

There was no shortage of hype surrounding the YT Jeffsy, partially due to the extensive (and slightly odd) ad campaign that YT ran in the months prior to its release. When the cloak of secrecy was lifted to reveal a 140mm 29er, there were certainly some surprised riders out there.



After all, this is the same company whose focus has been on maintaining a 'No f*cks given' image, with wild men like Andreu Lacondeguy and Cam Zink representing the brand – a 29er trail bike isn't exactly what comes to mind when you think of those two riders. The thing is, most riders don't have Red Bull Rampage-sized hucks in their backyards, which is why it made a lot of sense for YT to add a more well-rounded bike to their arsenal.







YT Jeffsy CF Comp 1 Details



• Intended use: trail / all-mountain

• Rear wheel travel: 140mm

• Wheel size: 29"

• Carbon fiber frame

• BB92 bottom bracket

• 12x148mm rear spacing / 15x100mm front

• Sizes: S, M, L, XL

• Weight: 28.8lb lb / 13.06 kg (size large)

• MSRP: $4,599 USD

• www.yt-industries.com / @YTIndustries • Intended use: trail / all-mountain• Rear wheel travel: 140mm• Wheel size: 29"• Carbon fiber frame• BB92 bottom bracket• 12x148mm rear spacing / 15x100mm front• Sizes: S, M, L, XL• Weight: 28.8lb lb / 13.06 kg (size large)• MSRP: $4,599 USD

The rear derailleur cable is routed through the carbon frame, with all of the other housing running along the top of the down tube. A flip chip on the seatstays allows for two different geometry settings (the low position is shown).

Frame Details

A full-size water bottle won't fit, but YT do offer the Thirstmaster 3000, a small, squat bottle and cage designed specifically for the Jeffsy. It's nice to see a 150mm dropper post in place on the M, L, and XL sizes.

Suspension Design

Geometry

Specifications

Specifications Price $4599 Travel 140mm Rear Shock Monarch RT3 Fork RockShox Pike RCT3 46mm offset, 15x100mm Headset Acros AiX-326 Cassette SRAM XG 1150 Crankarms Race Face Turbine Bottom Bracket Race Face Rear Derailleur SRAM X1 Chain SRAM PC1130 Shifter Pods SRAM X1 11-speed Handlebar Race Face Stem Race Face Turbine (50mm S/M, 60mm L/XL) Grips Sensus Brakes SRAM Guide RSC Wheelset DT Swiss M1700 Spline Tires Onza Ibex 2.4" Seat SDG Circuit Seatpost RockShox Reverb 150mm Compare to other All Mountain/Enduro/XC



Climbing

Donny Allison dropping in aboard the Jeffsy.

Descending

That playful and peppy nature is due in part to the the Jeffsy's progressive suspension curve, which makes it incredibly well-suited to trails filled with bermed turns, rollers, and jumps.

The 140mm RockShox Pike worked flawlessly... ...although issues cropped up with the Reverb post and Guide RSC brakes.

Component Check

The DT Swiss M1700 Spline wheels made it through the test period unscathed, but this bike is a prime candidate for wider rims. Onza's Ibex tires aren't the grippiest option for wet weather riding.

Pinkbike's Take:



The Jeffsy leaves little to be desired out on the trail, and no matter whether your ride takes you on a mild XC loop or a more wild, technical trail, a lively, energetic performance is in store. There were a few component related issues, and riders in wetter climates should be prepared to swap out the tires, but on the whole, the Jeffsy's price vs. performance ratio is a tough one to beat. - Mike Kazimer





Visit the high-res gallery for more images from this review





About the Reviewer

Stats: Age: 34 • Height: 5'11” • Inseam: 33" • Weight: 160lb • Industry affiliations / sponsors: None Twenty years deep into a mountain biking addiction that began as a way to escape the suburban sprawl of Connecticut, Mike Kazimer is most at home deep the woods, carving his way down steep, technical trails. The decade he spent as a bike mechanic helped create a solid technical background to draw from when reviewing products, and his current location in the Pacific Northwest allows for easy access to the wettest, muddiest conditions imaginable. Age: 34 • Height: 5'11” • Inseam: 33" • Weight: 160lb • Industry affiliations / sponsors: None

