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First Ride: YT JEFFSY 27

Jeffsy surprised us twice at last year’s launch : first by being a trail bike from YT and second by being a 29er. We’re not among those who have anything against bigger wheels, but YT’s gravity DNA is undeniable and the company sort of has that #26aintdead vibe to it – even though it is and they don’t care. Because at the end of the day, what they DO care about is building good bikes that are fun to ride, and in the case of Jeffsy the trail/all-mountain bike, they felt that the 29-inch wheel was the best tool for the job at hand. What, then, is Jeffsy 27 doing here? That’s what we headed down to Malaga, Spain to figure out.

YT Jeffsy 27 Highlights

  • Travel: 150mm F/R (160mm on CF Pro Race)
  • Alu or carbon
  • V4L rear suspension (Horst Link)
  • Pressfit BB92
  • Boost rear axle spacing
  • Internal/external cable routing
  • Integrated chain suck guards
  • Availability: now-April 2017 (depending on model)

Initial Impressions

Aside from the size of the wheels, you’d be hard pressed to tell the difference between a Jeffsy 29 and a Jeffsy 27. They share the same frame layout, but there’s more at work here than meets the eye. To understand the changes, we have to first understand why Jeffsy 27 came to be.

Southern Spain. What a place to ride bikes!

When YT originally set out to build a trail/all-mountain bike, they had no particular ambition to make it a 29er (in fact it’s fair to say they didn’t even WANT to make a 29er). But in the spirit of designing the best trail bike possible, they tested lots of option and to their own surprise got the best results with 29-inch wheels – and that was that. So why now make a 27.5-inch version then? Chatting to Stefan Willared, CTO and main mad scientist at YT, he offered up a couple of explanations: "First of all, to fill a hole in the line-up. Our Capra has slowly been getting a bit more aggressive with each model year, and there are those who felt that the step up from the 140-mm Jeffsy 29 to the 170-mm Capra was too big. Second, there are people who simply don’t want to ride a 29er."

"Second, there are people who simply don't want to ride a 29er."
Stefan "Willie" Willared with his latest creation.
"I'm telling you, size doesn't matter."

The second point is self-explanatory, and there is nothing wrong with making a product that people are asking for. However, rather than ignore the first point by slapping on a pair of smaller wheels and calling it good, YT gave Jeffsy 27 just a bit more brawn: longer reach, slacker head angle, and a 10-mm bump in travel (to 150mm). Small changes, but it all adds up and Jeffsy 27 has found itself on the aggressive side of All-Mountain as a result. Markus Flossmann, YT’s founder and CEO said the same thing:

"We tried to make a trail bike, but dammit, looks like we made another enduro bike again. Hate it when that happens!"
YT is all about the Good Times.

YT was a bit late to the long reach party, both the Capra and the Jeffsy 29 were fairly conservative in this aspect of their geometry. With an additional 15-mm of reach and an XL in the line up from day 1, those days are in the rear view mirror now – the XL Jeffsy 27 offers a full 480-mm of reach and 1224-mm of wheelbase. With a head angle of 66 degrees (in the low setting), Jeffsy 27 should be well-equipped to deal with pretty much any trail.

At 2599 EUR, the AL One offers stonking good value.


YT’s “V4L” rear suspension (a Horst Link layout) has always been among the more progressive on the market, and this is also true in the case of the Jeffsy 27. The anti-squat characteristics were carefully chosen to balance good pedaling characteristics with freedom of suspension movement, and much like they did with regards to progressivity, YT erred on the downhill side of the equation here too.

The chain stays vary in length with the frame size, which YT says helps keep the handling consistent between the different sizes. At 430mm for a size S or M, or 435mm on the L and XL the chain stays are short but not super short (and 5mm shorter than the equivalent sizes on the Jeffsy 29, for reference). A “Flip Chip” on the seat stays allow you to alter the BB height by 10mm and the head angle by one degree (66-67).

Progressive and confidence-inspiring, V4L is easy to get along with.
Moving to metric shock sizing opened the door for the excellent RockShox Deluxe.

Looking closer at the frame, we also note the move to metric shock sizing (for the FOX-equipped models, YT is one of the first manufacturers to take delivery of metric versions of certain rear shocks from the foxtail crew). The rear axle and crank spacing are boost-ed, but the fork is not. YT used boost spacing in the rear as a means to make room for the tires and the short chain stays, but they don’t feel like there’s enough benefit to going boost up front “just for the sake of it.” As for aftermarket wheels, most major vendors offer the ability to mix and match front and rear hubs, so we don’t feel like this choice will cause any real headaches down the road either.


There are plenty of nice details on the frame, the integrated “chain suck guards” are a particularly welcome addition on the carbon frames. The internally routed cables have integrated guides to keep noise down and make wrenching on the bikes easier, and there is a front derailleur mount as well as space for a (small) water bottle. The line-up features 4 carbon models and 2 alu models, with the top of the line CF Pro Race model getting an additional bump in travel, up to 160mm front and rear (by using a rear shock with a longer eye-to-eye measurement).

CF Pro Race
CF Pro Red
CF Pro Black

On The Trail

We elected to ride the RockShox-equipped CF One, positioned as a bike that is “easy to set up with enough performance on tap to cater to beginners and pros alike.” We took YT’s word for it, set our sag and hit the trails. The Jeffsy 27 felt light and playful from the start, and it didn’t take us long to feel right at home. The bike inspires confidence, handles with poise and quickly had us looking to get off the brakes and pick up speed whenever possible.


The Jeffsy 27 rolls fast and responds well to pedal input. It is not as tight and ultra-responsive as a 130mm bike for example, but it still moves out with speed whenever you hit the cranks, helped by a decent amount of anti-squat, good frame stiffness, and a solid part spec. Much like big brother the Jeffsy 29, the bike isn’t among the absolute best pedaling bikes out there, but more than good enough for any epic rides you might want to consider.


