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YT Jeffsy Core 3 Review

A well-rounded 150mm travel 29er with a huge bandwidth at a great price
YT Jeffsy Core 3
Photo: Jason Peters
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Price:  $4,199 List
Pros:  Excellent value, great build for the price, composed and confident descender, super quiet, well-rounded performance
Cons:  A little heavy, not the fastest climber, geometry feels a touch dated, limited water bottle space
Manufacturer:   YT Industries
By Jeremy Benson ⋅ Senior Review Editor  ⋅  Jun 16, 2021
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83
OVERALL
SCORE


RANKED
#9 of 20
  • Fun Factor - 25% 8.5
  • Downhill Performance - 35% 8.7
  • Climbing Performance - 35% 7.7
  • Ease of Maintenance - 5% 8

Our Verdict

The Jeffsy Core 3 is the latest version of YT's popular longer travel trail bike. While other brands have gone to extremes with their geometry, this bike's moderate numbers are the primary reason it is such a well-rounded, versatile, and user-friendly performer. With 150mm of front and rear travel and 29-inch wheels, the Jeffsy can handle just about anything on the descents yet retains more maneuverability and agility than most bikes in this travel bracket. It's a touch heavy, but it's comfortable and relatively efficient on the climbs. We think it's also an impressive value with a fair price, full carbon frame, and quality component specification that is ready to rip straight out of the box.