YT's direct-to-consumer sales model is what helped put them on the map in the first place, and the trend of offering a lot of bike for the buck continues with the Jeffsy. The full carbon version is available in three build configurations, with prices ranging from $4,399 to $5,999 USD. There's also an aluminum-framed model available for riders whose budget isn't quite ready for the price of carbon, with prices beginning at $2,699 USD.The CF Comp 1 reviewed here checks in at $4,599 (it's currently on sale for $3,499 - the 2017 version will be $4,299) and comes equipped with a SRAM X1 1x11 drivetrain, and a 140mm RockShox Pike RCT3 paired with a Monarch RT3. Race Face takes care of the cranks, stem, and handlebar, while SRAM's Guide RSC brakes help keeps the speeds under control.The Jeffsy looks like what would happen if you took YT's enduro beast, the Capra, and put it on a strict diet of smoothies and soup for a few months. The overall outlines are similar, but the Jeffsy has a more svelte look, and the brace that runs between the seattube and the downtube on the Capra isn't present on the Jeffsy. This allows for just enough room to squeeze in a pint-sized water bottle, an accessory that's available as an add-on from YT.YT resisted the lure of going wild with internal cable routing, and with the exception of the rear derailleur housing, everything runs along the top of the downtube. It might not be quite as aesthetically pleasing as hiding all the housing inside the frame, but it does make installation and maintenance much less of a hassle.There aren't any ISCG 05 tabs to be seen on the Jeffsy, which means there's no way to run a bashguard, but it is possible to put the front derailleur mounts to good use and run an upper guide in order to eliminate the chance dropping the chain.YT went with their Virtual 4 Link suspension layout for the bike's 140mm of travel, a design that sees the rearmost pivot located on the chainstay, underneath and in front of the rear axle, and a short link that connects the seatstays to the bike's downtube. Like the Capra and the Tues before it, the Jeffsy has a very progressive suspension curve, with a strong ramp up in the later portion of its travel. This also makes the bike work well with a coil shock for riders looking to try something different.The Jeffsy has two geometry choices, which can be changed by flipping the small chip located where the shock is bolted to the seatstays. In the high position the bike has a 67.6-degree head tube angle, while the low setting kicks that back to 66.5-degrees. I'd classify the 445mm reach for a size large as modern, but YT haven't gone too crazy with the numbers either.One notable feature is the difference in chainstay lengths between the large and XL bikes (440mm) and the medium and small frames (435mm). According to YT, this was done in order to preserve the balance of the bike and help maintain the same handling traits between sizes. YT aren't the first company to use this idea - Norco comes to mind as a company that has been doing something similar for a number of years - but it's a trend that makes sense, and it's good to see others catching on.What differentiates a trail bike from an all-mountain bike? These days, that's a good question, especially considering the increasing number of genre-blurring options hitting the market. For me (and I'd imagine for most riders), a good trail bike needs to shine while climbinggoing downhill – after all, if the climbs aren't going to be at least slightly enjoyable, why not lug around something with slacker angles and more travel?Thankfully, the Jeffsy hits the mark, with a very composed and efficient feel while climbing. It doesn't quite have the small bump sensitivity (and the resulting traction) as Yeti's SB5.5 or Trek's latest Fuel EX, but it's not far off, with a satisfying quickness at every pedal stroke. Checking in at a hair under 29 pounds, the Jeffsy's weight is very reasonable, especially considering that the frame is the only part that's made from carbon fiber – a weight conscious rider could easily upgrade select components to drop that number even further.There's a little extra motion with the shock fully open, but it's minimal enough that running it open all the time is certainly feasible. I ended up using the fully open position to gain traction on chunkier, more technical sections of trail, and then ran it in the middle compression setting for smoother climbs. The bike's fit is well-suited for long bouts of climbing, thanks in part to the 74.7-degree seat tube angle (in the low setting), which, combined with that moderate reach number, creates a more upright, rather than stretched out, riding position.There's no shortage of 29ers sporting 130-140mm of rear travel these days, and for good reason – those numbers seem like the sweet spot for creating a bike that can be pedaled all day while still delivering a good time on the descents. That's certainly the case with the Jeffsy, and while its geometry numbers aren't wildly radical, it has a very neutral feel out on the trail, which allows the rider to be the pilot, rather than a passenger hanging