YT Jeffsy Base 29 Review

Should I Buy This Bike?

Do you want a truly ripping trail bike, but don't want to go into debt to buy it? The YT Jeffsy Base 29 is an impressively capable, well-rounded, and high-performing bike at a very reasonable price. YT's direct to consumer sales model allows them to sell bikes with a price to component specification ratio that other brands simply can't touch. The Jeffsy's nicer components are just one reason this bike performs well above its price class; however, as the 2020 redesign has helped turn the shred-ability up even further. YT boosted the Jeffsy's travel by 10mm, up to 150mm front and rear for the 29-inch wheeled version (160mm for the 27.5-inch), and gave it a generous dose of the long and slack treatment. It's still a very well-rounded and versatile shred machine but is now far more stable and harder charging than the previous version. The geometry feels dialed, the suspension very well balanced front and rear, and our testers never found the Jeffsy's limits of speed or terrain. Climbing performance is quite good, although not its strongest suit due to its heavier weight. Despite that, this bike rivals the performance of bikes that cost double and is easily the best we've tested under $2500.

Fun Factor

The new Jeffsy Base 29 is an absolute blast to ride. The bike does it all and does most everything better than the competition in this price range. No matter the speed or terrain, the Jeffsy eats it up with responsive handling, a well-balanced suspension feel, and capabilities that you wouldn't expect from a bike this affordable. The component specification backs up the Jeffsy's performance and inspires the confidence to push this bike to its and your limits.

Feeling comfortable and confident in the bike you're riding can genuinely enhance your overall experience. Much like the previous Jeffsy, the 2020 version is easy to get along with and required only simple suspension adjustments to air pressures and rebound settings to dial it in. After about the second high-speed berm, it felt like we'd been riding this bike for years. The geometry is pretty much spot-on perfect by today's modern progressive standards and is the primary factor that this bike performs so well all-around. The added length to the wheelbase and reach have enhanced its stability along with the slacker 66-degree head tube angle(in the low setting) that feels confident and composed when you want to get rowdy. The longer slacker geometry isn't so extreme, however, and the Jeffsy remains maneuverable, predictable, and relatively playful. That versatility, along with a quality component spec makes it punch way above its weight class. You don't have to hold back in any way, and we think riding with unflinching confidence in your bike, especially a $2,300 bike, is a heck of a lot of fun.

Downhill Performance

The New Jeffsy Base absolutely slays the descents and easily outperformed every other bike in this price range. The 10mm of additional suspension travel, now 150mm front and rear, along with the updated longer and slacker geometry, has helped to create a bike that is composed and confidence-inspiring in any terrain. Point the Jeffsy down a steep, rocky chute or blast down a manicured flow trail, it eats it all up with an impressive combination of stability, maneuverability, and well-balanced suspension.

When YT redesigned the Jeffsy Base for 2020, they gave it 10mm more squish and did a great job bringing it in line with today's trail bike geometry trends. Cue the broken record, we feel like we write about longer and slacker pretty much every time we test a bike. There's a good reason for that, and the new Jeffsy fits the mold perfectly. The wheelbase has been extended to super stable 1225mm with the reach increasing to 468mm, opening up the cockpit a bit. While those numbers have increased, YT also managed to shorten the chainstays to 436mm. These shorter stays help to keep the Jeffsy a little poppy and playful, and it doesn't shy away from manuals or trailside hits. Despite the overall length of the Jeffsy, it remains plenty maneuverable in tight corners or low-speed tech. In the low geometry setting, the 66-degree head tube angle is appropriately slack, and this bike is ready, willing, and able to charge down whatever you are. Moving the flip-chips to the high setting steepens the head tube angle to 66.5-degrees and bumps the bottom bracket up 6mm for slightly crisper handling and pedal clearance. Testers found the high setting better for more technical XC style trail riding, while the low setting felt more planted and eager to charge the fall-line.

The addition of 10mm of front and rear travel bump the Jeffsy Base 29 up to 150mm (160mm for the 27.5-inch version) of trail-smoothing suspension. YT equipped it with a RockShox suspension package in the form of a Yari RC fork and a Deluxe Select rear shock. The Virtual 4 Link suspension design feels more linear than some, but it has good small bump compliance, a reasonably supportive mid-stroke, and is just progressive enough that bottom outs were pretty rare. We ran the rear shock at 30% sag, and it felt very well balanced with the front end. The Yari fork is a nice departure from the Recon forks found on many competitors in this price range. It has a sturdy chassis, wider stanchions, and an aggressive feel well suited to a bike that can charge this hard. Our test fork felt plush, and the Motion Control damper worked well. The cockpit is dialed with a 780mm handlebar and short, stout stem that provide plenty of leverage for muscling this bike around. The 150mm travel YT Postman dropper post ensures that your saddle is always in the perfect spot.

Uphill Performance

The Jeffsy Base 29 is a relatively good climber with a comfortable geometry and components that generally work well and enhance uphill performance. Our only real complaints about climbing on this bike were its heavier weight and the lack of a compression damping/climb switch on the rear shock. Otherwise, the seated position pedaling position is excellent, power transfer feels direct, and this bike handles much better than you might expect for how long and slack it is.

