YT Jeffsy Review


Not Your Dad’s 29er

Words by Brett Watts // Photos by Ryan Wiegman

When I heard The Loam Wolf was coming to town with a stack of prototype and production bikes for a no-holds-barred shakedown test, I was beyond pumped. At the time of the trip, I was riding a murdered-out 2015 Santa Cruz Nomad with a set of wide Enve carbon hoops. The murdered-out part is vital because, as we all know, black bikes are measurably faster. I was extremely pleased with the Nomad and put it through the wringer, thanks to my aggressive riding schedule. It always took the beatings and came back for more. I am a “Keep it Simple” minded rider when it comes to frame and suspension design. I don’t get easily wooed by intricate designs or the latest and greatest. Breakthrough bullshit hardly raises an eyebrow for me. My professional background is in aviation maintenance, and I routinely use the same materials and lingo that modern-day, space-aged bikes are now using, which is probably where my stubbornness to try something new comes into play.

When it comes to bikes that do attract my attention, they must meet certain criteria. The YT Jeffsy put a checkmark in each box far before I ever saw the bike in person. It’s simple – no crazy reinvention of the wheel. For the most part, it features an adopted/improved four-bar suspension design that’s been tried and true for years. Like everything the Germans touch, YT put their own slick engineering twist on things to make it their own. We should get back to that checklist. Here’s what revs my motor:
• Carbon frame (front and rear triangle).
• Carbon wheels.
• Carbon cranks.
• Carbon bars.
• A simple, clean looking suspension that doesn’t switch direction through the stroke.
• Swept down top tube with plenty of room to move around since I’m a jumper.
• Uninterrupted seat tube so I can get the seat slammed and out of the way.
• Slack headtube.
• Black (the most important).

YT Jeffsy Review

When The Loam Wolf showed up, I saw piles of bikes stacked like plates at the Hometown Buffet. I looked through all of them, searching each pile with the hopes that I’d find a YT Jeffsy. I had been curious for months as to how YT’s trail bikes would ride and had yet to see one in person. Eureka, I found it. A YT Jeffsy CF Race Pro. Now, this thing was dialed to the nines. I couldn’t have put a better build on it if I tried – plus… BLACK!

My first impression after throwing pedals on it and riding around the neighborhood was, “this thing’s fast!” This was also the first 29er I had ever ridden, and I come from a long tradition of wheel size bashing. Yeah, I was that guy. This bike cleaned those 29er jokes out of my mouth like a Catholic nun. It felt just like my angry Nomad while beating up the streets, and the balance points were nearly the same. It loved the back wheel. Wheelies were automatic, and manualing was a breeze. I couldn’t wait to get it in the dirt!

Once on the trail, it continued to impress. I felt like I had a real leg up on the rest of the bike testers – I was in my zone, riding dirt that I knew, and riding trails that I had ridden on all three wheel sizes. The first thing that grabbed my attention was how the wagon wheels rolled. I wanted this to be a weakness so I could continue with my normal wheel size bashing, but no such luck. The YT Jeffsy 29-inch wheels ate up everything in their path and, surprise surprise rolled noticeably faster through known sections of trail. The bike itself was extremely quiet, and the geometry fit my riding style beautifully.

YT Jeffsy Review

The suspension stroke was definitely progressive, and even on the biggest jumps, I never felt like it bottomed harshly. The YT Jeffsy worked pretty well on little rubble and roots, but when the bumps got bigger and faster, some of the lighter riders in attendance felt the suspension was a bit too “parky or jumpy,” voicing that the bike sacrificed a bit of composure on rough, rowdy terrain to achieve a more playful feel. With at least an extra 15lbs on most of the other riders, I didn’t have trouble getting full travel, but as I worked up to more extensive roots and rock gardens, I felt the suspension quickly go from keeping up to feeling outgunned. The group all attributed this in significant part to the shorter amount of travel. Granted, these were trails where I usually rode a 160mm or greater travel bike, but the geometry and feel are so good it didn’t seem like it would be an issue. Any bike can get in over its head, but I was blown away with how hard I could smash this thing into terrain that I usually rode a DH bike on.

Jumping is a huge part of my riding experience, and most of the trails I enjoy are littered with big hits. Still hanging on to that hope of cracking 29er jokes, I dropped into one of the flowiest and jumpy trails around and thought, surely, this thing won’t jump as well as it does everything else. Wrong again – the damn thing flies! Super stable off the lip and easy to maneuver in the air. After hitting all the jumps on my favorite local trail, which includes an overhead tall, 30-foot double, and a 10 by 20-foot stepdown, I began to think, “I could really ride this bike every day. It is capable of handling anything I can throw at it!”

This bike cleaned those 29er jokes out of my mouth like a Catholic Nun.

The Wolf’s Last Word

This review may make it sound like I really enjoy this bike. You’d be right. I liked it so much I had to have it. The Pack put me in direct contact with their connection at YT, and I gave them my credit card right over the phone, and when the Wolf Pack left Humboldt, they had one less bike to take home. I have been riding it as my daily bike for several months, and my feelings towards it have not changed. I am still blown away with how well it handles everything – turns, roots, jumps – the YT Jeffsy can handle it all. After months of at least four hard rides a week, I haven’t had to repair anything beyond some shock bushings and spoke tension on the DT Swiss carbon wheelset. Both are things I would consider to be routine after the beating she’s been given. If you’re a rider looking for a trail bike that rides more like a park or jump rig than an XC machine, look no further. Snappy handling dialed geometry, and a super playful suspension curve make the YT Jeffsy a blast to ride on new school trails.

Price: $5,599

Weight: 28.13 lbs

Sizes: S, M, L (Tested), XL



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Frame: Carbon; 140mm
Fork: Fox Factory 34; 140mm
Shock: Fox Factory Float X

Brakes: SRAM Guide Ultimate
Handlebar: Renthal Fatbar
Headset: Across AIX
Saddle: SDG Fly Mountain
Seatpost: Rock Shox Reverb; 150mm
Shifter: SRAM X01
Stem: Renthal Apex; 50mm

Hubs: DT Swiss
Rims: DT Swiss
Tires: Onza Ibex; 29 x 2.4

Bottom Bracket: Race Face BB92
Cassette: E.Thirteen TRS+
Cranks: Race Face NEXT SL
Derailleur: SRAM X01

Geometry (Large)

YT Jeffsy Geo Diagram

A Toptube length: 616 mm, B Reach: 445 mm, C Stack : 623 mm, D Seattube length: 480 mm, E Chainstay length: 440 mm, F Headtube angle low/high: 67 / 67.5 degrees, G Seattube angle (eff.) low/high: 74.5 / 75 degrees, H BB Drop low/high: 32/24 mm, I Wheelbase: 1,178 mm, J Headtube length: 110 mm, K Steerer tube length: 551 mm, L Fork offset: 46 mm.

We Dig

Beyond Playful
Snappy, Quick Handling
Loves Air & Backwheel

We Don’t

Rear Suspension on High Speed, High Frequency Hits