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YT Jeffsy Core 3
Awards  Top Pick Award    
Price $4,199 List$4,300 List$3,999 List$3,199 List$2,999 List
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Pros Excellent value, great build for the price, composed and confident descender, super quiet, well-rounded performanceHighly adjustable geometry, adaptable for terrain or riding style, SWAT storage, plush suspension, very stable and confident descenderConfident descender, stable at speed, reasonable price, efficient climber for how well it descendsAffordable, versatile, good build for the price, lively and playful, DW-Link suspensionAffordable, quality suspension, excellent tires, solid all-around performance
Cons A little heavy, not the fastest climber, geometry feels a touch dated, limited water bottle spaceOverkill for tame trails, Fox 36 Rhythm fork, moderate weightTall seat tube limits dropper length, a lot of bike for mellow terrain, underpowered brakesHeavier weight, shorter travel-requires skilled rider in super aggressive terrainHeavy, may be overkill for some riders and locations
Bottom Line A well-rounded 150mm travel 29er with a huge bandwidth at a great priceA heavy-hitting longer travel trail bike with an innovative, highly adjustable geometryA longer travel trail bike with respectable climbing abilities that excels at higher speeds and in aggressive terrainJust as versatile, fun, and playful as the carbon version in a more affordable but slightly heavier aluminum-framed packageThe aluminum framed Ibis Ripmo AF is an aggressive trail bike with a reasonable price tag
Rating Categories YT Jeffsy Core 3 Stumpjumper EVO Comp Canyon Spectral 29... Ibis Ripley AF Deore Ibis Ripmo AF NX Eagle
Fun Factor (25%)
8.5
9.3
8.6
8.2
8.0
Downhill Performance (35%)
8.7
9.4
9.2
8.0
9.0
Climbing Performance (35%)
7.7
8.0
7.6
7.9
6.8
Ease Of Maintenance (5%)
8.0
7.0
7.0
7.0
7.0
Specs YT Jeffsy Core 3 Stumpjumper EVO Comp Canyon Spectral 29... Ibis Ripley AF Deore Ibis Ripmo AF NX Eagle
Wheel size 29" 29" 29" 29" 29"
Suspension & Travel Horst Link - 150mm FSR - 150mm Triple Phase Suspension - 150mm DW-Link - 120mm DW-Link - 147mm
Measured Weight (w/o pedals) 32 lbs 10 oz (XL) 31 lbs 14 oz (Large) 32 lbs 5 oz (Large) 33 lbs 3 oz (Large) 34 lbs (Large)
Fork Fox 36 Performance Elite, 150mm Fox 36 Rhythm - 160mm RockShox Lyrik Select RC 160mm Fox 34 Performance - 130mm DVO Diamond D1 160mm
Shock Fox Float DPX2 Performance Elite Fox Float DPX2 Performance RockShox Super Deluxe Select+ Fox Float DPS Performane EVOL DVO Topaz T3 Air
Frame Material Carbon Fiber FACT 11m Carbon Fiber Carbon Fiber Aluminum Aluminum
Frame Size XL S4 (Large equivalent) Large Large Large
Frame Settings Flip Chip Flip Chip and Headtube angle Flip Chip N/A N/A
Available Sizes S-XXL S1-S6 S-XL S-XL S-XL
Wheelset DT Swiss M 1900 Spline, 30mm inner width Roval 29 alloy rims with Shimano Centerlock hubs, 30mm id Race Face AR30 rims with Shimano MT400 hubs Ibis S35 Aluminum rims with Ibis hubs, 35mm ID Ibis S35 Aluminum rims with Ibis hubs, 35mm ID
Front Tire Maxxis Minion DHR II EXO 2.4" Specialized Butcher GRID TRAIL T9, 2.6" Maxxis Minion DHF EXO 2.5" Schwalbe Hans Dampf 2.6" Maxxis Assegai EXO+ 2.5"
Rear Tire Maxxis Minion DHR II EXO 2.4" Specialized Eliminator GRID TRAIL T7, 2.3" Maxxis Dissector 2.4" Schwalbe Hans Dampf 2.6" Maxxis Assegai EXO+ 2.5"
Shifters SRAM GX Eagle Shimano SLX 12-speed SRAM NX Eagle Shimano Deore 12-speed SRAM NX Eagle
Rear Derailleur SRAM GX Eagle Shimano SLX 12-speed SRAM NX Eagle Shimano Deore 12-speed SRAM NX Eagle
Crankset SRAM Descendant 7K 32T Shimano SLX 170mm Descendant 6K DUB 170mm, 32T Shimano Deore M6100 30T SRAM NX Eagle DUB 32T
Saddle SDG Bel Air 3.0 YT Custom Specialized Bridge Comp Ergon SM 10 Enduro Comp WTB Silverado 142mm WTB Silverado Pro
Seatpost YT Postman 170mm (size XL) X-Fusion Manic 170mm (S4/S5), 34.9 diameter Iridium Dropper KS Rage-i 150mm(Large) KS Rage-i 150mm(Large)
Handlebar e13 Plus 35 Alloy 780mm Specialized 6061 alloy, 30mm rise, 800mm width Canyon G5 Riser, 780mm Ibis 780mm Alloy Ibis 780mm Alloy
Stem e13 Plus 35 50mm Specialized Alloy Trail stem, 35mm bore Canyon G5, 40mm Ibis 31.8mm 50mm Ibis 31.8mm 50mm
Brakes SRAM G2 R 4-piston Shimano SLX 4-piston SRAM G2 R Shimano Deore M6120 4-piston SRAM Guide T 4 piston
Measured Effective Top Tube (mm) 638 625 636 630 631
Measured Reach (mm) 490 475 485 475 473
Measured Head Tube Angle 66.5-degrees H/66-degrees L 63-65.5 (adjustable) 65-degrees H/64.5-degrees L 65.5-degrees 64.9-degrees
Measured Seat Tube Angle 77.5-degrees H/77-degrees L 76.9-degrees 77-degrees H76.5-degrees L 76-desgrees 76-degrees
Measured Bottom Bracket Height (mm) 352 H/344 L 340 (adjustable with flip chips) 344 H/336 L 335 340
Measured Wheelbase (mm) 1247 1247 1251 1217 1239
Measured Chain Stay Length (mm) 440 (XL-XXL) 438 (S1-S4) 437 432 435
Warranty Five Years Lifetime Six years Seven Years Seven Years

Our Analysis and Test Results

The YT Jeffsy is a well-rounded longer travel trail bike with a...
The YT Jeffsy is a well-rounded longer travel trail bike with a great build and a reasonable price.
Photo: Jason Peters

