The latest YT news

BE THE FIRST TO BE UPDATED

JOIN OUR MAILING LIST NOW

By registering for our newsletter, you acknowledge the privacy statement.

We've added the following to your cart:

Size

Color

Version

Crankbrothers STAMP 7 Large Pedal

Crankbrothers STAMP 7 Large Pedal

$119.99

YT x Peaty's bicycle cleaning kit

YT x Peaty's bicycle cleaning kit

$0.00

Core 5
29
Enduro MTB Magazine Best Buy
Enduro MTB Magazine Best in Test
29
Enduro MTB Magazine Best Buy
Enduro MTB Magazine Best in Test
ALL MOUNTAIN

JEFFSY CORE 5 is an apex predator, and together, you'll take down the wildest trails as a team. At this level, we go all-out in our hunt for Trail Excellence. FOX Factory suspension for pro-level tuning, SRAM X0 Eagle Transmission shifting for unmatched precision, and our highest-end ultra-modulus carbon... this build is optimized for outright performance down to the finest detail. Whether you get your kicks from flat-out speed or kilometers on the clock, CORE 5 is the ultimate wingman for any challenge.

STASH DOWNTUBE STORAGE

Hide your loot on all Carbon frames

RIDER CENTERED GEOMETRY

Putting the rider in focus

THIRSTMASTER 6000

Never go thirsty again!

STASH DOWNTUBE STORAGE

Hide your loot on all Carbon frames

RIDER CENTERED GEOMETRY

Putting the rider in focus

THIRSTMASTER 6000

Never go thirsty again!

Choose Your

Wheels
Color
Size
Core 5

CORE 5

Wheel size
29
Color / Size

Choose Your Wheel Size

Choose Your Frame Size

inch

cm

5'0" - 5'5"

5'4" - 5'9"

5'8" - 6'1"

5'11" - 6'4"

6'3" - 6'8"

Space Blue

Black Magic

This bike has the earliest arrival

All Available Options

See Other Options

$6,499.00

Notify Me!
Total Amount Without Sales Tax:
Enduro MTB Magazine Best Buy
Enduro MTB Magazine Best in Test
Enduro Mountainbike Magazine

Fu** fake friends! With its top-tier spec, sensible frame features and unbeatable price, the YT JEFFSY CORE 5 already looks great on paper. On the trail, it’s exactly that friend everyone should have, encouraging you to do crazy things but at the same time sticking up for you when you most need it – together, you’ll have the best time of your life! The poppy suspension paired with the agile yet predictable handling, make the JEFFSY the undisputed Queen of Fun in this test – a well-deserved Best in Test! Check out the full review on enduro-mtb.com!

Tech + Specs
  • Frame

  • YT STASH INTERNAL FRAME STORAGE

  • TOP TUBE RIVETS

  • Internal Cable Routing

  • Universal derailleur hanger

  • QUICK RELEASE AXLE TOOL

  • THIRSTMASTER 6000

  • RIDER CENTERED GEOMETRY

  • FLIP CHIP

  • Virtual Four Link

  • SIZE-SPECIFIC REAR ENDS

  • THREE FRAMES TO CHOOSE

  • FRAME PROTECTION

  • SEALED BEARINGS

  • HEEL CLEARANCE

  • DOWNTUBE PROTECTION

Frame

YT STASH INTERNAL FRAME STORAGE

Gone are the days of taping a tube to your frame: Beneath the double-sealed, weatherproof lid lies two water-resistant neoprene bags to keep your payload silent, while a separation wall prevents your goods from getting lost within the frame. Sidewall bonding keeps the cables extra tidy, and for total security, we separated the bottle cage from the lid to prevent unwanted movement.

TOP TUBE RIVETS

Tools, check. Spare tube? Check. Why let a mechanical end your ride; use the toptube mounts to ditch the backpack to store your essentials.

Internal Cable Routing

For optimal protection and sleek lines, cables are routed almost entirely through the frame. This bike is a mechanic's dream: Uninterrupted internal tubes provide easy, intuitive cable replacement and eliminate noise for stealthy slap-free riding.

Universal derailleur hanger

This frame is compatible with the SRAM UDH hanger, meaning it can pair with a wide range of drivetrain options, including SRAM Full Mount Transmission rear derailleurs. Sent it too hard? No sweat – these hangers are easily available worldwide.

QUICK RELEASE AXLE TOOL

Stashed neatly into the rear axle, this custom, removable HEX6 tool is always on hand to save the day. The design allows for effortless wheel removal, helping to put you back on track in no time, and is engineered with ergonomics in mind to ensure generous hand clearance. Whether stuck on the trail with a puncture or cramming multiple bikes in the car for a road trip, this tool has you sorted.

