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YT Jeffsy Primus 27 is an Affordable All-Mtn Bike for Shorter Riders

yt jeffsy primus 27 small 150mm travel full suspension bike
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YT is extending its line of full suspension mountain bikes for growing riders, adding the YT Jeffsy Primus 27. It joins the Jeffsy Primus 24 and Jeffsy Primus 26, offering another rung on the size ladder for developing Young Talent. The Jeffsy Primus 27 is aimed at folk between 135 cm and 165 cm tall (or 4’5” – 5’5”), making it a legitimate option for shorter adults, too. Indeed, it runs the very same frame as the 2021 YT Jeffsy 275, completed with cockpit and contact point components better suited to the shorter rider.

Speaking of Young Talent… Lennox Zimmermann shows us what’s possible.

YT Jeffsy Primus 27

The YT Jeffsy Primus 27 is essentially a re-positioning of the 27.5″ wheel model of the 2021 YT Jeffsy. It runs the very same aluminum frameset. As such, it boasts 150mm of rear wheel travel paired with a 150mm fork, and an identical geometry. That’s a reach of 422mm, with a seat tube length of 395mm, and a chainstay length of 432mm.

yt jeffsy primus 27
The YT Jeffsy Primus 27 weighs a claimed 15.3 kg with tubeless tires, without pedals and bottle

The Jeffsy Primus 27 sees a geometry-adjusting flip-chip at the lower shock mount, allowing the rider to raise or lower the bottom bracket height, concomitantly altering the head tube angle. In its low position, the Primus 27 has a BB drop of 13mm, and a HA of 65.7°. Full details on geometry can be found below.

What is more noteworthy here, is that the Jeffsy Primus 27 brings the price of this all-mountain bike down to a more budget-friendly £2,499 – but only for shorter riders, of course. That’s £500 cheaper than the comparable Jeffsy Core 2 model, the price of which has risen to £2,999.

Highlights of the Jeffsy Primus 27 build include a 150mm RockShox Lyrik Base Fork, a custom-tuned RockShox Deluxe Select Shock, a SRAM SX Eagle 12-Speed Drivetrain with 11-50T cassette and 165mm cranks, and SRAM G2 R Brakes with 200mm rotors front and rear.

Young Talent, Lennox Zimmermann, does a whip over a table on his Jeffsy Primus 27

It rolls on a Sunringle Duroc Wheelset with 35mm internal diameter rims, seating a Maxxis Minion DHF/DHRII pairing in the EXO Casing. Additional derrière-to-saddle clearance is afforded by a 125mm drop YT Postman Dropper Seat Post topped with an SDG BEL Air 3.0. In the cockpit we see an E13 Base Bar and Stem; the bar is 760mm wide with a 20mm rise, while the stem has a 40mm length.

yt jeffsy primus 27 geometry
YT Jeffsy Primus 27 Geometry

Pricing & Availability

The YT Jeffsy Primus 27 retails at £2,499 / $2,399 USD / $3,349 CAD / 2,399 €, and is available in Nox Blue only. The Jeffsy Primus 24 and Primus 26 full suspension mountain bikes for children remain in the lineup for 2023; pricing as follows. All are sold with a 5-year warranty.

Jeffsy Primus 26Deep Yellow£2,299$2,199$3,099$2,199
Jeffsy Primus 24Lava Red£2,099$1,999$2,799$1,999
The Jeffsy Primus 27 fits both the Thirstmaster 3000 (side entry cage, 0.5l) and Thirstmaster 4000 (Fidlock system, 0.6l). It is possible to fit other side entry cages wit regular bottles in roughly this size, too.


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