Should I Buy This Bike


If you're searching for a well-rounded longer travel trail bike, we think you'd be hard-pressed to find a better value than the Jeffsy Core 3. YT sells direct to the consumer, and they offer complete bikes with excellent builds at super competitive prices that most mainstream brands can't match. In addition to the fair price, the Jeffsy is a versatile bike with a moderate geometry that performs well in most situations and is easy to get along with. While its geometry may not exactly be "cutting edge", it hits a comfortable middle ground and doesn't sacrifice agility or low-speed handling for marginal performance gains elsewhere. Still, this 150mm travel 29er is capable of charging hard on the descents with great stability at speed and it doesn't feel overly bulky or unwieldy at lower speeds or in technical terrain. YT's V4L suspension platform successfully blends good small bump compliance with mid-stroke support and great bottom-out resistance. On the climbs, the Jeffsy is comfortable, handles well, and feels relatively efficient. It's a touch heavy and isn't necessarily the fastest bike up the hill, be we found it capable of climbing anything we put in front of it and long days in the saddle. For the price, the build of this bike is fantastic and helps to enhance its all-around performance and quality feel. It's also shockingly quiet, with no creaks or rattles of any kind coming from it no matter how rough the trail. Perhaps one of the best things about the Jeffsy is that you might actually be able to purchase one. YT's inventory comes and goes, but when these bikes come back in stock they are sold on a first-come-first-served basis. They also sell two other builds, so you can match your new Jeffsy to your budget.

The Jeffsy has a nice, damp, and muted feel over chunky sections of...
The Jeffsy has a nice, damp, and muted feel over chunky sections of trail.
Photo: Jason Peters

The consumer-direct Canyon Spectral 29 CF 7 is a good comparison to the Jeffsy Core 3. The Spectral also rolls on 29-inch wheels and has 150mm of rear-wheel travel, but it comes with a 160mm travel fork and a more progressive (longer and slacker) geometry. The Spectral charges a fair bit harder on the descents and is super stable at speed and confidence-inspiring in aggressive terrain, but it sacrifices a bit in the low speed, technical handling department as a result. If you're an aggressive trail rider who wants to charge hard on the descents, we'd steer you towards the Canyon. If you're seeking a more well-rounded and versatile ride, then the Jeffsy might be more up your alley. The Spectral 29 CF 7 retails for a couple hundred dollars less, but it comes with a lower-end SRAM NX drivetrain and RockShox Select suspension components.

The Specialized Stumpjumper EVO is another interesting comparison. Like the Jeffsy, it rolls on 29-inch wheels and has 150mm of rear-wheel travel. The EVO comes with a 160mm travel fork, and it has a uniquely adjustable geometry so you can really dial it in to your preferences. The Stumpy is much longer and slacker than the Jeffsy and its head angle can easily be adjusted in 1-degree increments between 63.5 and 65.5 degrees. This makes it essentially 3 bikes in one, anything from a versatile trail bike to a full-on downhill shred machine. The Specialized also has SWAT storage in the downtube and the design and details of the bike are very well sorted. If versatility through adjustability is high on your list, the Specialized is definitely the way to go. We tested the Carbon Comp build which cost just slightly more than the Jeffsy Core 3. It comes with a comparable SLX drivetrain and brakes but downgraded suspension in the form of Fox 36 Rhythm fork and DPX2 Performance shock.

The Jeffsy has distinctive lines and a burly, almost over-built feel.
The Jeffsy has distinctive lines and a burly, almost over-built feel.
Photo: Jason Peters

Frame Design


The Jeffsy Core 3 has a full carbon frame with 150mm of rear-wheel travel. YT has employed their Virtual Four Link (V4L) suspension design which is a four-bar or Horst-Link system. The main pivot is situated just above the bottom bracket with pivots on the chainstays just in front of the rear axle and a rocker link attached midway up the seat tube. The frame has an almost overbuilt look and feel with a reinforced head tube junction and beefy chain and seat stays. The frame has molded chainstay and downtube protection, full-sleeve internal cable routing, and room within the frame for a Thirstmaster Fidlock water bottle or a small standard bottle and cage using the included mounting hardware.

The Jeffsy has flip-chips in the lower shock mount to adjust the geometry slightly. The flip-chip adjusts the head and seat tube angles by 0.5-degrees and raises/lowers the bottom bracket by 8mm. Our size XL test bike measured with a 66-degree headtube angle and a 77-degree seat tube angle in the low setting. It has a 638mm effective top tube length and a 490mm reach. The chainstays measured 440mm (435mm on sizes S-L) with a 1247mm wheelbase and 344mm bottom bracket height (low setting). The Jeffsy comes in 5 frame sizes, S-XXL. Our size XL weighed 32 lbs and 10 oz set up tubeless and without pedals.