THIRSTMASTER 6000

Included with JEFFSY is our Thirstmaster 6000 bottle and cage combo. As our go-to solution for rider hydration, this BPA-free bottle has a 620ml capacity to quench even the driest thirst, and the side-load cage is simple to use, even on the move.

RIDER CENTERED GEOMETRY

The JEFFSY features Rider Centered Geometry, so you can push harder on the trail in total confidence. A roomy reach measurement, slack head angle, proportional seatstay measurements, and a steep, 77-degree effective seat tube work in sync to create a balanced and precise bike. JEFFSY keeps you, the rider, as the focus – It’s your best friend, after all.

FLIP CHIP

Situated at the lower shock mount, the Flip Chip makes it quick and easy to adjust the geometry according to your ride style. This chip is set to low by default but increases the BB height by 8mm and ST/HT angle by 0.6 degrees in the high position. It's your call: Choose high for enhanced agility, precision, and climbing efficiency or low for trail-ripping confidence and a lower center of gravity.

Virtual Four Link

Our V4L suspension technology is award-winning and has seen more than a few podiums in its time. Sensitive off the top, the design provides claw-like traction on loose terrain while remaining supportive through the mid-stroke. The end-stroke ramps up to prevent bottom-out, even on monster jumps, and did we mention the pop? Load up that linkage and let it fly.

SIZE-SPECIFIC REAR ENDS

Proportional seatstay lengths ensure JEFFSY is perfectly balanced. By keeping the front and rear center in check, the ride character is fast, confident, and predictable, for total control when things get hectic.

THREE FRAMES TO CHOOSE

Depending on your weapon of choice, your JEFFSY will feature either a carbon or hand-crafted aluminum frameset. Our carbon fiber frames come in two options: High Modulus and Ultra Modulus. Both materials are equally durable and built for rowdy riding, with Ultra Modulus being the lighter choice.

FRAME PROTECTION

Extensive chainstay and seatstay protection guards the frame from chain slap, while the knobs reduce chain slap noise. All you’ll hear is the adrenaline rushing through your veins and your tires rolling over the trail.

SEALED BEARINGS

In addition to the double-sealed industrial bearings used, all pivot points are equipped with an additional seal to keep water and dirt at bay, protecting the bearings and extending their service life.

HEEL CLEARANCE

Increased heel clearance to reduce friction caused by the shoes rubbing on the frame while riding.

DOWNTUBE PROTECTION

Silence is the sound of speed. More than just robust protection, the extensive frame guards eliminate unwanted noise, keeping you focused on the trail ahead as you descend like a ninja. JEFFSY even goes a step further: Beneath the bolt-on downtube protector lies sound-deadening foam to keep you cruising through those "Oh sh*t" moments without fear.

YT STASH INTERNAL FRAME STORAGE

YT STASH INTERNAL FRAME STORAGE

Gone are the days of taping a tube to your frame: Beneath the double-sealed, weatherproof lid lies two water-resistant neoprene bags to keep your payload silent, while a separation wall prevents your goods from getting lost within the frame. Sidewall bonding keeps the cables extra tidy, and for total security, we separated the bottle cage from the lid to prevent unwanted movement.

TOP TUBE RIVETS

TOP TUBE RIVETS

Tools, check. Spare tube? Check. Why let a mechanical end your ride; use the toptube mounts to ditch the backpack to store your essentials.

Internal Cable Routing

Internal Cable Routing

For optimal protection and sleek lines, cables are routed almost entirely through the frame. This bike is a mechanic's dream: Uninterrupted internal tubes provide easy, intuitive cable replacement and eliminate noise for stealthy slap-free riding.

Universal derailleur hanger

Universal derailleur hanger

This frame is compatible with the SRAM UDH hanger, meaning it can pair with a wide range of drivetrain options, including SRAM Full Mount Transmission rear derailleurs. Sent it too hard? No sweat – these hangers are easily available worldwide.

QUICK RELEASE AXLE TOOL

QUICK RELEASE AXLE TOOL

Stashed neatly into the rear axle, this custom, removable HEX6 tool is always on hand to save the day. The design allows for effortless wheel removal, helping to put you back on track in no time, and is engineered with ergonomics in mind to ensure generous hand clearance. Whether stuck on the trail with a puncture or cramming multiple bikes in the car for a road trip, this tool has you sorted.

THIRSTMASTER 6000

THIRSTMASTER 6000

Included with JEFFSY is our Thirstmaster 6000 bottle and cage combo. As our go-to solution for rider hydration, this BPA-free bottle has a 620ml capacity to quench even the driest thirst, and the side-load cage is simple to use, even on the move.

RIDER CENTERED GEOMETRY

RIDER CENTERED GEOMETRY

The JEFFSY features Rider Centered Geometry, so you can push harder on the trail in total confidence. A roomy reach measurement, slack head angle, proportional seatstay measurements, and a steep, 77-degree effective seat tube work in sync to create a balanced and precise bike. JEFFSY keeps you, the rider, as the focus – It’s your best friend, after all.