on for dear life.In steeper terrain the Jeffsy remained easy to handle, a trait that became especially apparent during a trip to Colorado where I ended up riding some seriously strange trails, ones that were extremely loose (think knee-deep kitty litter), and punctuated with tight, slow speed corners. I managed to make it through without dabbing (or cartwheeling through the spindly trees), partially due to dumb luck, and also thanks to the Jeffsy's ability to wriggle its way through awkward terrain without getting hung up. The relatively slack head angle, and the fact that YT chose to spec a fork with 46mm rather than the more common 51mm of offset, help create a bike that strikes an excellent balance of quickness and composure in the steeps.As composed as it is on technical terrain, compared to the Yeti SB5.5, the Jeffsy doesn't encourage quite the same level of brakes off, bombing down the fall-line. It's like comparing a broadsword to a chef's knife – the Yeti tears the trail apart in one stroke, while the Jeffsy would rather slice and dice, bounding from one feature to the next. Regarding the overall handling, I'd say that Specialized's Stumpjumper 29 is the Jeffsy's closest contemporary, which makes sense considering the geometry and suspension design similarities, although the Jeffsy seemed more resistant to bottoming out from large impacts, and had a slightly poppier feel out on the trail.That playful and peppy nature is due in part to the the Jeffsy's progressive suspension curve, which makes it incredibly well-suited to trails filled with bermed turns, rollers, and jumps. On those types of terrain features the strong ramp up kept the Monarch RT3 in the sweet spot of its rear travel, providing a welcome platform to push into while snapping out of a turn or off the lip of a jump.What about running a coil-sprung shock? I was curious about that too, so when Push offered the opportunity to try running their ElevenSix I took them up on the offer. Of course, the price of that shock is nearly 1/3 of the Jeffsy's entire asking price, but it did allow me to get a feel for how the bike's personality changed with a coil rather than an air sprung back end. The difference was instantly noticeable, and while I hadn't thought the amount of traction was lacking before, the ElevenSix helped keep the rear wheel glued to the ground in rough terrain, making it easier to feel confident charging into rocky, rubble-filled sections of trail.The Jeffsy's sprightly nature was slightly diminished, but the strong ramp up, even with a coil spring, meant there was still plenty of pep left for lofting off of jumps and bounding from one side of the trail to the other. The stock Monarch RT3 holds its own out on the trail, as does the 140mm RockShox Pike, but I can see riders looking to morph the Jeffsy into an even more aggressive machine going the coil shock route, and possibly going with a slightly longer travel fork up front. The good news it that the bike works well with a coil shock, and the 200x57mm dimensions means there are a number of suitable options.I've lost count of how many RockShox Reverb posts I've spent time on over the last few years, and for the most part they've been entirely trouble free. However, every once in a while one shows up that's not up to snuff, and that was the case with the post on the Jeffsy. After only a couple days of riding it developed roughly 20mm of play, squishing down into its travel whenever I sat on it. RockShox took care of it quickly, and the replacement held up for the remainder of the test period without any further trouble, but it's unfortunate that even after the recent redesign the new version of the Reverb still isn't immune to this issue. On a side note, I also wish that the remote was located on the underside of the handlebar rather than on the top.SRAM's Guide brakes are another component that I've had extremely good luck with, but the front brake on the Jeffsy didn't want to play nicely. The lever would occasionally 'stick', refusing to return to its fully extended position without some assistance. This is an issue that would be covered under warranty, and according to SRAM, they've since made changes to the tolerances of the master piston that should make this problem less likely to occur.The Jeffsy comes spec'd with 760mm bars and a 60mm stem on the size large, numbers that will be just fine for some riders, but I'd still like to see wider bars and a shorter stem come as stock equipment; after all, this is a bike that YT claims has “gravity oriented geometry.”Onza's Ibex tires are nice and wide, and they offered up plenty of traction in moderately soft conditions, but the side knobs had a tendency to want to squirm around during hard cornering. Part of this could have been due to the pairing of a 2.4” tire with rims that have a 22.5mm internal width – there's not as much support to keep the sidewall from folding over. The tires also had trouble handling slippery roots, with a disconcerting tendency to slide out unexpectedly. For more aggressive riders, and anyone whose frequently rides in wet conditions, I'd recommend swapping these out.