It’s fair to say that YT took many people by surprise when it launched its Jeffsy 29er trail bike. For a brand best known for bikes on the hardcore end of the spectrum, the combination of big wheels and 140mm of travel was quite a departure from its norm.
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However, it was very well received, with a combination of well sorted suspension, amazing direct-sales led value for both alloy or carbon frames, and handling that balanced fun with flat-out speed.
Markets in the Far East tend to prefer a 650b wheel because the average height of riders is shorter
All that makes it even stranger that YT would go and make a 650b wheeled version of the bike, but that’s exactly what it's gone and done.
There will be six bikes in the range: two entry level aluminium framed options and the rest using a carbon fibre frame.
All have 150mm of travel front and rear, save for the top-end Jeffsy 27 CF Pro Race which has travel boosted to 160mm at either end via a longer fork and increased stroke shock.
YT took the time to incorporate the latest design features into the new bikes, so that means they all use metric sized shocks as well as Boost 148 rear hub spacing.
While the top-end models do use 1x drivetrains, all the bikes are compatible with doubles, which are marked out with 'Two' in their name.
While many riders are fully committed to single ring set ups, especially in the UK, YT still needs to make sure it has something to offer markets that demand a double set up and so aren't willing to create 1x specific frames, feeling the extra cost involved would outweigh any benefits.
The question that's probably on your mind right now is why YT would choose to invest such time and effort in creating a new bike when its existing Jeffsy 29 has done so well?
It’s pretty simple. Firstly, the bike caters to riders who simply don’t like 29er wheels, for whatever reason that might be.
Secondly, and most important to YT, is the fact that the rapidly growing markets in the Far East tend to prefer a 650b wheel because the average height of riders is shorter.
With a number of new distributors in Asia to help supply that market, it’s becoming a bigger consideration for the brand, as well as many other players in the bike industry.
Smaller wheels but more reach
The bike isn’t a case of simply slipping smaller wheels into the same frame however.
Using what YT learnt from creating the 29er bike allowed it to reduce overall frame weight because YT knew exactly where it could remove material but keep the same strength.
It’s possible to tweak both head and seat angle as well as bottom bracket height
The move to the larger eye-to-eye metric shocks also meant that it could make the bike’s rear suspension kinematic around 4-5% less progressive, as the new shocks have much greater control at the end of the stroke — especially the RockShox Deluxe fitted to many of the bikes.
YT has also taken the opportunity to create much neater cable routing on the aluminium frames, with very tidy and rattle free clamps.
As well as having 10mm more travel than the 29er version, the Jeffsy 27 range also has a much more stretched out geometry, with a reach of 460mm in a size large compared to 445mm for a similarly sized 29er.
The smaller wheel also allows a 5mm tighter chainstay length, with the small and medium frames having a 430mm long stay and the large and extra large being 435mm.
As the bike comes with a variable geometry flip chip in the chainstay, it’s possible to tweak both head and seat angle as well as bottom bracket height.
In the slackest and lowest position you get a head angle of 66 degrees, making it some 0.9 degrees slacker than the big-wheeled machine, while the seat angle remains a similarly steep 75.5 degrees in the steepest setting.
Model range, specs and pricing
Jeffsy 27 CF Pro Race
- £3,799 / €4,499 / $TBC / AU$TBC
- Carbon fibre frame, 160mm travel
- Fox Factory 34 and Float X suspension, Kashima coated
- SRAM X01 11spd drivetrain with Race Face Next SL cranks and E.13 TRS cassette
- E.13 TRSR SL carbon wheelset with E.13 TRSR and TSR rubber
- SRAM Guide Ultimate brakes, RockShox Reverb dropper post
- Weight: 12.4kg (measured, size XL)
Jeffsy 27 CF Pro
- £3,399 / €3,999 / $TBC / AU$TBC
- Carbon fibre frame, 150mm travel
- Fox Performance 34 fork and Float DPS shock
- SRAM X01 Eagle 12spd drivetrain
- E.13 TRS wheelset with Maxxis High Roller II rubber
- SRAM Guide RSC brakes with Race Face Turbine dropper post
- Coral red or jet black colour options
- Weight: 12.6kg (claimed)
Jeffsy 27 CF One
- £2,899 / €3,399 / $TBC / AU$TBC
- Carbon fibre frame, 150mm travel
- RockShox Pike RCT3 fork and Deluxe RT3 shock
- SRAM X1 11spd drivetrain with Race Face Turbine cranks
- E.13 TRS wheelset with Maxxis High Roller II rubber
- SRAM Guide RS brakes with Race Face Turbine dropper post
- Jet black and snow white colour options
- Weight: 13.2kg (measured, size large)
Jeffsy 27 CF Two
- £2,899 / €3,399 / $TBC / AU$TBC
- Carbon fibre frame, 150mm travel
- RockShox Pike RCT3 fork and Deluxe RT3 shock
- Shimano XT 2x11spd drivetrain with Race Face Turbine cranks
- E.13 TRS wheelset with Maxxis High Roller II rubber
- SRAM Guide RS brakes with RockShox Reverb dropper post
- Jet black and snow white colour options
- Weight: 13.3kg (claimed)
Jeffsy 27 AL One
- £2,199 / €2,599 / $TBC / AU$TBC
- Aluminium frame, 150mm travel
- RockShox Pike RC fork and Deluxe RT shock
- SRAM X1 11spd drivetrain with Race Face Turbine cranks
- DT Swiss M1900 Spline wheelset with Maxxis High Roller II rubber
- SRAM Guide RS brakes with E.13 dropper post
- Weight: 13.5kg (claimed)
Jeffsy 27 AL Two
- £1,799 / €2,099 / $TBC / AU$TBC
- Aluminium frame, 150mm travel
- RockShox Pike RC fork and Deluxe RT shock
- SRAM GX 2x11spd drivetrain with Race Face Aeffect cranks
- DT Swiss M1900 Spline wheelset with Maxxis High Roller II rubber
- SRAM Guide R brakes with RockShox Reverb dropper post
- Weight: 13.9kg (claimed)
Ride impressions
We managed to spend a few days aboard the new bikes on the rough and rocky trails around Malaga in Spain and will have a proper first ride of the bike soon, but our first impressions are that the new bike certainly shares much of its ride feel DNA with its bigger wheeled brother.
The suspension is as supple as ever, with good resistance to bottoming out despite offering plenty of grip in the initial part of the stroke.
The increased reach is very much welcome, allowing a much more confident ride feel and much more space to move about when climbing or descending.
Despite throwing it down some trails much better suited to downhill bikes rather than lightweight trail bikes, the bike was impressive. On some of the mega steep and loose trails, having a bit more off the head angle would have eased nerves, but we were definitely riding where YT's longer travel Capra would have been the natural choice.
On flatter trails, the bike is nice and lively without feeling uncontrolled. Though we didn't get to test it back-to-back with the 29er, despite having a longer reach, the Jeffsy 27 did feel a bit more perched, almost certainly a function of the big wheeler's much greater axle to bottom bracket drop.
It would have been very interesting to see if the big wheels could have coped with loose rocks more confidently too, though that's pure speculation.
We're looking forward to getting a bike for a proper long term test soon, though we will have a first ride of the Jeffsy 27 CF One very shortly.