It’s been almost 5 years since Christopher Walken graced the mountain bike world with his presence, meaning it’s been almost 5 years since the YT Jeffsy saw an update. This was arguably one of the more outstanding bike release videos we’ve seen, but at a certain point the bike has to live up to the hype. With a whole-cloth revamp the Jeffsy platform, YT aims to keep the train rolling and deliver a bike that will stay relevant and memorable for as long as that Walken edit.
The main theme of the Jeffsy is alive and well: a 29er trail bike that’s meant to get along with just about anything you might encounter out there in the woods.
Jeffsy Details
• Carbon or aluminum frame
• 29″ wheels
• 145mm travel, 150mm fork
• 65° head angle
• 77.9° seat angle (size specific)
• 435-515mm reach, 475mm size L
• Size-specific chainstay length
• High-low flip chip
• Measured weight: 34.4lbs
• $2,799-$6,499 USD
• yt-industries.com
I’ll be talking about the Large frame in Low mode, for now.
Geometry
Given the all-mountain/trail purview of Jeffsy, the geometry of the Low mode seemed a better fit for my terrain and preference. In time I’ll try the High settings out, but for now the bike feels too good to change things up quite yet. The numbers for this new YT feel quite correct for the up and down nature of the bike, with a good mix of length and sharpness to keep stability and excitement in balance.
The 65° head angle is becoming pretty typical of bikes in this range of travel, and makes for something that is stable enough in steep terrain while still feeling lively on flatter sections. The actual seat angles vary depending on size in order to hit the 77.2° mark at the average saddle height for a given frame. This is a smart approach, taking actual rider dimensions into consideration, as opposed to simply achieving a given number on paper without factoring setup changes.
In the 5-size range, the smallest 3 get 437mm chainstays, with the larger 2 jumping up to 442mm. While not exactly a perfectly size-specific approach, it at least addresses the shift in balance from the smallest to the largest reaches in the range.
A note on sizing: based on the geo chart, I probably would have leaned towards the XL, but I find the Large fits me really well. Either size would work nicely, but for the terrain in Bellingham, I think the smaller wheelbase is more fun. If I were looking for all-out stability and a safer feel at speed, then I’d probably go with the XL.
Frame Features
In keeping with the times, Jeffsy’s third coming features a host of updates we’re seeing on many recently released models, with some clever and clean integration by the YT engineers. The most noticeable is probably the in-frame storage, which has been implemented in a slightly different way to other designs on the market. Instead of being the plate that also carries the water bottle, the storage hatch on the Jeffsy stands alone above the bottle, eliminating the eventual loosening or rattling that might accompany the dual-duty designs. The hole is fairly small, but it’s enough to get the two included ditty bags in and out, and can fit plenty of tools, snacks, and shiny pebbles.
Old Jeff now features a UDH dropout, which is convenient for both the Transmission compatibility and the increasing ubiquity of those aftermarket hangers. For those running cables, the frame features full tube-in-tube routing to make the job a whole lot easier.
Jeffsy Core 1 and 2 are the aluminum-framed options, and sadly those don’t include in-frame storage of any sort, though they do feature all the same geometry and kinematics of the higher-priced tiers. Core 4 and 5 come with a Crankbrothers SOS plug tool and stash strap attached to the upper frame mounts, as you can see on my test bike.
There are nice finishing touches on the frames, like the rubber bumpers to silence any cable rattle that might occur from undersized cables for the through-frame routing. This is a frustration I have with other implementations of that design, as it can be quite noisy despite looking clean.
Though it looks a bit tight, there’s plenty of room for a full-size water bottle in the frame, with potential to eek out a bit more room with a different bottle cage. As noted in the geometry chart, a quick trailside operation can take you from the Low to the High mode, serving as the only adjustment available on the frame.
Suspension Design
YT is sticking with their typical suspension layout for the Jeffsy, opting instead to tweak the points slightly to make the bike as well-rounded as they could. Sag is optimized around 30%, with anti-squat falling around 105% at that point. The bike is more progressive than its predecessor, without jumping the shark and going for a rate that loses predictability and support.
Build Kits
We talk a lot about the comparative value of brick and mortar bike shop brands versus the no-longer-new direct to consumer model, but with some of the most traditional brands out there opening direct sales channels, that comparison has gotten a bit murky. Suffice to say that a DTC brand like YT can still offer value that most shop model brands can’t compete with, as is the case with the new Jeffsy. Topping out at $6,499 USD, Jeffsy lineup has 5 well-specced tiers that cater to a wide array of budgets, depending on price, experience level, and component preference.
Ride Impressions
I had an excellent first ride on the Jeffsy, and the positive feeling hasn’t waned much since that day. From quick laps on my local favorites to longer, very technical rides, the bike has felt predictable, fun, and simply easy to ride. YT seems to have nailed the tricky balance of a bike that is easy to cruise on while still holding its own when pushed hard or thrown into more serious terrain.
Climbing feels supportive and efficient, without giving up too much grip, and remains active over technical terrain in and out of the saddle. Descending is intuitive and well balanced, with excellent cornering performance and great pop on jumps and jibs. The 145mm of rear travel is well managed, with only a few bottom-outs on some very serious hits. The bike has an active feel through chattery terrain, especially when you let off the brakes and push through the bike.
An immediate takeaway was just how quiet the Jeffsy is, with no rattles, creaks, or other annoyances developing over the past couple weeks of riding. Another rosy first impression is the dialed build kit – there’s nothing I’d change out of the gate on my Core 4 test bike. The brakes, drivetrain, suspension, wheelset, and cockpit are all pretty close to what I’d choose for a bike of this ilk, so I’m more than happy to stick with the stock options.