Design Highlights

  • Available in carbon fiber (tested) and aluminum frames
  • 29-inch wheels
  • 150mm of Virtual Four Link (V4L) rear suspension
  • Designed around a 150mm travel fork
  • Internal cable routing
  • Chainsuck plates to protect the frame
  • Integrated chainstay, seat stay, and downtube protection
  • Adjustable geometry via flip chip
  • Complete builds from $2,999 to $5,199

With 150mm of travel front and rear, a stout frame, nice build, and...
With 150mm of travel front and rear, a stout frame, nice build, and moderate modern geometry, the Jeffsy is a versatile and confident descender.
Photo: Jason Peters

Downhill Performance


The Jeffsy Core 3 is a solid downhill performer that feels comfortable and composed at a variety of speeds and a range of terrain and doesn't require an expert skill level to enjoy. With 150mm of front and rear travel and 29-inch wheels, this bike is stable and fast, yet its somewhat moderate geometry gives it a balanced, well-rounded feel. It isn't necessarily the hardest charging bike out there, but it is user-friendly and we didn't find any situation on the descents that it felt out of place.

The Jeffsy is just as much fun to rip on smooth flow trails as it is...
The Jeffsy is just as much fun to rip on smooth flow trails as it is to blast down some chunk and chunder.
Photo: Jason Peters

When we say the Jeffsy has a moderate geometry, we're comparing it to other new trail bikes with similar travel and intentions. Most bikes in the same travel bracket are now longer in reach and wheelbase, and they have a degree, or more, slacker head tube angle than the Jeffsy's 66-degrees (low setting). For example, the new Canyon Spectral 29 has a 64.5-degree head angle and a wheelbase that's 3mm longer in a size large than our XL Jeffsy. While it may seem a little behind the current longer/slacker trend, we don't think that's necessarily a bad thing. Where some bikes sacrifice low-speed handling and maneuverability, the Jeffsy maintains a bit of agility and doesn't feel unwieldy in tight, technical sections of trail. At the same time, the bike is still long and slack enough to feel stable at speed and confident on steep and rough trails. Sure, some of the longer and slacker bikes might feel more like downhill plow machines, but the Jeffsy's more balanced demeanor gives it versatility that some of those bikes lack. It didn't strike us as the spunkiest or most playful bike around, but it certainly wasn't opposed to a little time in the air or on the back wheel.

We found the Jeffsy to feel calm and collected over high frequency...
We found the Jeffsy to feel calm and collected over high frequency chop, and the bike is amazingly quiet to boot.
Photo: Jason Peters

YT has employed their V4L suspension platform on the Jeffsy. We found it to feel great over small bumps and high-frequency chop, giving the bike a very damp and muted feel. We felt the mid stroke was nice and supportive, providing a bit of pop and never feeling like it was wallowing. Running just under 30% sag, we were able to get all of the rear travel, but never once bottomed it out. Even while testing on steep skidders with log and ladder drops, it handled big hits with composure and just the right amount of progression to give up all the travel willingly without feeling harsh. Additionally, the Jeffsy is unbelievably quiet, and this bike makes virtually no noise other than the tires on the trail surface. YT really did an excellent job with the chainstay protection and internal cable routing to keep it nearly silent and distraction free.

As with every other YT bike we've tested, you get a great build for the price with the Jeffsy Core 3. YT did a great job spec-ing this bike with quality components that are ready to be ridden hard. First and foremost, the Fox 36 Performance Elite fork provides a burly, confidence-inspiring front end with loads of adjustability and the quality Grip 2 damper. At the back of the bike, the Fox DPX2 Performance Elite shock takes care of the rear suspension duties. The cockpit features a sturdy and responsive E13 Plus 35 handlebar and stem combo and a YT Postman dropper (170mm size XL) to get the saddle low and out of the way. The DT Swiss M 1900 Spline wheels are clad with a matched pair of Maxxis Minion DHR II EXO tires in a 2.4-inch width. The wheels have a nice muted ride quality, and the tires have an aggressive tread with excellent cornering and braking traction. The 4-piston SRAM G2 R brakes with 200mm rotors front and rear work okay, but feel perhaps a touch underpowered for this bike.

The Jeffsy doesn't strike us as the fastest climber, but it's...
The Jeffsy doesn't strike us as the fastest climber, but it's comfortable and handles well.
Photo: Jason Peters

Climbing Performance


The Jeffsy Core 3 performs just fine on the climbs. The geometry is well sorted and the suspension design provides a supportive and relatively efficient pedaling platform. We wouldn't call it the zippiest climber, but for those who aren't concerned with breaking records up the hill, the Jeffsy is a comfortable and capable companion.

