YT’s award-winning Jeffsy gets an overhaul for 2019

Longer, lower, slacker, steeper, taughter - all in the right places.

YT has launched an updated version of its Jeffsy trail bike, with 29” and 27.5” wheeled carbon bikes ready to buy, right now!

The YT Jeffsy CF Pro Race
The YT Jeffsy CF Pro Race

The 2018 YT Jeffsy CF 29 was our Trail Bike of the Year - not an accolade that comes without competition, it beat over 20 similarly priced and specc’d bikes in the process. That generation Jeffsy, technically, wasn’t the best bike in the test. However, the test team, myself included, simply found it the most fun bike on test - and if a trail bike has to be anything, it’s fun.

It's definitely a fast bike, and super capable on a wide range of terrain
It's definitely a fast bike, and super capable on a wide range of terrain

Criticisms were fair though - the frame wasn’t ‘up to date’, the geometry was relatively conservative, and its climbing performance was unlikely to put many KOMs under stress. The latest iteration of the Jeffsy has tackled these ‘issues’, and you can find my first impressions of how the bike rode in my YT Jeffsy First Ride.

2019 YT Jeffsy Key Features

  • 29” (140mm) and 27.5” (150mm) versions
  • ‘Pro Race’ models get extra 10mm travel front and rear thanks to longer stroke forks and shocks
  • Currently carbon frame only
  • Significant increases in reach figures
  • Slacker head and steeper seat angles
  • Increased anti-squat
  • Stiffer head tube area

Updates to the 2019 YT Jeffsy

I rode the new Jeffsy in Portugal to get a taste of the new bike
I rode the new Jeffsy in Portugal to get a taste of the new bike

YT has released the new Jeffsy with both 29" and 27/5" wheels, though it feels that the 29er has had the most attention from the team, and this mirrors our experience and attitudes towards trail bikes - 29ers, on the whole, make a lot of sense on the trail. It is also the version of the Jeffsy that has a more radically different shape to the previous generation.

The headline figures for the bikes’ geometries show that YT doesn’t want to be left behind, geometrically. The reach in a size large grows from 445mm to 470mm, with the seat tube sat at 77 degrees (formerly 74.5 degrees). Head angles drop from 67 to 66 degrees, while the seat tube shortens by 45mm to 435mm - giving much more room for longer droppers, or smaller riders to ‘size up’ their bike. YT will also now offer the Jeffsy in five sizes - Small to XXL.

The headtube area has been beefed up
The headtube area has been beefed up

The 27.5” bike has a 460mm reach, 65.5 degree head angle and 76 degree seat angle.

The geometries above are for when the Jeffsy is in its ‘super low’ position - you could, in theory, use the flip-chip to raise and steepen the bike a touch, though we can’t think of many situations where we’d bother.

You can change the geometry a little with this flip-chip, though it's arguable as to how necessary that would be
You can change the geometry a little with this flip-chip, though it's arguable as to how necessary that would be

Both wheel sizes get three carbon models, and an alloy model remains from the previous generation of the frame.

29” bikes get 140mm of travel front and rear, and the 27.5” bikes are 150mm. YT now uses Metric length shocks in their bikes. The top-end Pro Race Jeffsy gets a longer stroke shock, and longer forks, however, boosting them to 150mm (29”) and 160mm travel (27.5”).

YT also claims that they have increased the anti-squat figures for the Jeffsy by around 30% through the suspension’s stroke. This gives the bike a much more pedal-friendly nature, both on climbs and on pedally sections of trail, in theory.

Another new feature of the Jeffsy comes from their Tues DH bike. YT’s mechanics wanted a set of pivot bolts that could all be accessed from one side of a bike’s work-stand, to save continually moving around the bike during strip-downs. YT designed their pivots (save for the drive-side horst-link pivot) to all be strippable from the non-drive side, and this can now be found on the Jeffsy.

All the pivots can be serviced from one side of the bike (except the drive-side horst-link pivot)
All the pivots can be serviced from one side of the bike (except the drive-side horst-link pivot)

It’s only a small feature, that many may not appreciate, but it keeps the driveside looking smooth, and will make maintenance easier. Speaking of which, YT has also apparently improved sealing for the bearings, and are using radial bearings from Acros in the Jeffsy.

