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2023 YT Industries

Jeffsy Primus 24

A 24″ aluminum frame mountain youth bike with high-end components and sram g2 r hydraulic disc brakes.
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Manufacturer Price

$1,999
Weight27.8 lbs  
FrameAluminum
SuspensionFull, 130 / 130mm
ForkManitou Machete JUNIT
ShockManitou
Wheels24″ Aluminum
Drivetrain1 × 11
GroupsetX1, NX
BrakesSRAM G2 R Hydraulic Disc
SeatpostDropper
Where to Buy
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Insights
Ride Feel

Based on frame geometry and build specs.

Handling
nimblestable
Jeffsy Primus 24
Other Mountain Youth bikes
Gearing

A bike with lower gearing will be easier to ride up steep hills, while a higher top end means it will pedal faster down hills.

Lowest gear

(climbing)

19 mph

Jeffsy Primus 24

Highest gear

(descending)

Spec Level

Based on build material and quality level of the frame, fork, wheelset, groupset, suspension system, and more.

Compare the full Jeffsy model range

View Comparison
Sizing
One Size

4'5" – 5'0"

Rider Fit Notes

None yet.

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Reviews

Summary

The YT Industries Jeffsy is a highly capable and versatile enduro bike, praised for its gravity-hungry nature, fast and confident riding, and exceptional value. It excels in both climbing and descending, with a suspension system that offers great traction and support. The bike is often compared to top models like the Santa Cruz Hightower and Canyon Spectral, standing out for its playful yet stable handling.

Pros
  • Incredibly capable and fun

  • Exceptional value

  • Modern geometry

  • Great suspension performance

  • Versatile for all-mountain riding

Cons
  • Pedal bob on long climbs

  • Limited water bottle space

  • Underpowered brakes on some models

  • Press-fit bottom bracket issues

  • Somewhat vague-feeling climbing characteristics

Key Quotes
The YT Jeffsy turned our usual value conversation on its head.
Beta logoBeta
With the YT Jeffsy Base 29, you get an incredibly capable bike at an exceptional value.
BIKE Magazine logoBIKE Magazine
The Jeffsy is an excellent jack of all-mountain trades.
Bike Perfect logoBike Perfect
This is about as close as you can get to the ‘one bike for all’ ideal for how a lot of modern mountain bikers ride.
Bikerumor logoBikerumor
The new Mk III Jeffsy feels more capable but just as much fun as ever
BikeRadar logoBikeRadar

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Mountain Bike Action
BIG THINGS COME IN SMALL PACKAGES - YT JEFFSY PRIMUS JUNIOR REVIEW - Mountain Bike Action Magazine

Nov 2024 · Nelson

With a value spec of workhorse components, and putting higher-end components where it matters, this is a hard package to beat.

Highs
  • Top-notch paint quality and finish

  • Cleanly designed internal cable routing

  • V4L suspension design for great traction and efficient climbing

  • SRAM SX Eagle 12-speed with a broad gearing range

  • SRAM G2 R brakes with adjustable reach levers

  • YT Postman 100mm dropper seatpost enhances riding experience

  • Maxxis DHR II tires for excellent cornering and traction

  • Great value with workhorse components and higher-end components where it matters

Lows
  • SRAM SX Eagle drivetrain requires regular adjustment

  • 760mm-wide aluminum handlebar too wide for most kids

  • Significant seal friction in forks and shocks for lighter riders

  • Stiff 35mm aluminum handlebar may exacerbate feedback and control issues

Read Review

Bike Perfect
YT Jeffsy Core 4 review – MK3 version of the excellent all-mountain bike

Aug 2024 · Rich Owen

Rich Owen was a big fan of the previous Jeffsy, so what does he think of the latest Core 4 version after months of using it as his daily driver?