FLIP CHIP

FLIP CHIP

Situated at the lower shock mount, the Flip Chip makes it quick and easy to adjust the geometry according to your ride style. This chip is set to low by default but increases the BB height by 8mm and ST/HT angle by 0.6 degrees in the high position. It's your call: Choose high for enhanced agility, precision, and climbing efficiency or low for trail-ripping confidence and a lower center of gravity.

Virtual Four Link

Virtual Four Link

Our V4L suspension technology is award-winning and has seen more than a few podiums in its time. Sensitive off the top, the design provides claw-like traction on loose terrain while remaining supportive through the mid-stroke. The end-stroke ramps up to prevent bottom-out, even on monster jumps, and did we mention the pop? Load up that linkage and let it fly.

SIZE-SPECIFIC REAR ENDS

SIZE-SPECIFIC REAR ENDS

Proportional seatstay lengths ensure JEFFSY is perfectly balanced. By keeping the front and rear center in check, the ride character is fast, confident, and predictable, for total control when things get hectic.

THREE FRAMES TO CHOOSE

THREE FRAMES TO CHOOSE

Depending on your weapon of choice, your JEFFSY will feature either a carbon or hand-crafted aluminum frameset. Our carbon fiber frames come in two options: High Modulus and Ultra Modulus. Both materials are equally durable and built for rowdy riding, with Ultra Modulus being the lighter choice.

FRAME PROTECTION

FRAME PROTECTION

Extensive chainstay and seatstay protection guards the frame from chain slap, while the knobs reduce chain slap noise. All you’ll hear is the adrenaline rushing through your veins and your tires rolling over the trail.

SEALED BEARINGS

SEALED BEARINGS

In addition to the double-sealed industrial bearings used, all pivot points are equipped with an additional seal to keep water and dirt at bay, protecting the bearings and extending their service life.

HEEL CLEARANCE

HEEL CLEARANCE

Increased heel clearance to reduce friction caused by the shoes rubbing on the frame while riding.

DOWNTUBE PROTECTION

DOWNTUBE PROTECTION

Silence is the sound of speed. More than just robust protection, the extensive frame guards eliminate unwanted noise, keeping you focused on the trail ahead as you descend like a ninja. JEFFSY even goes a step further: Beneath the bolt-on downtube protector lies sound-deadening foam to keep you cruising through those "Oh sh*t" moments without fear.

S
153 cm - 166 cm | 5'0" - 5'5"
M
162 cm - 176 cm | 5'4" - 5'9"
L
172 cm - 185 cm | 5'8" - 6'1"
XL
181 cm - 194 cm | 5'11" - 6'4"
XXL
190 cm - 203 cm | 6'3" - 6'8"

Toptube
Reach
Stack
Seattube
Chainstay
Headtube Angle
Seattube Angle (eff)
BB Drop low/<br>high
wheelbase
headtube
BB Height
Standover height
Toptube
Reach
Stack
Seattube
Chainstay
Headtube Angle
Seattube Angle (eff)
BB Drop low/<br>high
wheelbase
headtube
BB Height
Standover height

Flip Chip Position

low

high

s

m

l

xl

xxl

Toptube
578 mm
593 mm
609 mm
627 mm
645 mm
Reach
435 mm
455 mm
475 mm
495 mm
515 mm
Stack
613 mm
620 mm
627 mm
634 mm
642 mm
Seattube
385 mm
410 mm
435 mm
460 mm
485 mm
Chainstay
437 mm
437 mm
437 mm
442 mm
442 mm
Headtube Angle
65°
65°
65°
65°
65°
Seattube Angle (eff)
76,9°
77,5°
77,9°
78,3°
78,6°
BB Drop low/
high
33 mm
33 mm
33 mm
33 mm
33 mm
wheelbase
1191 mm
1214 mm
1238 mm
1266 mm
1289 mm
headtube
100 mm
108 mm
116 mm
124 mm
132 mm
BB Height
343 mm
343 mm
343 mm
343 mm
343 mm
Standover height
730 mm
728 mm
732 mm
738 mm
742 mm
Toptube
562 mm
585 mm
607 mm
630 mm
652 mm
1
Reach
442 mm
462 mm
481 mm
501 mm
521 mm
1
Stack
608 mm
615 mm
622 mm
629 mm
636 mm
1
Seattube
385 mm
410 mm
435 mm
460 mm
485 mm
1
Chainstay
435 mm
435 mm
435 mm
440 mm
440 mm
1
Headtube Angle
65,6°
65,6°
65,6°
65,6°
65,6°
1
Seattube Angle (eff)
77,5°
78,1°
78,5°
78,9°
79,2°
1
BB Drop low/
high
25 mm
25 mm
25 mm
25 mm
25 mm
1
wheelbase
1189 mm
1213 mm
1236 mm
1265 mm
1288 mm
1
headtube
100 mm
108 mm
116 mm
124 mm
132 mm
1
BB Height
351 mm
351 mm
351 mm
351 mm
351 mm
1
Standover height
738 mm
736 mm
740 mm
746 mm
750 mm
1