This ‘liveability’ has also taken the form of increased, and smoother mud clearance for the back-end, with more room and less ‘shelves’ for mud to collect on - ideal for us in the UK, at the very least!

YT says that there's less places for mud to collect
YT says that there's less places for mud to collect

There is a glass-fibre downtube protector present, and YT bolts it on, as they found glue doesn’t work so well in wetter conditions. There’s also a PU material protector on the seatstay, which merges seamlessly around the mech hanger - this is said to prevent the chain rubbing on any carbon and should keep the bike quieter.

Cables are routed internally along internal tubing, and they’re only clamped in place at one place on the frame. Finally, there’s room for a specific 600ml YT designed bottle in all frame sizes, using the Fidlock system. This bottle will be available aftermarket, also.

YT only clamp the cable outers in one place - just here!
YT only clamp the cable outers in one place - just here!

Want to see a wild, new DH bike from Starling?

2019 YT Jeffsy models

Jeffsy 27 CF Pro Race and Jeffsy 29 CF Pro Race

Top-level YT Jeffsy CF Pro Race comes with all the kit!
Top-level YT Jeffsy CF Pro Race comes with all the kit!
  • Fork: Fox 36 Factory
  • Shock: Fox Float DPX2 Factory
  • Drivetrain: Shimano XTR with e13 TRS Plus 9-46 cassette and  TRS Race cranks
  • Wheels/Tyres: e13 TRS Race Carbon / e13 TRS Race/TRS Plus 2.35”
  • Brakes: SRAM Guide RSC
  • Finishing: Renthal cockpit, Fox Transfer post, e13 TRS Race chainguard
  • £4799 / $5699 / €5299

Jeffsy 27 CF Pro and Jeffsy 29 CF Pro

The CF Pro is a very tidy package for the money
The CF Pro is a very tidy package for the money
  • Fork: RockShox Pike RCT3
  • Shock: RockShox Deluxe RT3
  • Drivetrain: SRAM GX Eagle
  • Wheels/Tyres: e13 TRS Plus / e13 TRS Plus 2.35”
  • Brakes: SRAM Guide RS
  • Finishing: RaceFace Turbine R35 cockpit, e13 TRS Plus post, SDG Fly MTN saddle
  • £3499 / $4299 / €3899

Jeffsy 27 CF Comp and Jeffsy 29 CF Comp

The Jeffsy CF Comp is the cheapest carbon model
The Jeffsy CF Comp is the cheapest carbon model
  • Fork: Fox 34 Performance Elite
  • Shock: Fox Float DPS Performance Elite
  • Drivetrain: Shimano XT with e13 TRS Plus 9-46 cassette and  TRS cranks
  • Wheels/Tyres: e13 TRS / e13 TRS Plus 2.35”
  • Brakes: SRAM Guide R
  • Finishing: Renthal cockpit, e13 TRS Plus post, SDG Fly MTN saddle
  • £2999 / $3499 / €3299

Jeffsy 27 AL Base and Jeffsy 29 AL Base

The AL Base is the entry level Jeffsy, and is a hangover platform from the previous generation
The AL Base is the entry level Jeffsy, and is a hangover platform from the previous generation
  • Fork: Fox 34 Rhythm
  • Shock: Fox Float DPS Performance
  • Drivetrain: SRAM NX Eagle
  • Wheels/Tyres: DT Swiss M1900 Spline / Maxxis Minion DHR II 2.4”
  • Brakes: SRAM Guide T
  • Finishing: RaceFace Aeffect R cockpit, SDG Tellis post, SDG Fly MTN saddle
  • £2099 / $2299 / €2299
Tom Marvin

Technical Editor, Tech Hub, UK
Tom's been riding for 15 years, and has always chopped and changed bikes as soon as his budget allowed. He's most at home in the big mountains, having spent nigh on 30 weeks riding the Alps, as well as having lived a stone's throw from the Scottish Highlands for four years. Tom also enjoys racing events like the Strathpuffer and the Trans Nepal.
  • Discipline: Mountain
  • Preferred Terrain: Steep and super tech or fast and flowy
  • Current Bikes: Canyon Spectral, Pivot Mach 429SL, Mondraker Vantage R +
  • Dream Bike: Transition Scout
  • Beer of Choice: Gin & tonic
  • Location: Bristol, UK

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