Highs
  • Excellent ride-anywhere bike

  • Updated frame with internal storage

  • Sorted component package with wireless SRAM T-Type drivetrain

  • Rides lighter than its actual weight

  • Useful internal and external on-bike storage

Lows
  • Matte black carbon finish is easily scratched and scuffed

  • Not the biggest internal storage opening

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off.road.cc
YT Industries Jeffsy Mk3 Core 4 mountain bike review

Jul 2024

The YT Jeffsy Mk3 Core 4 is a capable all-mountain bike which, thanks to its spec, has a bias towards descending but is equally able to climb. While the spec is hard to argue with and the value for money is excellent, it's worth paying attention to the frame sizing and geometry to get the ride you want. The bike could be improved further with a longer dropper post and a slacker head angle but YT has done a good job continuing to polish the already excellent Jeffsy.

Read Review

Singletrack World
YT Jeffsy Core 4 review

Mar 2024 · Ben Haworth

The YT Jeffsy Core 4 is a bike that arrives in a box that is not quite perfect out of the box. BUT... there is loads of potential here.

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Pinkbike
Video: The All - New YT Industries JEFFSY

Oct 2023 · YT Industries

This is the next evolution of a proven formula, and with it, we go above and beyond in our pursuit of Trail Excellence..

Read Review

BikeRadar
YT Jeffsy Core 4 review

Oct 2023 · Robin Weaver

The new Mk III Jeffsy feels more capable but just as much fun as ever

Highs
  • Well-balanced geometry

  • Suspension feels active but supportive

  • Very capable on the terrain I tested it on

Lows
  • Freewheel pickup could be quicker

  • Front tyre not the best in soft mud

Read Review

Loam Wolf
First Ride: The New YT JEFFSY MK3

Oct 2023

YT Industries has released the third generation of their do-it-all trail bike, the Jeffsy MK3. Check out our first ride impressions here.

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

Apr 2023 · Jessie-May Morgan

The YT Jeffsy Primus 27 steps up an affordable 150mm all-mountain bike for riders 135cm to 165cm tall (or 4’5” – 5’5”); priced at $2,399

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Geometry
Specs
Build
Fork

MANITOU MACHETE JUNIT, 24“ | 130 mm Travel | 110 x 15 mm Axle | Offset 42 mm Adjustable Rebound, Air Pressure

Travel130mm

Spring TypeAir

Shock

MANITOU MCLEOD, Shock Length: 190 mm | Shock Stroke: 40 mm ≙ 130 mm Travel 4-way Adjustable Compression, Rebound, Air Pressure

Travel130mm

Headset

ACROS AZX-576, High Cap | 2 Spacer 5 mm

Stem

SDG JR, Length 40 mm | 31,8 mm Clamp | Rise +/-3°

Handlebar

SDG SLATER, Width 650 mm | Rise 20 mm | 8° Back Sweep | 5° Up Sweep

Saddle

YT Custom | Width 122 mm

Seatpost

YT POSTMAN V2, Ø 31.6 mm | 100 mm | Std. Remote I Adjustable drop 20 / 10 / 5 mm

TypeDropper

Grips

SDJ SLATER JR, Lock On

Groupset
Rear Derailleur

SRAM NX, 11-speed

Crank

SRAM X1, Crank Arm Length 155 mm | 30 T | DUB

Shifters

SRAM NX, 11-speed

Cassette

SRAM PG1130, 11-42T | 11-speed

Brakes

SRAM G2 R, Rotor CENTERLINE Ø front 160 mm / rear 160 mm Adjustable Reach

TypeSRAM G2 R Hydraulic Disc

Wheels
Rims

SUNRINGLÉ DUROC 30, Aluminum Rims 24“ | Inner Width 26 mm | Front Hub 110 x 15 mm | Rear Hub 148 x 12 mm | Freehub HG

Tires

FRONT: MAXXIS MINION DHF I REAR: MAXXIS MINION DHR II, Front: Tire Size 24“ x 2.4 I EXO Casing I 3C MaxxTerra Compound I Tubeless Ready I, Rear: Tire Size 24“ x 2.3 I EXO Casing I Dual Compound I Tubeless Ready

Rider Notes
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First added April 27

Last updated July 13

Not listed for 694 days