The YT Jeffsy Core 3 won the test in our test of all-mountain bikes around 4000 euros. Now the successor is already in the starting blocks. The basic concept and frame remain unchanged, but YT has fundamentally revised the equipment. Also new: in addition to the carbon options, aluminium frames are now available again up to the upper mid-range.
YT Jeffsy 2025: The most important facts at a glance
- Suspension travel: 150/145 millimetres
- Frame material: carbon or aluminium
- Wheel size: 29 inch
- Available sizes: S, M, L, XL, XXL
- Chainstays: 437 mm (S-L), 442 mm (XL-XXL)
- Steering angle: 65 degrees
- Seat angle (effective): 77 degrees
- Prices: from 2799 Euro
Tried and tested: Frame and features of the YT Jeffsy
You already know the carbon frame with storage compartment from the 2024 Jeffsy, which we presented extensively back then. YT Industries calls the storage compartment a "stash" and equips it with a double-sealed flap. This is intended to ensure watertightness and reduce noise. The aluminium version of the Jeffsy has to make do without this storage compartment, but offers attachment points for tools on the top tube. The price difference between the carbon and aluminium frame is 500 euros, with the carbon chassis the bike is 600 to 700 grams lighter.
Both frame variants use the same progressive V4L kinematics for the rear triangle. The chainstays are size-specific: for frame sizes S to L, the length is 437 millimetres, for XL and XXL it is 442 millimetres. This is intended to achieve a balanced riding behaviour across all sizes. The steering angle of 65 degrees is modern, but not extreme, and the seat angle is still a pleasantly steep 77 degrees.
Four equipment variants, carbon fibre from 3999 euros
YT Industries offers the Jeffsy in four equipment variants. The top-of-the-range Core 4 model has a carbon frame made from ultra-modulus fibres. The suspension elements come from Fox: a 36 mm fork with GRIP2 cartridge at the front and a Float X shock at the rear. The wheels are from DT Swiss, model EXC1501 Spline. They have carbon rims and 240 hubs and are even approved for enduro use. As before, the tyres consist of Maxxis Minion DHF at the front and the DHR II at the rear, with the front tyre now being fitted with the sticky Maxxgrip compound. This tyre combination can be found in all Jeffsy variants. The top model brakes with Hayes Dominion A4, while a Sram X0 Transmission drivetrain provides propulsion. The equipment is completed by the YT Postman V2 dropper post, an SDG Bel Air saddle, ODI grips and a YT-exclusive Renthal Apex stem and Fatbar handlebar.
YT Jeffsy Core 4
- Frame: Carbon
- Fork: Fox 36, 150 mm travel
- Shock: Fox Float X, 145 mm travel
- Gear system: Sram X0 Transmission
- Brakes: Hayes Dominion A4
- Wheels: DT Swiss EXC1501 Spline
- Variable seatpost: YT Postman V2
- Weight: 14.6 kg (manufacturer's specification)
- Price: 5999 Euro
Further model variants
The YT Jeffsy Core 3 is available with both an aluminium and carbon frame. The suspension elements come from Rockshox: a Lyrik Ultimate fork with Charger 3.1 cartridge works at the front, a Super Deluxe shock with HSC/LSC setting at the rear. The gears are changed by a transmission in the favourable S1000 version. The bike rolls on Crakbrothers Synthesis Enduro 2 wheels and the cockpit corresponds to that of the top model.
YT Jeffsy Core 3
- Frame: Carbon / Aluminium
- Fork: Rockshox Lyrik Ultimate, 150 mm travel
- Shock: Rockshox Super Deluxe, 145 mm travel
- Gear system: Sram T-Type Transmission S1000
- Brakes: Hayes Dominion
- Wheels: Crankbrothers Synthesis Enduro 2
- Weight: 15.8 / 15.1 kg (manufacturer's specification)
- Price: 4499 Euro / 4999 Euro
The Jeffsy Core 2 also offers a choice between aluminium and carbon. Fox Performance suspension elements are used here. The drivetrain combines a Shimano XT gear lever with an SLX drivetrain. Braking is also provided by Hayes Dominion with 200 millimetre discs, while the wheels come from DT Swiss (E1900). The handlebars and stem are YT and Raceface components respectively.
The entry-level Core 1 model is only available with an aluminium frame in Drip Yellow. It uses a Marzocchi Bomber chassis, a Shimano Deore drivetrain and SRAM DB8 brakes with mineral oil. The wheels are from Sun Ringlé and the cockpit consists of YT components.
YT Jeffsy Core 2
- Frame: Carbon / Aluminium
- Fork: Fox Performance, 150 mm travel
- Shock: Fox Performance, 145 mm travel
- Shifting: Shimano XT shift lever, SLX rear derailleur
- Brakes: Hayes Dominion
- Wheels: DT Swiss E1900
- Weight: 15.7 / 15.1 kg (manufacturer's specification)
- Price: 3499 / 3999 Euro
YT Jeffsy Core 1
- Frame: Aluminium
- Fork: Marzocchi Bomber, 150 mm travel
- Shock: Marzocchi Bomber, 145 mm travel
- Gear system: Shimano Deore
- Brakes: Sram DB8
- Wheels: SUNRinglé
- Weight: 16.5 kg (manufacturer's specification)
- Price: 2799 Euro
Adrian Kaether
Editor
