Words by Brett Watts // Photos by Ryan Wiegman
As a content creator for usabikers.net, I’m excited to delve into the world of Yt Mountain Bikes, specifically the Jeffsy model. When The Loam Wolf rolled into town with a fleet of bikes for testing, I was eager to participate. At the time, my personal ride was a blacked-out 2015 Santa Cruz Nomad, enhanced with wide Enve carbon wheels. Let’s be honest, the black finish adds to the speed, right? I was thoroughly satisfied with the Nomad, pushing it hard on aggressive trails, and it consistently performed. My approach to frame and suspension design is generally “keep it simple.” Intricate designs and hyped-up innovations rarely impress me. My background in aviation maintenance, dealing with advanced materials similar to those used in modern bikes, likely contributes to my preference for proven technology over marketing buzzwords.
However, certain bike characteristics do pique my interest. The YT Jeffsy, even before seeing it in person, ticked all the right boxes. Its design is straightforward, avoiding unnecessary complexity. It utilizes a refined four-bar suspension system, a design proven effective for years. True to German engineering, YT has incorporated its unique touches to make it their own. Let’s revisit my checklist of desirable features:
- Carbon frame (both front and rear triangle)
- Carbon wheels
- Carbon cranks
- Carbon handlebars
- A simple, reliable suspension system maintaining direction throughout its travel
- A sloping top tube providing ample maneuverability, crucial for jumps
- An uninterrupted seat tube for maximum seatpost drop, essential for aggressive riding
- A slack headtube angle for confident descending
- Black color scheme (arguably the most crucial element)
YT Jeffsy Review
When The Loam Wolf arrived with their bike collection, it resembled a buffet of mountain bikes. I scanned the piles, hoping to find a YT Jeffsy. I had been curious about YT’s trail bikes for months and hadn’t yet seen one firsthand. Finally, I spotted it: a YT Jeffsy CF Race Pro. This model was impeccably equipped, a build I couldn’t have improved upon myself – and importantly, it was BLACK!
My initial impression, after a quick neighborhood spin, was simply “this thing is fast!” This was also my first experience on a 29er, and I confess to being a former critic of the wheel size. Yes, I was one of those guys. This bike effectively silenced my 29er skepticism. It felt remarkably similar to my aggressive Nomad while riding on pavement, with comparable balance points. It was naturally inclined to wheelies and manuals, making playful riding effortless. I was eager to test it on the trails.
Once on familiar trails, the Jeffsy continued to impress. I felt an advantage over the other testers, riding on my home turf, trails I knew intimately and had ridden on bikes with all three wheel sizes. The rolling efficiency of the 29-inch wheels was immediately noticeable. I had hoped to find a flaw to justify my previous 29er criticisms, but I was out of luck. The YT Jeffsy’s 29-inch wheels absorbed trail obstacles and, surprisingly, rolled faster through familiar sections. The bike was remarkably quiet, and the geometry perfectly suited my riding style.
The suspension performance was progressive, and even on larger jumps, harsh bottom-outs were never an issue. The YT Jeffsy handled smaller trail chatter and roots well, but as the bumps became larger and faster, some lighter riders felt the suspension was geared more towards playfulness and jumps, potentially sacrificing some composure on very rough, high-speed terrain. Weighing more than most of the other riders by at least 15lbs, I didn’t struggle to access full travel. However, when encountering more extensive root networks and rock gardens, I did notice the suspension transitioning from capable to feeling somewhat overwhelmed. The group largely attributed this to the bike’s shorter travel. Admittedly, these were trails where I typically ride bikes with 160mm or more travel, but the Jeffsy’s excellent geometry and overall feel made this seem less of a limitation initially. Any bike can reach its limits, but I was amazed at how aggressively I could push this bike on terrain usually reserved for downhill bikes.
Jumping is integral to my riding, and my local trails are full of significant jumps. Still clinging to the hope of finding fault with 29ers, I ventured onto one of the jump-filled flow trails, thinking the jumping performance surely wouldn’t match its all-around capabilities. Again, I was wrong – the Jeffsy flies exceptionally well! It felt stable off jumps and was easy to control in the air. After hitting all the jumps on my favorite trail, including a tall overhead double and a substantial step-down, I started to realize, “I could genuinely ride this YT mountain bike every day. It’s capable enough to handle anything I’m willing to ride!”
