The current Jeffsy frame platform is already four years old. Since then, the all-mountain bike from Forchheim has only received model updates in the form of new colour and equipment variants. The Core 4 version we tested is the top-of-the-range model. For 4999 euros, the Jeffsy has Fox Factory suspension with 150 millimetres of travel, a Sram X01 Eagle drivetrain and aluminium wheels from DT Swiss. This means that the robust all-mountain bike weighs in at 14.4 kilos without pedals - the second best value in the comparison.
YT Jeffsy Core 4: Uncompromising all-mountain bike downhill
A closer look at the spec makes it clear: YT makes no compromises when it comes to downhill performance. Just like with Specialised Stumpjumper, Radon Slide and Focus Jam 200 mm brake discs are used at the front and rear. A solid chain guide is also on board. On the front wheel, the Maxxis Minion DHR in the soft MaxxGrip rubber compound generates enormous traction. While a Fox Float-X shock is used at the rear, a Fox 36 suspension fork with a multi-adjustable Grip2 cartridge smoothes out the bumps on the front wheel. The rear is forgiving, but offers comparatively good support when pushing through berms or pushing off jumps.
The riding position is immediately pleasing. Thanks to the moderate reach and steep head angle, the YT Jessy Core 4 can be ridden intuitively and without long familiarisation. Paired with the shortest wheelbase, the MTB turns out to be the most lively candidate on winding trails. However, the longer and flatter geometries of the competition provide more confidence on rough, full-throttle sections. Thanks to the compact riding position, you can also survive long days in the saddle. The rear suspension only bobs slightly in open mode.
Test summary by Max Fuchs, BIKE editor:
Even if the geometry of the YT Jeffsy Core 4 has gathered some dust, the great handling and the well-designed suspension make it a lot of fun to ride. On tour, the low weight plays into your hands.
Technical data and notes on the YT Jeffsy Core 4
Manufacturer information
- Price: 4999 Euro²
- Available by mail order
- Frame material: Carbon
- Frame size: S, M,L, XL, XXL(tested size L, 44 cm)
Measured values
- Weight without pedals: 14.36 kg
- Frame weight without shock: 2757 g
- Weight of wheels: 5190 g
- Handlebar width: 790 mm
Equipment
- Fork: Fox 36 Float Factory Fit Grip2
- Shock: Fox Float X Factory
- Front/rear suspension travel: 150/154 mm
- Crank: Truvativ Descendant Carbon
- Gear system: Sram X01 Eagle 1 x 12
- Gear ratio / bandwidth: 32; 10-52 / 520 %
- Brake system / Disc (front / rear): Sram G2 RSC / 200 mm / 200 mm
- Telescopic post / stroke / Ø: YT Postman / 170 mm / 31.6 mm
- Wheels: Crankbrothers Synthesis E 29
- Tyres: Maxxis Minion DHR II; 3C MaxxGrip / MaxxTerra Exo Protection TR 29 x 2.40
- Ease of maintenance: weak
BIKE test rating¹: very good - 189.5 out of 250 points
The BIKE judgement reflects the laboratory measurements (BIKE laboratory measurement) and the subjective impression of the test riders. The BIKE judgement is independent of price. BIKE judgements: super (250-205 P.), very good (204.75-180 P.), good (179.75-155 P.), satisfactory (154.75-130 P.), with weaknesses (129.75-105 P.), unsatisfactory (104.75-0 P.).
²Price may be subject to additional costs for packaging, dispatch and coordination.
Max Fuchs
Editor
