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YT Jeffsy v3 Lands with Less Travel, More Trail Capability, More Friendship

2023 YT Jeffsy mk3 trail bike, 145mm all-mountain bike, Cory riding in Forest of Dean
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While it looks quite similar on the outside, this new YT Jeffsy’s 3rd generation transforms quite a bit the deeper you look at it. Jeffsy has always been YT’s action-packed happy-medium bike – in between their shorter- and longer-travel mountain bikes. But now they fully embrace versatility with a new Jeffsy mk3 that dials-in that sweet spot of mid-travel suspension, with refined geometry that’s now more confident going uphill or down.

2023 YT Jeffsy mk3 mid-travel trail mountain bike

Again, it’s a new bike that aims to be the mountain biker’s best friend.

Shifting a bit in how YT talk about it, what was once an all-mountain bike is now a trail bike. But really, that’s less to say about Jeffsy itself, and more about how we ride trails now. And how capable modern mountain bikes can be. With more mountain bikers riding more technical trails, trail bikes have stepped up to the challenge.

2023 YT Jeffsy mk3 trail bike, 145mm all-mountain bike, Core % CF complete
(Ride Photos/YT)

The new Jeffsy is a bit smaller of a bike overall, but it really does feel more capable than ever in this latest iteration. Quick local singletrack laps. All day trail rides. Even the occasional trip to the bikepark. There’s not a lot this new trail bike can’t do.

2023 YT Jeffsy mk3 trail bike, 145mm all-mountain bike, Cory ride testing

I got the chance to spend a few days riding the new Jeffsy on wet English & Welsh trails a few weeks back. So stay tuned for a First Rides Review coming soon. In the meantime, let’s dive into the details…

So, what’s new?

Big wheels, but less travel!

2023 YT Jeffsy mk3 trail bike, 145mm all-mountain bike, angled
(Detail Photos/Cory Benson)

The new 2023 YT Jeffsy mk3 simplifies things by going 29er-only in this new generation. At the same time, it also dials it back a bit to 145mm of rear wheel travel. Vs. 150mm on the mk2 29er or even 160 on mk2 27.5″ bikes. And the new bikes pair with 150mm travel forks. That really drops it more in a logical middle ground between YT’s 130mm Izzo and their 170mm travel Capra enduro bikes.

2023 YT Jeffsy mk3 trail bike, 145mm all-mountain bike,V4l suspension detail

But while travel is slightly reduced, YT refined the V4L four-bar suspension kinematics. Newly improved support at the bike’s deep 30% sag setting improves pedaling efficiency on the flats and climbs – without making the bike harsh over small bumps. Then, later in the travel, increased end stroke progression still means a more bottomless, supportive feel – even with that 5mm less travel at the rear wheel.

The new Jeffsy is actually more capable as ever, retaining its gravity bike inspiration combined with newly optimized acceleration.

Contemporary trail geometry

2023 YT Jeffsy mk3 trail bike, 145mm all-mountain bike, updated geometry

The geometry of the gen3 Jeffsy is also refined to complement that suspension tweak. A degree slacker head angle and 5mm longer frame Reach accompany the slightly shorter travel & snappier ride. While the steep seat angle, frame Stack, BB drop & size-specific chainstay lengths all effectively remain unchanged for a familiar ride.

There’s also still the same flip-chip at the lower shock mount for quick & easy tweaks to the bike’s geometry to tailor it to your own style of trail riding.

New tech features, too

2023 YT Jeffsy mk3 trail bike, 145mm all-mountain bike, complete

The new Jeffsy still quietly includes two levels of carbon construction – high-end ultra-high modulus fibers on the top Core 5 only, with regular hi-mod for the other carbon specs.

YT Jeffsy gen3 alloy trail bike, mid-travel 145mm aluminum mountain bike, frame detail

But there’s also then an all aluminum frameset to keep the entry-level price point reasonable. Both CF & AL feature the same exact geometry, and a move to UDH for universal drivetrain or transmission fits.

