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YT JEFFSY 27 First Ride – all Details & Riding Impressions

YT just dropped their latest 2017 bikes amidst loud cries of excitement in the industry and just a few days later they’ve already taken it even further with the launch of the JEFFSY 27, a potent trail bike that channels some classic YT genes. So what distinguishes the 27 from the JEFFSY 29 and the Capra and how will the JEFFSY 27 ride on the trails?

‘Size doesn’t matter!’ proclaimed YT with the drop of the JEFFSY 27. So what does count then? Clearly, it’s all about the ability to get stoked on the trail, regardless of whether you’re on a 29er or rolling on 27.5″ wheels. As the name suggests, the new YT JEFFSY 27 is on the smaller wheels, but – depending on the build spec – you’ll get one or two additional centimetres of travel as well as optimized geometry for the wheelsize.

YT Jeffsy 27 CF Pro Race 2017 | 160 mm / 160 mm | € 4,499

The YT JEFFSY 27 and its Frame

Coming with an aluminium or carbon frame and in four different sizes, all of the JEFFSY 27 models (excluding the top-of-the-line CF PRO Race) have 150 mm front and back travel. Given the bigger hub on the top-end model’s rear shock (230 mm x 65 mm instead of 230 mm x 60 mm) they’ve managed to weasel 160 mm at the back and a long-travel fork with 160 mm. In keeping with YT Bikes’ signature style, all of the rear shocks are built into their Virtual 4-Link (V4L) rear concept with its signature progressive spring rate for the ultimate high octane fun on the trails. Unlike the 29er, the 27 has internally routed gear cables. It’s nice to see that YT have kept the brake cable external, which makes it easier to change. As expected from YT, the JEFFSY 27 flaunts a superb finish, all of the current standards and has space for YT’s own Thirstmaster 3000 bottle cage.

The top-of-the-line CF PRO RACE hands over rear suspension duty to a FOX FLOAT X shock with 160 mm of travel.
Much more than just superficially reminiscent of the 29er, the JEFFSY 27 has the same adjustment option in the seatstay to alter the geometry. We never got round to using it, preferring to ride the JEFFSY in the slacker setting the whole time.
The JEFFSY 27 has space for YT’s in-house-designed bottle cage, the Thirstmaster 3000, which comes with a 500 ml bottle.
Unlike the 29er, the cables for the shifters and dropper post run internally through the frame.
Awash with carbon: even the rocker is made of this sleek and lightweight material.
You can mount 180 mm rotors on the back wheel without the need for an adaptor – nice! The rear axle standard is 148 x 12 mm here.
The top-of-the-range CF PRO RACE has a plush 160 mm-travel fork, while the rest of models tick along nicely with 150 mm at the front.

YT JEFFSY 27 Geometry

In terms of geometry, the JEFFSY 27 seems to have it dialed, ticking the boxes for a sorted and potent trail bike. The 460 mm reach (size L frame) is pretty long, the head angle is relatively slack at 66-67° and there’s an optimized lowering of the bottom bracket (15-5 mm). For the pursuit of better weight distribution, the 430 mm chainstays haven’t been overly trimmed. In the same vein as the 29er model, the 27.5″ JEFFSY also has adjustable geometry settings.

Size S M L XL
Seatpost 410 mm 450 mm 480 mm 520 mm
Top tube 573 mm 602 mm 625 mm 648 mm
Head tube 95 mm 110 mm 125 mm 135 mm
Head tube angle 66°-67° 66°-67° 66°-67° 66°-67°
Seat tube angle 74.5°-75.5 74.5°-75.5 74.5°-75.5 74.5°-75.5
Chainstays 430 mm 430 mm 435 mm 435 mm
BB height 341 mm – 350 mm 341 mm – 350 mm 341 mm – 350 mm 341 mm – 350 mm
Wheelbase 1138 mm 1169 mm 1200 mm 1224 mm
Reach 415 mm 440 mm 460 mm 480 mm
Stack 584 mm 597 mm 611 mm 620 mm

YT JEFFSY 27 CF Pro Race Specification

Much like the recently presented 2017 models from YT, the JEFFSY 27 comes with a wholly sorted spec that appears to be primed for the trails. The top-end CF PRO RACE has sidestepped a SRAM X01 Eagle drivetrain (as has the 29er), for the following reason: “The Race models prioritise performance and weight, and this is where the mix of RaceFace NEXT SL cranks and an E13 cassette save around 100g when compared to a complete SRAM drivetrain with an almost identical range of gears” explained YT head designer Stefan Willared. The JEFFSY comes in four carbon and two aluminium models, and each frame material comes with one double-chainringed model, while the rest are all 1x gearing set-ups.

“The E13 TRS+ cassette has a sufficient 9-44 gear ratio and saves 100g in weight with the lightweight Race Face Next SL cranks instead of a SRAM Eagle drivetrain,” says Stefan Willared.
The Renthal cockpit is well-tuned to the JEFFSY 27’s look and performance. The Race Face Turbine bars on the other models are only 760 mm in width, and we reckon these could be wider.