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The Beta Tests

The Beta Tests: YT Jeffsy Core 2 29

A great value with an appetite for rowdier trails. . 


-150mm front and rear travel
-29-inch wheels
-27.5-inch version also available in all sizes
-Aluminum frame


-Incredibly capable
-Incredibly fun
-Incredibly versatile
-Incredible value


-Pedal bob had us using the lockout on long climbs
-Slightly limited water bottle space
-Could use stronger brakes







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The YT Jeffsy is not a new bike. It’s been reviewed to death since it was updated almost three years ago. But it took a while for the aluminum Jeffsy to catch up.  You can still pay up to $9500 for the tricked-out “Uncaged” version of the Jeffsy, but we tested the more-approachable $3k Core 2 model, which has a sturdy aluminum frame and a capable but price-conscious spec. 

All that to say: value was always going to be the main story with this bike—but the Jeffsy turned our usual value conversation on its head. Many “affordable” bikes lose their defining qualities in an attempt to be every bike for a rider. They do a lot of things moderately well, with the assumption that riders on a budget want to dabble in different types of riding on the same bike. The inevitable consequence is that these bikes don’t usually do any one thing really well. This is not the case with the Jeffsy.

As hyper-critical testers, we tend to accumulate a rolling list of complaints as we go along, but on the Jeffsy, most of our gripes at the top were resolved by the bottom. The low bottom bracket, which resulted in bashed pedals for every tester on the climbs, became a stabilizing asset on descents. The active kinematics, which caused heavy utilization of the suspension lockouts on the way up, gave the bike more traction on the way down. In short, this is a bike with a distinctly gravity-hungry nature—a bike with defining qualities. 

While it may not be able to go toe-to-toe with its pricier competitors when it comes to nuanced handling, the Jeffsy held its own through the big drops, root balls and bermed corners on our test loop. We worried that its somewhat vague-feeling climbing characteristics would translate into a sedate, heavy quality on the way down—but it holds the line right at reassuring. In fact, the Jeffsy seems surprisingly eager for whatever you want to throw at it, and that makes for fast, confident riding. 

So, back to the value conversation. What is the value of a $3k mountain bike that is biased towards descending? As always the answer will depend on where the rider lives, what kind of riding they like to get into, and what their budget is. Is this bike a great value if you want to ride rolling, moderately technical trails? Probably not. But if you have access to rowdy, steep trails (and probably a shuttle now and then) you’ll be hard-pressed to find a better bike at this price. 

YT is a direct-to-consumer brand. Since you get the bike in the mail, you’ll be the one who sets it up, which has the benefit of requiring that most parts be easy to assemble and service. The exception on this bike is the press-fit bottom bracket, which is not only annoying to service, but an odd choice in an aluminum frame, which could more easily have threads instead of extra cups. We were also a little disappointed in the brand’s proprietary Postman dropper, which seemed to bind when not engaged at just the right angle. 

Other cost savings come from the drivetrain (SRAM NX Eagle) and slightly underpowered SRAM G2 brakes, but these should serve most riders well in most situations. And the rest of the bike is solid enough that they’re worth swapping out if you decide to upgrade in the future. And speaking of upgrade, we just learned that YT will be making a running change to the new Fox Float X rear shock from the DPX2 on our test bike. 

For a bike that will open up bigger terrain, the YT Jeffsy Core 2 is an affordable option that brings a little extra attitude on descents. 

Studio photos: Ryan Palmer

Action photos: Paris Gore