Review | YT Jeffsy | Dirt Mountain Bike

Mountain Biking Magazine


Trail and Enduro Bikes


YT Industries unleash Jeffsy

After such a sumptuous marketing campaign YT really had to deliver on their new trail bike. And the result? One thing is for sure, they’ve made a lightning fast bike here.


The YT Jeffsy Review

Welcome to the YT Jeffsy review! We’re excited today to be examining the potential of this beaut, so let’s get right to it.

Shape and Purpose

With 140mm travel front and rear, the Jeffsy sits bang in the middle of trail bike territory and its sub-27lb weight certainly makes sure of that. We believe there’s very little point in making a trail bike with this amount of travel or under with anything other than 29” wheels. It appears many brands are now thinking this way and slowly riders are seeing the advantages particularly all-round Uk conditions where the bigger wheels offer more grip particularly in wetter conditions.

“We now attack the all-mountain sector. And shake up every prejudice about it”

YT have taken their time to get the numbers correct on this bike, this is because they understand there have been great 29ers around for many years. YT aren’t one of what seems to be a band of brands who have recently been shouting that they are the first to offer aggro 29 geometry. Pitching it at 140mm is the correct decision – not too much, not too little, lightweight, inexpensive, fully loaded and ….flat out. They’ve got it fully bang on in pretty much every numeric measurement. And the ride? Read on.


Four sizes, six specifications ranging from €2199 to €4499 in carbon and aluminium YT realise that it’s the kind of bike most people ride. The Jeffsy has a high and low geometry setting and the bottom bracket in the latter sits at a 32mm drop, which is just about perfect, just one element of the numbers that allow the bike to be a nimble one.


There’s a good spread on sizing and in terms of reach our XL bike is pretty close to a similar size Specialized Stumpjumper, what could be considered a close comparison bike. Let’s take a look at some key numbers here:

Jeffsy CF Pro Size XL

Head angle:     66.8/67.6

Wheelbase:     1206mm

Chainstay:       440mm

Fork Offset:     46mm

Bottom bracket drop: 32/24mm

Chassis/Suspension. YT have opted for Fox to support their top end bikes this season and in the Fox 34 Float and excellent choice. Rearwards the linkage driven Fox Float DPS Factory has a point four spacer fitted and the lockout offers an incredibly firm platform off which to drive upwards on climbs. Many will already be thinking Fox 36 up front in 150mm travel, well we certainly were.


The Jeffsy’s frame is full carbon with plenty of armouring, great detailing in terms of cable routing and smooth unobtrusive lines both visually and on the hoof. At 148mm boost rear we had no doubt of the bikes stability even before taking to the hill. What we were surprised at was the quite subtle frame naming. We like this a lot. The bike is super stealth but it comes in such a range of colours from red’s and blue’s to black and white to all- black they have everyone covered. RAWR/Jet black is the one though right?

Componentry. There’s so much ‘de luxe’ involved here that there’s almost nothing to discuss here as its quality top to bottom and back to front. Sram X01, Sram Guide Ultimate, Race Face carbon crank, Renthal Apex stem and Fatbar carbon handlebar, DT Swiss XMC 1200 spline…these are all highly regarded products that offer performance, reliability and weight advantages. It even comes ready with big wide Onza 2.4 tyres to add a touch more comfort to the ride.


The big news with the Jeffsy is its place in part of a range of six component packages in both Sram and Shimano with even the lowest price offerings coming with such great parts as Sram Reverb Stealth and Shimano SLX. These boys are going in for the kill with this bike.

Feeling. There is no hesitation with this bike when it comes to speed, its incredibly direct, pacey and is pretty much unstoppable when it gets moving. In fact it’s a very demanding bike, one that craves to be driven harder and harder, searching limits, always on the alert for rider engagement, to be picked up, jumped. Is it highly strung? Absolutely.


And it’s a bike with so many guises, it can be climbed quickly, is silent on the march and in battle. YT have truly mastered the suspension tune of this bike too. Strong, supportive, lively, accurate. The overall chassis/wheel balance has slightly more give than its Capra stable mate and this means you’ll not be holding back quite so much in the bigger breakers.


Limitations. You’d have to be a pretty miserable bastard to find fault with this bike. Slightly suspect Onza tyres? Not enough sizes? Doh, call me miserable…

Verdict. Have YT succeeded in their mission? Let’s remind ourselves what they set out to achieve with the Jeffsy:

“Building a trail-rocket which is comfortable and smooth to ride on, lightweight, ready to shred and still has the looks to kill for.”

Well, with a great shock tune, super light weight, great chassis balance, accurate steering, killer componentry, good frame detailing, nice range of sizing and specifications it’s very, very good indeed.  How good? Put it this way, when it comes to picking trail bike of the year we’ve got a real feeling this one could be the real McCoy.

What are your thoughts on this Jeffsy review? Let us now what you think.




CF PRO: €4499

CF COMP 1 Sram: €3599

CF COMP 2 Shimano: € 3599

AL COMP 1 Sram: €2799

AL COMP 2 Shimano: €2799

AL: €2199

See also

2017 Trek Remedy 9.9 Race Shop Limited






Newsletter Terms & Conditions

Please enter your email so we can keep you updated with news, features and the latest offers. If you are not interested you can unsubscribe at any time. We will never sell your data and you'll only get messages from us and our partners whose products and services we think you'll enjoy.

Read our full Privacy Policy as well as Terms & Conditions.