YT JEFFSY Pro 29 on test

The YT JEFFSY Pro 29 has been given a significant performance boost for the new season. YT have introduced the extra centimetre of travel, previously reserved for the flagship CF Pro Race model, across the range. We were very excited to see how this would make the bike fare against the competition.

Click here for an overview of the best trail bike in test.

The YT JEFFSY 29 looks like a bike that will happily tackle whatever you throw at it, and that’s before you even take a seat on it. The low slung carbon frame with its beefy head tube instils you with confidence the moment you see it. Of course, we would have preferred the CF Pro Race model, but unfortunately, it wasn’t available at the time of our test. Nonetheless, the JEFFSY Pro, priced at € 3,899, also has a very well considered spec. The 150 mm travel RockShox PIKE Select+ up front combined with a Super Deluxe Select+ at the rear are a proven combination. The SRAM G2 RSC brakes offer sufficient braking power for most trails, but heavy riders or those who use the JEFFSY for shuttling would be better off with CODE brakes. YT’s 150 mm Postman dropper performs smoothly but with the seat tube as short as it is, there would have been enough room for 170 mm version. We’re happy to see that in 2020 YT are speccing MAXXIS tires for the JEFFSY, fitting a Minion DHR II on the front and rear. The JEFFSY is available with 27.5” wheels or the 29ers we had on our test bike, comes in five sizes from S–XXL and in two different colourways.

YT JEFFSY CF PRO

€ 3,899

Specifications

Fork RockShox Pike Select+
Rear Shock RockShox Super Deluxe Select+
Seatpost YT Postman 150 mm
Brakes SRAM G2 RSC 200/180 mm
Drivetrain SRAM GX Eagle 32/10-50
Stem E13 Plus 50
Handlebar E13 Plus 780 mm
Wheelset E13 TRS Plus
Tires MAXXIS MINION DHR II EXO 2,4

Technical Data

Size S M L XL XXL
Weight 13,78 kg
Wheelsize 29"
Travel (f/r) 150/150 mm

**Unnecessary**
We never put the flip chip in the high setting. The JEFFSY climbs well enough in the low setting and is lots of fun on every trail.

**Annoying**
YT have revised the rubber plugs for the cable ports, but they kept coming loose on our test bike

**Lacking support**
The RockShox Super Deluxe Select+ lacks mid-stroke support on the YT. Since there is no way of adjusting the damping externally, we’d advise active riders to install additional volume spacers in the shock.

**Very quiet**
The YT JEFFSY makes a very high-quality impression overall. This is underlined by the lack of background noise – there’s no rattling to be heard here.

**Lots of space on the dance floor**
Thanks to the low-slung top tube, you’ve got lots of space. This instils you with confidence in steep terrain and motivates you to ride the bike very actively. We would just have liked an even longer dropper post.

**Custom**
Thanks to its width, the stubby, custom made Fidlock bottle can hold up to 600 ml.

Geometry of the YT JEFFSY Pro 29

Due to the short seat tube and the gradual increments in reach across the range of available sizes, you’ll usually be able to choose between two sizes. At 180 cm tall, our test riders opted for a size L, which fit perfectly. The reach is 470 mm, the head angle is a decent 66° and the seat tube angle is very steep at 77°. On sizes XL and XXL, the chainstay length increases from 435 mm across the other sizes to 440 mm. A flip chip allows you to adjust the angles by 0.5° though we kept the JEFFSY in the slack setting.

As befits a good trail bike, the JEFFSY climbs well too!

Size	S	M	L	XL	XXL
Seat tube	400 mm	415 mm	435 mm	460 mm	485 mm
Top tube	571 mm	592 mm	614 mm	637 mm	659 mm
Head tube	100 mm	105 mm	110 mm	120 mm	125 mm
Head angle	66,5°/67°	66,5°/67°	66,5°/67°	66,5°/67°	66,5°/67°
Seat angle	77,5°/78°	77,5°/78°	77,5°/78°	77,5°/78°	77,5°/78°
Chainstays	435 mm	435 mm	435 mm	440 mm	440 mm
Wheelbase	1,171 mm	1,193 mm	1,215 mm	1,244 mm	1,266 mm
Reach	434 mm	454 mm	474 mm	494 mm	514 mm
Stack	615 mm	620 mm	624 mm	633 mm	638 mm

In the past, YT’s weren’t known for their pedalling efficiency on the climbs, but all that is set to change with the new JEFFSY. The pedalling position on the bike is super central, meaning that no matter how steep the climbs, you never feel too far back and can always keep the front wheel under control in technical sections. The suspension performs efficiently and we never felt the need to reach for the climb switch. We would have preferred a 30 t chainring up front and while lighter wheels would make the bike a little more spritely, the fitted ones are okay considering the price.

Stay off the brakes! The YT JEFFSY is happy at speed and doesn’t have to shy away from shuttle days either.

On the descents, the handling of the JEFFSY is extremely forgiving. The weight distribution on the bike is spot on, making it extremely balanced and intuitive through corners. Thanks to the bike’s roomy cockpit and massive standover clearance, you have a lot of freedom of movement, with the JEFFSY inviting you to drift around corners and ride the bike as loose as possible. The rear suspension performs sensitively and absorbs bumps with ease, but it lacks mid-stroke support when ridden actively or popping off obstacles. We’d advise installing a few volume spacers to compensate – even with them fitted, we were still able to make use of all the available travel.

