The New YT Jeffsy Base Alloy All-Mountain Bike [In for Test]

We recently received the new YT Jeffsy Base 29er to test, and aim to see how this affordable alloy mountain bike performs over the next few months.

Readers often ask us to review affordable mountain bikes, and we aim to please. This YT Jeffsy base model retails for €/$2,299, making it the least expensive bike on the German brand’s website. I recently received the new Jeffsy Base 29er from YT Industries and plan to burn through its tires and brake pads over the next couple of months. Winter has decided to hibernate where I live, and our trails are open and dusty, resulting in the perfect testing grounds for a few lucky bikes.

The Base alloy 29er model is armed with a 150mm RockShox Yari RC fork and Deluxe Select shock, a SRAM Eagle SX 1×12-speed drivetrain, SRAM Guide T brakes, the ever-trusty DT Swiss M1900 wheels, a house brand YT Postman dropper, and a set of Maxxis Minion DHR II tires. I might be most excited about the tire spec, as I have recently come to appreciate the DHR II as a front tire, both for its braking traction and its square edge grip on off-camber trails.

I had a first-generation carbon Jeffsy a few years back, and I am stoked to see that the geometry has drastically improved on this azure alloy update. The Jefffsy maintains its flip-chip geometry adjustment and the headtube is a proper 66.5° in the high mode and 66° with the chip flipped to the low setting. The seat tube similarly morphs between a steep 77.5° and 77° respectively. With a stabilizing BB drop measurement of 32mm in the low setting and 24mm in high, I will not likely be spending much time with the bike in high mode. That BB drop squats between a 1204mm wheelbase on this size medium frame, with an average length 450mm reach, and switchback-snappy 435mm chainstays.

So much grip on these blocky Maxxis Minion DHR II tires.

One of the many elements I am interested in testing on this bike is the rear shock. With no external compression adjustment whatsoever, and only a rebound knob and air valve to dial it in, getting the air pressure right is going to be more important than with most other shocks. The Jeffsy Base doesn’t ship with any volume spacers for the shock, which makes me think YT is confident in the support their initial tune provides. So far it feels quite good with 25% sag, though I may add air for longer climbs depending on how that additional pressure affects traction and travel while descending. This Base model is largely marketed at riders who are less likely to be concerned with their shock tune, but as they start to ride harder and faster it will become more important.

The rear brake mount follows the current industry standard with a 180mm post-mount.

Stay tuned for our full video and written review in a few months.

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