the one we liked best. In the high setting, both the head and seat tube angle steepen up by 0.6°, while the bottom bracket lifts by 8 mm. Chainstay length is 437 mm in frame sizes S to L, and grows by 5 mm in frame sizes XL and XXL, which is meant to ensure consistent handling across all sizes.

Top tube 578mm 593 mm 609 mm 627 mm 645 mm
Seat tube 385 mm 410 mm 435 mm 460 mm 485 mm
Head tube 100 mm 108 mm 116 mm 124 mm 132 mm
Head angle 65° 65° 65° 65° 65°
Seat angle 77.2° 77.2° 77.2° 77.2° 77.2°
Chainstay 437 mm 437 mm 437 mm 442 mm 442 mm
BB Drop 33 mm 33 mm 33 mm 33 mm 33 mm
Wheelbase 1,191 mm 1,214 mm 1,238 mm 1,266 mm 1,289 mm
Reach 435 mm 455 mm 475 mm 495 mm 515 mm
Stack 613 mm 620 mm 627 mm 634 mm 642 mm
Helmet Smith Session MIPS | Glasses Coast Optics Nita | Jacket Velocio Recon Vest |
Jersey Velocio Delta Trail Longsleeve | Pants Velocio Trail Access Pant | Shoes Crankbrothers Mallet Speedlace

The new 2024 YT JEFFSY CORE 5 CF on the trail

As soon as you swing your leg over the saddle, the 2024 YT JEFFSY CORE 5 CF places you in a compact pedalling position without putting too much pressure on your hands, thus allowing you to cover even longer distances without getting too tired. When you start climbing, the rear suspension generates good traction and only bobs slightly, making it easy to reach the trailhead even without activating the climb switch. As a result, the JEFFSY is an excellent companion for epic days in the saddle with plenty of elevation gain. When negotiating steeper climbs, the front end stays on track without the need to weight the front wheel.

When you drop into a trail to shred your way back down into the valley, the YT JEFFSY integrates you nicely between its wheels, making you feel at ease from the get-go. Handling is pleasantly intuitive, making the JEFFSY easy to ride for beginners while at the same time allowing seasoned trail veterans to safely make their way back to the car park on a technical trail, even after a long day in the saddle. The high front end inspires huge amounts of confidence and prevents unpleasant OTB moments on steep trail sections, though without forcing you to actively weight the front wheel in open corners. Overall, the 2024 JEFFSY feels at home on flowing, curvy trails, where the agile handling and poppy suspension allow you to flick the bike from one berm into the next, and generate speed by pumping through rollers with a massive grin on your face! At the same time, the sensitive suspension offers enough reserves to bail you out of botched landings. The JEFFSY doesn’t shy away from rowdy enduro trails either, taking on even nasty rock gardens with a big pair of cahoonas. That said, rough, technical trails require an active, vigilant riding style and good skills.

Who should take a closer look at the 2024 YT JEFFSY?

First and foremost, the YT JEFFSY CORE 5 CF delivers a ridiculous amount of fun, especially on flowing trails with rollers and berms, where the lively yet intuitive handling encourages you to carve through corners at MACH10, whether you’re a beginner or seasoned trail warrior. However, the JEFFSY doesn’t shy away from technical singletracks either, proving to be the excellent all-rounder that it claims to be, while the central, comfortable pedalling position also makes it an excellent companion for epic backcountry adventures. If you’re looking for a versatile, fun trail bike with a top spec and excellent price-performance ratio, the JEFFSY might be exactly what you’re looking for.

Our conclusions about the 2024 YT JEFFSY CORE 5 CF

While YT didn’t reinvent the wheel with the new 2024 YT JEFFSY, they deliver a sensible reiteration of a true classic, with modern details like the storage compartment and tool strap on the top tube. The latest descendant of the JEFFSY dynasty convinces with an excellent price:performance ratio and top spec – except for the short-travel dropper post. The intuitive handling makes it a great option for both beginners and experienced riders, who will particularly enjoy its tremendous fun factor. Overall, the 2024 YT JEFFSY CORE 5 CF is an outstanding all-rounder that manages to successfully combine touring capabilities and trail performance.


  • Intuitive handling suits both beginners and advanced riders
  • Functional frame details
  • Top spec at a very fair price


  • No top-spec alloy variant
  • Cables aren’t clamped properly

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Words: Mike Hunger Photos: Peter Walker Translation: Eric

About the author

Mike Hunger

From slopestyle and landscape photography to enduro and action shots. Mike enjoys trying new things and loves action. He also loves craftsmanship, regularly going on road trips with his VW Syncro van, which he restored and converted himself. Of course, his bike and his camera are always with him so that he can ride the finest trails from Italy to the Alps and capture the most beautiful moments. Thanks to his training as an industrial mechanic, his experience in cycling and his photographic skills, he can apply his know-how perfectly as a bike journalist, testing the latest bikes and components and documenting his findings. As a photography nerd, he also captures the reviews with his camera and ensures that the magazine features only the best images.