The Jeffsy Base is no lightweight at 33 lbs and 3 oz. It's an aluminum-framed trail bike with 150mm of front and rear wheel travel that retails for $2,300. While it may be heavier than our tester's personal carbon fiber super-bikes, it's a reasonable weight and quite similar to several other competitors in this review. If you're used to a lighter bike, it may feel a little portly; if not, you'll probably never notice. The geometry of this bike is as good on the uphill as it is the descents. The 77-degree effective seat tube angle is nice and steep, putting the rider right on top of the bottom bracket for direct and efficient transfer of power straight down into the pedals, and it feels great no matter how steep the trail gets. The 468mm reach is right about standard for a modern trail bike and provides a nice roomy and open cockpit, and when combined with the steep seat tube angle makes for a very comfortable seated pedaling position. The 1225mm wheelbase is definitely on the longer side, and this bike feels good when carrying a head of steam and motoring up and over obstacles in the trail. With a wheelbase that long and a slack-ish 66-degree head tube, our testers expected the Jeffsy to flail in tight technical terrain or sharp uphill switchbacks. Interestingly, it felt relatively nimble, with calm and predictable handling in those situations. That said, it's not automatic, and good line choices go a long way.

The pedal platform of the V4L suspension design is relatively calm and supportive. That's a good thing because the Deluxe Select rear shock that comes on the Jeffsy Base has a rebound adjustment only. There is no compression damping/climb switch for those fire roads or pavement grinds. There is some pedal bob when seated and climbing, though it is far from egregious, and it helps keep the rear wheel glued to the trail surface for excellent traction. Out of the saddle efforts result in more suspension movement, but no more than you'll find on most other bikes. The Maxxis Minion DHR II is a tester favorite, and while it may have a fair bit of rolling resistance, it provides excellent pedaling traction in a huge range of conditions. The SX Eagle drivetrain offers a huge range and plenty of low gears for tackling steep climbs. The YT-branded SDG Radar Mtn saddle was also surprisingly comfortable for sitting and grinding out long climbs.

Build

The Jeffsy Base 29 is built around YT's high modular alloy frame with their V4L (Virtual 4-Link) rear suspension design that controls the 150mm of travel. V4L is a 4-bar linkage design with its main pivot just behind the bottom bracket, pivots on the chainstays about two inches forward and slightly lower than the rear axle, and a rocker link about a third of the way up the seat tube. There are flip chips in the lower shock mount to adjust the head and seat tube angles by 0.5 degrees. The frame has I nternal cable routing, integrated downtube and chainstay protection, and can fit a Thirstmaster 4000 Fidlock water bottle (not a standard water bottle).

The suspension package of the Jeffsy is one of its greatest assets. The RockShox Yari RC features the Motion Control damper and has the same beefy chassis as the Lyrik. This fork feels excellent and is stiff and sturdy, giving the Jeffsy a confident and responsive front end. The RockShox Deluxe Select shock works well enough, although it features a rebound adjustment only. A compression damping/climbing switch on the rear shock would be nice, but it's not a deal-breaker.

YT did a great job choosing the wheels and tires on the Jeffsy Base. The DT Swiss M 1900 Spline wheels have a 30mm internal rim width, are tubeless-ready, feel well made and durable, and they have a very agreeable ride quality. The 20-degree freehub engagement isn't amazing, but these wheels are great for the price. A pair of Maxxis Minion DHR II EXO tires in a 2.4-inch width are mounted front and rear. These are beefy with excellent cornering, braking, and climbing traction and well-matched to the trail slaying intentions of the Jeffsy.

The cockpit setup is also on point and perfectly matched to this bike's performance. A 50mm Race Face Aeffect stem clamps a 780mm wide bar with a 20mm rise and beefy 35mm clamp diameter. A pair of ODI Elite Motion lock-on grips round out the front of the bike. YT started making/branding their own seatposts recently, and the Jeffsy comes with a Postman dropper in a 150mm length for the size large we tested (drop length varies by frame size). This dropper worked flawlessly for us during testing, and the 1x remote has good ergonomics and a light lever feel.

The Jeffsy Base comes with 4-piston SRAM Guide T brakes with a 200mm front and a 180mm rear rotor. The levers aren't our favorite, and we'd prefer something a little more powerful, but these brakes do work just fine. The weakest point of the build, in our opinion, is the SRAM SX Eagle drivetrain. While we're happy that 12-speed has trickled down to a budget price-point, it simply doesn't shift as well as it's higher-end siblings, and we have serious concerns about its long-term durability. Again, hard to complain, much, at this price.

Value

YT's consumer-direct sales model has allowed them to deliver unbeatable value for years, and there is no question that they are hitting a price to performance ratio that virtually no one can compete with. With a retail price of $2,299, the Jeffsy Base 29 is an incredible value. This is the best all-around bike we've tested under $2,500, with mostly awesome components that back up its performance. It easily outperforms bikes that cost significantly more.

Conclusion

If you're on a budget, but you still want to get a proper trail bike that absolutely rips, look no further than the Jeffsy Base. This 150mm travel 29er may be super affordable, but YT didn't cut any corners where it matters. This bike's updated geometry is dialed, and this bike is as versatile as the previous version and capable of charging way harder. The component spec is great for the price with the most important elements like the fork, cockpit, wheels, and tires up to the task of shredding hard. If you're looking for an aggressive yet impressively versatile and well-rounded trail bike, we think the Jeffsy is the best there is at this price.

Other Versions

The Jeffsy Base model we tested is available in sizes S-XXL in Black Magic (tested) and Twotone Blue. It also comes with either 29-inch wheels (tested) with 150mm of front and rear wheel travel, or with 27.5-inch wheels with 160mm of travel.

YT also makes three carbon models of the Jeffsy, all of which are available in 29-inch or 27.5-inch versions. The Jeffsy Comp is the least expensive model at $2,999. It comes with a Fox Float 36 Rhythm fork, a Float DPX2 shock, a SRAM NX Eagle drivetrain, SRAM Guide R brakes, and an e*13 TRS wheelset.

The Jeffsy Pro retails for $3,899 and comes with a RockShox Pike Select+ fork, RockShox Super Deluxe Select+ shock, SRAM G2 RSC brakes, a SRAM GX Eagle drivetrain, and e*13 TRS+ wheels.