Tuning tip: volume spacers in the shock | possibly smaller chainring | lighter wheels if desired | more powerful brakes if necessary

**Helmet** Giro Montaro | **Glasses** Smith Flywheel | **Jersey** Fox Ranger | **Short** Fox Ranger | **Kneepads** Fox Launch Pro | **Shoes** ION Rascal Select

How does the YT JEFFSY CF Pro compare to the competition?

The YT JEFFSY and the Nukeproof Reactor appeal to a very similar target group. Neither of them shows any climbing weaknesses worth mentioning, with the YT offering a little more traction and comfort. On the descents, the Nukeproof rides like it’s on rails, whereas the JEFFSY invites you to let the rear end break out and slide. With its increased mid-stroke support, the Nukeproof is a better choice on shaped flow trails.

Riding Characteristics

Uphill

sluggish
efficient

Agility

cumbersome
playful

Stability

nervous
confident

Handling

demanding
balanced

Suspension

harsh
plush

Fun Factor

planted
poppy

Value for money

terrible
very good

Intended Use

XC

Trail

Enduro

Downhill

Conclusion of the YT JEFFSY Pro 29

The YT JEFFSY Pro 29 is quite rightly one of the most popular trail bikes on the market, offering capable handling on the descents as well as excellent climbing prowess. It’s an excellent package, rounded off by carefully chosen componentry, at a fair price. Our only criticism is the lack of support from the rear suspension.

Tops

balanced, confidence instilling and fun geometry
great value for money
excellent climber

Flops

rear suspension bobs when pedalling out of the saddle
weak brakes
cable port plugs kept coming loose

For more information head to yt-industries.com

The test field

Click here for an overview of the best trail bike in test.

This scale indicates how efficiently the bike climbs. It refers to both simple and technical climbs. Along with the suspension, the riding position and the weight of the bike all play a crucial role.↩
How does the bike ride and descend? How spritely is the bike, how agile is it through corners, how much fun is it in tight sections and how quickly can it change direction?↩
Is the bike stable at high speeds? Is it easy to stay in control in demanding terrain? How composed is it on rough trails? Stability is a combination of balanced geometry, good suspension and the right spec.↩
This is all about how balanced the bike is and particularly about how well it corners. Balanced bikes require little physical effort from the rider and are very predictable. If a bike is unbalanced, the rider has to work hard to weight the front wheel to generate enough grip. However, experienced riders can have a lot of fun even with unbalanced bikes.↩
How sensitive is the suspension over small bumps? Can it absorb hard impacts and does it soak up repeated hits? Plush suspension not only provides comfort and makes a bike more capable, but it also generates traction. The rating includes the fork and the rear suspension.↩
This aspect mainly comes down to the suspension. How much pop does it have, does it suck up the rider’s input or is it supportive, and how agile and direct is the bike?↩
We don’t calculate value for money in an excel spreadsheet or based on how high-end a bike is specced. We are more concerned with how a bike performs on the trail and how the bike benefits the rider. What good are the best components if the bike doesn’t perform well on the trail? Expensive bikes with a lower-end spec can offer very good value for money – provided they excel where it matters. Just as supposedly cheap bikes with good components can get a bad rating if they don’t deliver on the trail.↩
No, it’s not about racing, it’s about efficiency. Fast, fleet-footed and efficient – those who want to speed along flowy singletrack and gravel roads need a defined and spritely bike that accelerates with ease and efficiency. Nevertheless, reliable components are important too. We interpret XC more like the Americans do: big back-country rides instead of a marathon or XC World Cup with the ultimate in lightweight construction! Uphill-downhill ratio: 80:30 (not everything has to be 100%!)↩
...also known as mountain biking. Classic singletrack with roots, rocks and ledges – sometimes flowy, sometimes rough. For this, you need a bike with good all-round qualities, whether climbing or descending. Uphill-downhill ratio: 50:50↩
Even more extreme and challenging compared to Trail riding, riddled with every kind of obstacle: jumps, gaps, nasty rock gardens, ruts and roots. For this, you need (race)proven equipment that forgives mistakes and wouldn’t look out of place on a stage of the Enduro World Series. Climbing is just a means to an end. Uphill-downhill ratio: 30:70↩
Strictly speaking, a 200 mm travel downhill bike is the best choice for merciless tracks with big jumps, drops and the roughest terrain. Those would be the black or double-black-diamond tracks in a bike park. But as some of the EWS pros (including Sam Hill) have proven, it’s the riding skills and not the bike that define what you can ride with it. Climbing? On foot or with a shuttle, please! Uphill-downhill ratio: 10:90↩
You can find more info about our rating system in this article: Click here! ↩

Did you enjoy this article? If so, we would be stoked if you decide to support us with a monthly contribution. By becoming a supporter of ENDURO, you will help secure a sustainable future for high-quality mountain bike journalism. Click here to learn more.

Words: Photos: Christoph Bayer, Finlay Anderson, Markus Frühmann, Jonas Müssig

YT JEFFSY Pro 29 on test – a capable trail bike for those who like it rough!

YT JEFFSY CF PRO

Specifications

Technical Data

Geometry of the YT JEFFSY Pro 29