At a glance
In a sea of big wheeled All Mountain bikes, there is little on offer for the 27,5 enthousiast. The 160mm travel Jeffsy Core 2 is a bike that stands out from the crowd. At 2999 Euro / 2649 GBP / 2999 USD the Fox / Sram equipped machine is delivered with an aluminium frame.
The Jeffsy is also offered with 29’’ wheel option, carbon frame and various other build options.
About the brand
YT Industries is a German brand founded by Markus Flossman back in 2007. Fuelled by the goal to make high quality bikes affordable and accessible to everyone, the brand has been working hard over the years to deliver that promise. With ‘Good Time’s as their slogan and a downhill oriented mindset when designing their products, they have quickly become a big name in the world of off-road brands.
Their direct sales strategy through the website enables them to consequently win the ‘value for money’ game. Sometimes criticized for lack of customer service, YT went on a path to up their ante with the opening of ‘YT Mill’ stores in key places and doubling up on their customer service staff.
On the subject of sustainability and the environment, YT takes responsibility for getting their E-Bike batteries recycled. Once past their life cycle, you can send them back to their HQ. Sadly there are no mentions of efforts on reducing their carbon footprint, climate neutral production or supporting NGOs or trail advocacy groups.
As mentioned, the YT Jeffsy comes in both 29’’ and 27,5’’ offerings. The big wheeled bike has 150mm travel, while the tested 27.5’’ model comes with 160mm front and rear. YT’s alloy frame features their proven Virtual Four link suspension system and a flip chip that enables you to switch between a higher bb / steeper head angle or a lower bb / slacker head angle setup. To keep you hydrated and not compromise their suspension design, YT made a special Fidlock bottle that fits neatly in their frame.
One thing you immediately notice is the attention to detail with the frame. There are high quality protection rubbers on all critical points making sure your bike is silent and protected from chain slap, rocks and small furry animals. The internal cable routing gives the bike a clean look. The bike comes in 5 different frame sizes, making it easy to choose an optimal size for you. The frame is rocking a modern geometry with a 462mm reach on the tested size L. A 65.5 degree head angle is pretty average for an all mountain bike, with a 432mm chainstay that makes the bike agile and playful.
When it comes to spec, the YT definitely does not disappoint. With a DT Swiss M1900 wheelset, it should hold up some serious riding. Maxxis Minion DHRII tires (Exo Casing) make sure you have grip when you need it.
Suspension duties are handled by Fox with a Float DPX2 performance rear shock, and a Fox 36 Float Performance front forks. Although they are not Kashima Coated, they offer a lot of adjustment options to fine tune your ride. To be honest, the lack of gold won’t affect the ‘smiles per hour’ factor much, and let’s keep in mind that this is a 2799 Euro bike.
Cockpit is supplied by E13, which is a solid alloy handlebar/stem combo. The ODI grips are very comfy, and YT’s own Postman dropper post functions smoothly. Good to know is that it comes with 125mm drop on frame sizes S and M, 150mm drop on the L and 170mm on the XL and XXL sizes.
Drivetrain duties are handled by the mighty SRAM with their 12 speed NX Eagle groupset and a descendant crankset with a 32T chainring in the front. To slow yourself down you have to rely on Sram G2 R brakes, equipped with 200mm rotors front and rear.
Out on the trail
After setting up the sag and saddle height, we headed to our local test loop to get a feel for the Jeffsy. Climbing out of the car park, we immediately notice that this is not the favorite bit of mountain biking for the YT. After adjusting the saddle in the most forward position possible it gets a bit more comfortable, and you don’t need to worry about getting to the top either. It’s just not a bike you hop on and smash all your KOM’s on the climbs.
When we pointed the YT down the trails there was no other option for the corners of our lips to move upward. The reach on the frame is nice and spacious, giving you the opportunity to ride really actively. As 27,5’’ wheeled bikes go, this Jeffsy wants to play. Jump from that tree root, pop a manual in between corners and nose wheelie through those tight turns.
When things get steep, the geometry holds its own. If you ride steeps a lot, make sure to switch to the lower slacker flip chip setting. If you’re more on man made, flowy trails you’ll find the higher setting more balanced.
It’s easy to forget when you ride big wheeled bikes a lot, just how easy the smaller wheeled cousin goes through tight switchbacks.
When the going gets rough, the YT’s suspension really shines. Both shocks are well balanced, and the rear has a lovely progressive curve, making the travel feel endless. Because of their Virtual Four link suspensions’ design, flexing forces from the rear triangle are not transferred to the shock, which means longer bearing life, and smoother suspension action.
The only thing that was holding us back was the brakes. The 200mm rotors really helped a lot to make the most of the Sram G2R brakes, but they were just lacking in bite and power. Especially for the speeds the Jeffsy takes you. Perhaps if you replace the stock pads with some aftermarket ones you can boost the power a bit or over time get an upgrade.
What a fun and capable bike. The value for money is unbeatable, and there is no compromise in frame quality either. There is a great amount of detail on the frame from frame protection to nice oversized bolts and bearings. Out on the trail the bike is playful with an appetite for steeper, rougher terrain. If you have a 3k budget for a new bike, get the order placed and sign up for the next Enduro Uplift day!Buy Enduro Bikes on
This review was in Issue 65 of IMB.For more information visit YT Industries
By Jarno HooglandJarno's life has revolved around two wheels ever since he swung a leg over his first BMX at age 4. After a BMX and DH racing career, he moved on to work for bike shops, distributors and brands before ending up in the editors seat at IMB. Based in the ultimate testing ground in the Swiss mountains, he runs his guiding operation and makes sure every IMB issue is filled with top notch content.