Flip Chip Position

low

high

 

s

m

l

xl

xxl

Toptube
578 mm
593 mm
609 mm
627 mm
645 mm
Reach
435 mm
455 mm
475 mm
495 mm
515 mm
Stack
613 mm
620 mm
627 mm
634 mm
642 mm
Seattube
385 mm
410 mm
435 mm
460 mm
485 mm
Chainstay
437 mm
437 mm
437 mm
442 mm
442 mm
Headtube Angle
65°
65°
65°
65°
65°
Seattube Angle (eff)
76,9°
77,5°
77,9°
78,3°
78,6°
BB Drop low/
high
33 mm
33 mm
33 mm
33 mm
33 mm
wheelbase
1191 mm
1214 mm
1238 mm
1266 mm
1289 mm
headtube
100 mm
108 mm
116 mm
124 mm
132 mm
BB Height
343 mm
343 mm
343 mm
343 mm
343 mm
Standover height
730 mm
728 mm
732 mm
738 mm
742 mm
Toptube
562 mm
585 mm
607 mm
630 mm
652 mm
Reach
442 mm
462 mm
481 mm
501 mm
521 mm
Stack
608 mm
615 mm
622 mm
629 mm
636 mm
Seattube
385 mm
410 mm
435 mm
460 mm
485 mm
Chainstay
435 mm
435 mm
435 mm
440 mm
440 mm
Headtube Angle
65,6°
65,6°
65,6°
65,6°
65,6°
Seattube Angle (eff)
77,5°
78,1°
78,5°
78,9°
79,2°
BB Drop low/
high
25 mm
25 mm
25 mm
25 mm
25 mm
wheelbase
1189 mm
1213 mm
1236 mm
1265 mm
1288 mm
headtube
100 mm
108 mm
116 mm
124 mm
132 mm
BB Height
351 mm
351 mm
351 mm
351 mm
351 mm
Standover height
738 mm
736 mm
740 mm
746 mm
750 mm
Jeffsy 29 Core Range Manual - MY2024

Jeffsy 29 Core Range Manual - MY2024

PDF | 7.88 MB

Insights

50%
Downhill
50%
Uphill

The Power Of Friendship

Now in its third iteration, JEFFSY rewrites the rulebook for trail bike performance. No half measures; only Trail Excellence.

Choose Your Jeffsy

CORE 5

29

6499
Frame Carbon 150mm/145mm
Fork FOX 36 FLOAT FACTORY
Shock FOX FLOAT X FACTORY
Drivetrain SRAM X0 EAGLE TRANSMISSION
Go to bike

CORE 4

29

5499
Frame Carbon 150mm/145mm
Fork ROCKSHOX LYRIK ULTIMATE
Shock ROCKSHOX SDLX ULTIMATE
Drivetrain SRAM GX EAGLE TRANSMISSION
Go to bike

CORE 3

29

3099
4299
Frame Carbon 150mm/145mm
Fork FOX 36 FLOAT PERFORMANCE
Shock FOX FLOAT X PERFORMANCE
Drivetrain SRAM GX EAGLE
Go to bike

CORE 2

29

3299
Frame Alloy 150mm/145mm
Fork FOX 36 FLOAT PERFORMANCE
Shock FOX FLOAT X PERFORMANCE
Drivetrain SRAM GX EAGLE
Go to bike

CORE 1

29

1999
2799
Frame Alloy 150mm/145mm
Fork ROCKSHOX LYRIK BASE
Shock ROCKSHOX DLX SELECT+
Drivetrain SRAM NX EAGLE
Go to bike
Uncaged

UNCAGED 13

MX

2499
3499
Frame Alloy 150mm/145mm
Fork MARZOCCHI BOMBER Z1
Shock MARZOCCHI BOMBER AIR
Drivetrain SRAM GX EAGLE
Go to bike
Uncaged

UNCAGED 14

29

4999
Frame Carbon 150mm/145mm
Fork ÖHLINS RXF36 M.2 AIR
Shock ÖHLINS TTX2 AIR
Drivetrain SHIMANO XT RD-M8100
Go to bike
Alternatives

YT
Range

Trail
All Mountain
Enduro
YOU ARE LOOKING FOR AN ALTERNATIVE?

Not sure if this is the perfect fit? Go ahead and browse more models!