Press Release

YT JEFFSY PRIMUS 24, 26, and Now 27: Small in Size, Big on Performance

YT introduces a 27-inch junior bike for slightly bigger rippers.

April 27th, 2023 – The JEFFSY Primus was created with the smaller gravity-seeker in mind, with size-specific specifications for maximum performance at the hands of young shredders. Initially available in only 24” and 26” options, the JEFFSY Primus now turns the dial to 27”, expanding the height range to 135 cm – 165cm (or 4’5” – 5’5”).


Slotting directly into YT’s founding principles, the PRIMUS range aims to offer Young Talent access to high performance mountain bikes. Not just for lightweight riders, the PRIMUS range is tested to the same standards as big brother JEFFSY, ensuring boundaries can be pushed with full confidence. Now, YT introduces the JEFFSY Primus 27 to the fold.

Action 01 0
Action 04


24 pack

The smallest ride in the PRIMUS lineup still packs a punch with 130mm of travel at both ends. Suspension is taken care of by the Manitou Machete Junit fork and McLeod rear shock – both with custom light weight tunes and compression/ rebound adjustment. The junior-specific SDG Slater bars, grips and SDG Fly seat enhance ergonomics, while the 155mm SRAM X1 cranks, SRAM NX 11-speed shifting, and four-piston G2 R brakes offer a confident and controlled ride. SUN Ringle Duroc 30 wheels keep things rolling with the cult classic Maxxis DHF & DHR II tire combo for increased confidence on the descents.

Gallery 01.jpg?VersionId=9ryE9BfKHmONGPrHa7glgaSYADz9V


26 pack.jpg?VersionId=u

Next up, the PRIMUS 26 comes in 140mm travel, this time with the RockShox Reba fork and Deluxe Select rear shock (and yes, you guessed it – both have custom lightweight tunes). Steering this sender is an E13 base cockpit with ODI grips, and an SDG Bel Air 3.0 saddle rounds up the contact points – the PRIMUS 26 also gets a YT Postman 100mm dropper for little legs too! Drivetrain steps up to a SRAM SX 12-speed derailleur with a 11-50T cassette and 165mm cranks, while wheels and tires are the slightly bigger version of its 24-inch stablemate.

Gallery 01 0


27 pack

New to the range, the PRIMUS 27 comes in hot with 150mm travel, and is capable of everything from all-mountain adventures to bike park sessions. Suspension is handled by the MY23 RockShox Lyrik Base fork with Debonair+ air spring and Rush RC damper, and Deluxe Select rear shock with a custom tune. Following on from the PRIMUS 26, the E13 cockpit with ODI grips features here too, along with a SRAM SX Eagle 12-speed drivetrain and 165mm cranks. Chosen for slightly longer legs, the 125mm YT Postman dropper and SDG Bel Air 3.0 enhance flow and comfort on the trail, while the 27.5” SUNRinglé Duroc 35 wheels are wrapped in Maxxis DHF & DHR II tires for go-to grip in all conditions.

Detail 01

Specs and Geo

24 geo 0
geo 26.jpg?VersionId=B04SJ1eUITFWjZ9cZ.iy.2jS7swHO
geo 27.jpg?VersionId=UMSdTsknRro9pn639

Pricing and Weights

pricing and weights

YT Mill Showrooms & Rolling Circus - Demo a YT

The YT MILL Showrooms in UK, USA and Germany offer test rides for all available models in the YT Core range, all year round. If your location isn’t near a MILL, then the Rolling Circus demo events bring the whole demo fleet to a variety of locations across the US and the UK.

For more Information about YT Industries:

View key specs, compare bikes, and rate the new YT Jeffsy Primus models in the Vital MTB Product Guide.


The Latest