For earning your turns, the Jeffsy 27 turned out to be a great companion. We tackled quite a few long and tough climbs during our time in sunny Southern Spain, including a grueling adventure in the middle of a surprise and certainly not very sunny snow storm.

"Come to Sunny Spain," they said, "it'll be fun," they said...
Whoever heard of Snowy Spain?

We were assured by our gracious hosts, that it was most unusual for the region and the season - be that as it may, it definitely wasn’t the bike that made it hard going that day. We could nitpick and wish for another degree of seat tube steepness, but to be completely fair this tester has long legs and almost always feels that way (and the Flip Chip is there for those who really want to commit to a more climb-friendly geometry).

YT's EWS ace Bryan Regnier was on hand to give the new bike a good thrashing. You'll see him race it at select venues this year too.

Stepping down to 150mm hits a real sweet spot in terms of balance between pedaling efficiency, playfulness, and “shred-ability”, and it’s this sweet spot that YT’s latest creation seems to have landed on – dead center.

Point the Jeffsy 27 down the hill, and it becomes apparent that although it’s classified as a trail or all-mountain bike, it can certainly do duty above and beyond its pay grade. Within the limitations of the 150mm of travel, we never had a feeling of being in over our heads, including on a bunch of very steep, rough, loose, and technical trails. The extra reach and slack, 66-degree head angle add confidence when loading up the front, and the bike feels roomy and stable over the rough stuff.


The Jeffsy 27 is equally at home in the air, and thanks to its light weight and responsive nature it likes to play around. Go ahead and hit those natural little doubles, the bike bunny hops with ease and is always up for shenanigans. The progressive nature of the suspension adds support and provides a bottomless feel that also helps give the rider confidence. Much like on YT’s Capra, the flip side of all that progressiveness is a bike that can sometimes feel a bit harsh over fast, mid-sized hits.


So who is the Jeffsy 27 for? If you always wanted a YT trail bike but not the 29-inch wheels, Jeffsy 27 is obviously for you. As for mountain bikers in general, we’ve noticed a lot of enduro bikes creeping towards 170mm travel and even more, and that trend looks set to continue with coming product launches as well. We always have a tendency to want more of everything, but for a vast majority of riders, 170mm is simply too much travel. Stepping down to 150mm hits a real sweet spot in terms of balance between pedaling efficiency, playfulness, and “shred-ability”, and it’s this sweet spot that YT’s latest creation seems to have landed on – dead center.

Build Kits and Pricing

YToperates a direct-to-consumer distribution model, and as such, the build kits all offer extra-ordinary value. You’d be hard pressed to find ANYTHING to upgrade on the top of the line models, and the rest of the range is equally impressive in terms of the bling-per-dollar ratio. YT also likes to “spread the love around” a bit when it comes to picking their suppliers, and they have continued to diversify when kitting out the Jeffsy 27. For example, there are dropper posts from Race Face and e*thirteen now present on certain models, and mix-and-match drivetrains involving those two companies as well as both SRAM and Shimano. We have little criticism to offer on the choices made, and we were able to test quite a few of the new components, albeit briefly, with good results.


One point of interest is the FOX Performance Elite series suspension found on the second-from-the-top CF Pro model. At first glance you might wonder why such a high-end bike doesn’t get the Factory series suspension found on the CF Pro Race, but it’s actually not that far off: the Performance Elite series (not to be confused with the “regular” Performance series) features the exact same internals as the Factory series, just the Kashima coated stanchions are missing.

Thomas Stoehr, Chief Enforcer of Good Times with the FOX Performance Elite-equipped Jeffsy 27 CF Pro.

Another interesting point is SRAM’s Eagle, notably the absence thereof on the top-of-the-line CF Pro Race. But the secret is in the name: the Pro Race bike was put together with racing in mind, and YT felt that the 9-44T e*thirteen cassette makes for a more compact drivetrain, and that racers would be more than willing to give up a tiny bit of range in return. The e*thirteen cassette offers up 488% of range compared to Eagle’s 500%, a marginal difference by any standard. For the bird lovers out there, Eagle IS found on the CF Pro.

Ready to race.

Our only real complaint would be the 760mm handlebars found on certain builds. As we always say: you can cut but you can’t make a bar wider, and although Jeffsy 27 may be a trail bike by name, it certainly deserves a wide bar by nature.





Pricing (European):

Jeffsy 27 CF Pro Race: 4,499 EUR
Jeffsy 27 CF Pro: 3,999 EUR
Jeffsy 27 CF One: 3,399 EUR
Jeffsy 27 CF Two: 3,399 EUR
Jeffsy 27 AL One: 2,599 EUR
Jeffsy 27 AL Two: 2,099 EUR

For pricing in other geographies, point your browser at and select the appropriate region.



The new Jeffsy 27 launches today. For more information, head on over to .

About The Reviewer

Johan Hjord loves bikes, which strangely doesn’t make him any better at riding them. After many years spent practicing falling off cliffs with his snowboard, he took up mountain biking in 2005. Ever since, he’s mostly been riding bikes with too much suspension travel to cover up his many flaws as a rider. His 200-pound body weight coupled with unique skill for poor line choice and clumsy landings make him an expert on durability - if parts survive Johan, they’re pretty much okay for anybody. Johan rides flat pedals with a riding style that he describes as "none" (when in actuality he rips!). Having found most trail features to be not to his liking, Johan uses much of his spare time building his own. Johan’s other accomplishments include surviving this far and helping keep the Vital Media Machine’s stoke dial firmly on 11.

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