Bikes up to 60% offWe monitor over 40,000 bikes daily to find the best prices
Today’s Deals2025 YT Industries
Jeffsy 29 CORE 3 CF
A 29″ carbon frame full suspension trail bike with high-end components.
Compare the full range
Manufacturer Price
$5,299| Weight | 34.8 lbs |
|---|---|
| Frame | Carbon |
| Suspension | Full, 145 / 150mm |
| Fork | RockShox Lyrik Ultimate |
| Shock | RockShox Super Deluxe Ultimate |
| Wheels | 29″ Aluminum |
| Drivetrain | 1 × 10 Electronic |
| Groupset | S1000 Eagle Transmission |
| Brakes | Hayes Dominion A4 Hydraulic Disc |
| Seatpost | Dropper |
Based on build material and quality level of the frame, fork, wheelset, groupset, suspension system, and more.
Compare the full Jeffsy model range
View Comparison5'0" – 5'6"
5'3" – 5'10"
5'7" – 6'1"
5'11" – 6'5"
6'2" – 6'8"
None yet.
Do you have this bike? Help other riders make a decision about which size will work for them by sharing your own size and fit notes.
Summary
The YT Industries Jeffsy is a versatile mountain bike that excels in agility and suspension performance, offering a fun and reliable ride across various terrains. It stands out for its value, with high-quality specs and thoughtful frame details, though some may find its weight and component choices limiting. The bike's geometry and suspension are praised for their balance and capability in both climbing and descending.
Super fun to ride
Excellent suspension
Highly agile
Most affordable bike in the test
Exceptionally quiet ride
Spec could be improved
Heavier than some competitors
Shorter dropper post limits freedom of movement
The YT JEFFSY is the only bike in this test that has already proven itself in a previous comparison.
Enduro Mountainbike MagazineDespite the top-tier spec, the JEFFSY CORE 5 remains the most affordable bike in this test.
Enduro Mountainbike MagazineThe Jeffsy feels like the triumphant return of the real-value trail bike.
Mountain Bike ActionFeedback?
View all reviews
Apr 2025 · Ron Koch
Whether you’re a novice looking for a starter bike packed with value or a seasoned pro looking for a well-rounded, ride-most-anything machine, the Core 2 ticks all the boxes. With a sale price that’s less than $3k, it feels like an incredible deal that won’t last forever, too.
Feb 2025 · Steve Fisher
YT Industries reconfigures their JEFFSY CORE builds for 2025, now offering the mid-range bikes with carbon or aluminum frames.
Feb 2025
Calling these bikes “all-new” might be a stretch, but there's no denying the incredible value and versatility.
Feb 2025 · YT Industries
The Jeffsy range gets the Core treatment, with six options to suit most riders' needs.
Sep 2024
The YT Jeffsy Core 4 has excelled at being an all-round “grab and go” bike, regardless of what gets thrown in its way. Check out our review.
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?
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
Matte black carbon finish is easily scratched and scuffed
Not the biggest internal storage opening
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.
Oct 2023 · Mike Hunger
With the 2024 JEFFSY, YT have unveiled the latest iteration of a true trail bike evergreen, which rolls into the new season with a fresh new look, and 5 different spec options. Here’s how it fared out on the trail.
Intuitive handling suits both beginners and advanced riders
Functional frame details
Top spec at a very fair price
No top-spec alloy variant
Cables aren’t clamped properly
| Fork | ROCKSHOX LYRIK ULTIMATE Travel: 150mm Spring Type: Air |
|---|---|
| Shock | ROCKSHOX SDLX ULTIMATE Travel: 145mm |
| Bottom Bracket | no default description found default |
| Headset | CANE CREEK SERIES 40 |
| Stem | RENTHAL APEX 35 |
| Handlebar | RENTHAL AL2014 |
| Saddle | SDG BEL AIR 3.0 OVERLAND |
| Seatpost | YT POSTMAN V2 Type: Dropper |
| Grips | ODI ELITE MOTION V2.1 |
| Rear Derailleur | SRAM S1000 EAGLE TRANSMISSION |
|---|---|
| Crank | SRAM S1000 EAGLE TRANSMISSION |
| Shifters | SRAM POD CONTROLLER |
| Cassette | SRAM S1000 EAGLE TRANSMISSION |
| Brakes | HAYES DOMINION A4 Type: Hayes Dominion A4 Hydraulic Disc |
| Rims | CRANKBROTHERS Synthesis Enduro Alloy |
|---|---|
| Tires | FRONT: MAXXIS DHF I HINTEN: MAXXIS MINION DHR II |
First added February 25
Last updated June 13