The new Jeffsy now adds an internal storage glovebox for those carbon bikes. It’s just below the forward shock mount, but separate from the bottle cage for security. And yes, YT sweated the details. They developed a secure latch and double-lip seals on the lid to be sure it stays in place and water stays out. Inside, a couple of neoprene bags (one up & one down) offer plenty of tool & spares storage, while keeping everything rattle-free.

2023 YT Jeffsy mk3 trail bike, 145mm all-mountain bike, non-driveside

Underneath that, there’s a mount for an updated side-load cage that fits a 620ml water bottle to keep you hydrated, or most other standard bottles, too. Then, new external storage mounting bosses under the toptube will mount trailside spares for easy access on all bikes. Or even to carry a spare layer like I did,

Tech details

2023 YT Jeffsy mk3 trail bike, 145mm all-mountain bike, head tube

The new Jeffsy keeps the angular headtube and low-key graphics that are consistent through the YT family. Although the bike does slightly realign its lined internal cable routing with new ports along the side of the headtube.

The bike again features updated molded frame protection under the downtube, and wrapping around both the seatstay and chainstay. The downtube protector especially now sits just off the frame with a foam-backed insert to keep your ride quiet, and truly protect the carbon frame from rock strikes.

YT Jeffsy mk3 – Pricing, Options & Availability

2023 YT Jeffsy mk3 trail bike, 145mm all-mountain bike, groups ride
(Photo/Cory Benson)

YT sees the new Jeffsy gen 3 as the ultimate mountain bike for everyone from entry-level MTB shredders to hardcore trail riders. So, they build it in 2 alloy and 3 carbon models across a wide price range to fit all budgets. All in a wide 5 size range (S-XXL) with adjustable geometry.

Alloy Jeffsy

On the aluminum front, the new YT Jeffsy Core 1 AL is the absolute entry-level at $2800 / 2500€ with a SRAM SX/NX Eagle mix and RockShox Lyrik Base/Deluxe Select+ suspension in Drip Yellow. The Jeffsy Core 2 AL keeps that same alloy frame in Frost Blue, but gets a hard to argue with spec for $3300 / 3000€ with SRAM GX mechanical, Code R brakes, Fox 36/Float X Performance tier suspension, and DT M1900 wheels.

Carbon Jeffsy

2023 YT Jeffsy v3 carbon trail bike, mid-travel 145mm mountain bike, Core 3
2023 YT Jeffsy Core 3 CF

Stepping up to the carbon frameset at $4300 / 4000€, the Jeffsy Core 3 CF gets the same spec as the top alloy bike, here in Pale Green. So, a thousand bucks premium to upgrade to carbon.

Then at $5500 / 5000€, the Jeffsy Core 4 CF goes wireless with a SRAM GX AXS T-type transmission, then a RockShox Lyrik Super Deluxe Ultimate suspension combo, Code RSC brakes, and premium alloy Crankbrothers EN 2 wheels… in Crimson Red. Lastly, the top tier YT Jeffsy Core 5 CF at $6500 / 6000€ features a SRAM X0 AXS transmission build, Fox Factory suspension, Code RSC HS2 brakes, and a Crankbrothers EN 3 wheelset… in Space Blue.

2023 YT Jeffsy mk3 trail bike, 145mm all-mountain bike, trailside

All spec levels get trusted tubeless Maxxis Minion DHF/DHR tires with EXO+ casings and YT Postman V2 droppers. They also all include a Black Magic paint option for those who prefer subtlety.

Get ’em all direct from YT now.


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6 months ago

Man….these bikes are really all starting to look so similar….. Cannondale Habit anyone?

6 months ago
Reply to  Andrew

Except you can run your regular parts on this bike. Jeffsy is the best trail bike on the market fight me.

6 months ago
Reply to  Andrew

The laws of physics are the same for everyone, so it follows that as MTB becomes a mature sport the bikes will look more and more alike. This is a similar layout as a Cotic (save the chainstay pivot) or a Guerilla Gravity (RIP) or a Canyon. No point designing a sub-optimal frame for the sake of looking different.

Deputy Dawg
Deputy Dawg
6 months ago

Looks like a great bike, if a little shy on bottle space.

Absolute genius on YT’s part to route the cables through the frame instead of the headset.

Let’s hope this trend catches fire! 🙂

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