There's nothing you can't climb on the Jeffsy if you put your mind...
There's nothing you can't climb on the Jeffsy if you put your mind to it. We found the high geometry setting's higher bottom bracket height to be preferred for technical climbing.
Photo: Jason Peters

At 32 lbs and 10 oz, the XL Jeffsy we tested isn't exactly lightweight. That weight combined with the aggressive tread of the Maxxis Minion DHR II tires contributed to it feeling a bit draggy at times, especially on longer paved or fire road climbs. On the trail, the Jeffsy has a more natural feel, still not an uphill rocket ship mind you, but the comfortable geometry, responsive handling, and moderate geometry feel good in most scenarios. The steep seat tube angle lines the rider up right above the cranks for efficient power transfer and an up-top position that is great for tackling technical sections. The cockpit is roomy without feeling too stretched out, and the wheelbase isn't so long that it becomes difficult to handle at lower speeds or through technical uphill puzzles. The 66.5/66-degree (high/low) head tube angle keeps the handling crisp and responsive. Flip chips in the lower shock mount also allow you to adjust the geometry slightly, and we found the high setting's higher bottom bracket to be preferred for super rocky trails to help avoid pedal strikes.

It may be a tad heavy, but the Jeffsy climbs well with good angles...
It may be a tad heavy, but the Jeffsy climbs well with good angles, a quality drivetrain, great tires, and a comfortable cockpit.
Photo: Jason Peters

YT's V4L suspension design provides a nice calm feeling pedaling platform with good small bump compliance and excellent traction in the rear shock's open position. When seated, there's a tiny amount of suspension bob, but not so much as to feel like your precious energy is being wasted. Out of the saddle, the suspension movement is a bit more noticeable but isn't terrible, and we left the shock open on trail and only reserved the compression damping switch for longer paved or fire road grinds.

On the climbs, the build of the Jeffsy Core 3 mostly helps to enhance its performance. The SRAM GX 12-speed drivetrain simply works well with a massive range provided by the 32 tooth chainring and the newer 10-52 tooth cassette. The YT branded SDG Bel Air 3.0 saddle was surprisingly comfortable and proved to be a great place to sit and spin away the miles and vertical while testing. Maxxis Minion DHR II tires front and rear aren't necessarily the fastest rolling, but they do provide loads of climbing traction, even in loose conditions. We weren't too impressed by the freehub engagement of the DT Swiss rear hub. Sure, it works fine, but it does have a somewhat clunky and unrefined feel to it compared to faster-engaging hubs.

Photo Tour


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Value


The Jeffsy Core 3 is an excellent value. The price of this bike increased just slightly while we had it for testing, but it's still more affordable than most other carbon-framed bikes with a similar build. YT's consumer-direct sales model helps to keep the price low, and this full carbon bike is shred-ready straight out of the box. There's definitely nothing that needs to be upgraded to get out and tear up the trails on this well-spec'd and affordable ride.

Conclusion


The YT Jeffsy Core 3 is a longer travel trail bike that combines a competitive price, a great build, and a well-rounded performance. This 150mm travel 29er's moderate geometry is comfortable and helps to enhance its versatility and user-friendliness. We found the Jeffsy to be easy to get along with and it performed well on the climbs and was composed and capable on the descents with an impressive terrain bandwidth.

If you're looking for one bike to do it all, the Jeffsy is a solid...
If you're looking for one bike to do it all, the Jeffsy is a solid choice. Its modern, middle of the road geometry helps make it well-rounded, and it's a great value.
Photo: Jason Peters

Other Versions


YT makes three reasonably priced versions of the Jeffsy including the Core 3 build we tested.

The Core 2 is the least expensive option and an outstanding value at $2,999. It comes with an aluminum frame and a truly impressive parts spec for the price that includes Fox Performance suspension, a SRAM NX Eagle drivetrain, DT Swiss M 1900 Spline wheels, and Maxxis Minion DHR II tires.

The Core 4 is at the top of the range at $5,199 (which is still a very reasonable price for this bike). It has a carbon frame, Fox Factory suspension, carbon cranks, a SRAM XO1 drivetrain, SRAM G2 RSC brakes, and upgraded DT Swiss M 1700 Spline wheels.

Jeremy Benson