The YT JEFFSY 29 AL Comp is the defending champion in this group test, securing both the coveted Best in Test and Best Value titles last year. For the new season, YT kept revisions down to a minimum and just switched out the drivetrain, so is that enough to defend the title?

For an overview of the test fleet head to the group test: Good times guaranteed! 7 trail bikes under € 3,000 in Review

YT JEFFSY 29 AL Comp review
YT JEFFSY 29 AL Comp | 140/140 mm (front/rear) | 13.39 kg | € 2,799

Upgrade or downgrade? Considering YT’s new choice in drivetrain, we reckon this question might be on many people’s lips. It consists of a mix of Shimano and E*Thirteen components, and in fact, at 511%, this drivetrain setup offers an even larger gear range than an SRAM GX Eagle. According to YT, it is also more robust, easier to adjust and more reliable. And indeed: In practice, this melange demonstrated precise, crisp shifting. It was only marginally let down by the budget SLX gear lever. The rest of the componentry is absolutely spot on. Although the E*thirteen dropper seat post only offers three fixed positions, we were very pleased with the super ergonomic lever. The 140 mm travel RockShox PIKE RC is beyond reproach, and the SRAM Guide RS brakes convinced the test riders with good ergonomics and modulation.

The YT JEFFSY 29 AL Comp is the defending champion in this group test
Helmet Troy Lee A1 | Brille Oakley Radar | Shirt ION Tee LS Scrub Amp | Shorts ION Bikeshorts Scrub Amp

The motto at YT is “Good Times” – and the bike conveys that from the first few metres aboard. The sitting position is very comfortable, and if you move the saddle forward a little, you don’t feel like you’re pedalling from too far over the rear wheel, even on steep climbs. Even when left fully open, the suspension hardly bobs, so the JEFFSY makes for a very capable climber. However, the grippy MAXXIS tyres are quite slow rolling, and it’s certainly not the fastest going uphill. As compensation, however, you’ll be rewarded with an extra dose of fun on the way back down.

  No more excuses with the YT JEFFSY 29 AL!No Excuses!

The bike couldn’t be more balanced! The rear end is very progressive and firm–typical YT– so the bike constantly invites you to play with the terrain and jump off and over things. With lots of fast, hard hits, however, the ride feels a little harsh, and you get the impression that they sacrificed some of the bike’s descending potential away by making the rear end a little too progressive. Thanks to the low bottom bracket (32 mm BB drop) you’re really integrated between the large wheels. Despite not having a super long front triangle or ultra-slack head angle, the bike rides through demanding terrain with buckets of confidence. At the same time, the JEFFSY was the most agile 29er in the test and proves that large wheels are anything but cumbersome.

YT JEFFSY 29 AL Comp in detail

Fork RockShox Pike RC 140 mm
Rear shock RockShox Monarch RT 140 mm
Brakes SRAM Guide RS 200/180 mm
Drivetrain Shimano SLX / E+Thirteen TRS+
Seatpost E+Thirteen TRS+ 150 mm
Stem Race Face Turbine R 50 mm
Handlebar Race Face Turbine R 780 mm
Tires Maxxis Minion DHR II
Wheels DT Swiss M1900 Spline
Weight 13.57 kg
Price € 2,799

YT uses a Shimano drivetrain with an E*thirteen cassette. This offers a 511% gear range. The drivetrain is supposed to be more robust and reliable than an Eagle. We certainly had no problems with it in the test.
Make it steeper
Unfortunately, the seat tube angle of the JEFFSY is still too slack. You’ll have to shift the saddle forward to get the most comfortable position.
The JEFFSY will only take YT’s own water bottle – not ideal, but better than nothing
The lever of the E*thirteen dropper seat post is one of the best on the market
The cables routed on the outside make maintenance much easier, and they don’t rattle at all. Aesthetically, however, we’ve seen neater solutions.

Geometry of the YT JEFFSY 29 AL Comp

Size S M L XL
Top tube 571 mm 592 mm 616 mm 637 mm
Head tube 90 mm 95 mm 110 mm 115 mm
Head angle 67/67.5° 67/67.5° 67/67.5° 67/67.5°
Seat angle 74,5/75° 74,5/75° 74,5/75° 74,5/75°
Chainstay 435 mm 435 mm 440 mm 440 mm
BB Drop 32/24 mm 32/24 mm 32/24 mm 32/24 mm
Wheelbase 1132 mm 1154 mm 1178 mm 1205 mm
Reach 405 mm 425 mm 445 mm 465 mm
Stack 605 mm 610 mm 623 mm 628 mm
The YT JEFFSY is a brilliant bike to have fun on!

  Upgrade tip: XT gear lever – doesn’t improve the riding, but it feels way better!


The YT JEFFSY is a brilliant bike to have fun on! It excels on flowing trails as well as rough descents. It climbs well, although you won’t set a PB. The componentry is well thought-out, especially for the price! Our Best Value tip!


+ well-considered spec with amazing value for money
+ potent, balanced geometry with a lot of composure
+ fun machine


– slow climber
– seat tube is a little too long


For more information head to:

The test fleet

For an overview of the test fleet head to the group test: Good times guaranteed! 7 trail bikes under € 3,000 in Review

All bikes in test: Canyon Spectral CF 8.0 | Ghost SLAMR X 5.9 AL | Giant Trance 1.5 LTD | ROSE ROOT MILLER 2 | Trek Fuel EX 8 29 XT | Whyte T-130 S

This article is from ENDURO issue #033

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