2022 YT Decoy MX Core 4 E-Bike

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At first glance the YT Decoy MX Core 4 looks like a dream machine. A downhill bike that can be pedaled uphill? Could it be that our dreams have finally come true? As we dug further into YT's mixed-wheel e-bike, we found there was more nuance to be explored. We've spent months exploring the west with this consumer-direct eMTB and are ready to share the full rundown on how the YT held up.

Highlights

• Carbon frame
• 29-inch front wheel // 27.5-inch rear
• 165mm (6.50-inches) rear-wheel travel // 170mm (6.69-inches) fork travel
• Virtual Four Link suspension design
• Internal cable routing
• Powerswitch integrated into frame to protect from dirt and damage
• Shimano Steps EP8 motor with 85 NM of torque and 250W
• 540 Wh YT Custom Fully Integrated Battery
• Acros BlockLock headset limits movement of fork to protect the frame
• 148mm rear spacing with 12mm through axle
• Measured weight (size medium, no pedals): 50 pounds (22.7kg)
• MSRP $7,999 USD

YT’s Decoy MX Core 4 looks like a bike made to rip. It is aggressive and has a powerful Shimano EP8 motor to rally to the top of otherwise long climbs. YT has used a custom battery shape to reduce bulk and make for a sleeker-looking downtube. At the top of the downtube is the charging port for the battery. Integrated into the top tube is the power switch. This keeps it out of the way of dirt and other debris that could cause damage. The internal cable routing also looks sharp and the bike comes with clips to keep the cables organized.

Geometry

Just like the mix of 29 and 27.5-inch wheels, the Decoy MX Core 4 is a mix of current downhill and trail bike geometry. It is also an example of not being able to judge the ride solely based on the numbers. It has the slack seat tube angle of a DH bike and the headtube angle of an aggressive trail bike. Chainstay length falls somewhere in the middle. The one spec that stood out as an outlier was the wheelbase. Based on the ride we wouldn’t have expected it to be relatively short. We'll unpack all of this later but for now, don't let the Decoy's numbers trip you up.

Setup

As with other YT bikes, the Decoy is going to show up at your house in a box. Fortunately, they are about 95% put together. Additionally, YT sends tools and torque specs to make it easier. Unpacking and assembly to our liking took about an hour and a half.

The initial setup went through a few steps. First, we left the flip-chip in the lower, more aggressive setting with a slacker head tube angle and lower bottom bracket. We were down to party. We then proceeded to suspension setup followed by cockpit adjustments. For suspension, we generally followed the FOX recommended settings. Our FOX 38 was pumped to 75psi which is in the recommended range of 72psi to 80psi for our weight. Both low and high-speed rebounds were set at 6 clicks from full close. These turned out to be a little slow but more on that later. The rear suspension was set to 30% sag at 150psi. Rebound was 9 out from full close. Low and high speed were both set at 8 from full close. Each of these rear suspension settings was in the middle of the range of clicks.

The last to-do was cockpit setup. We spent a few minutes adjusting lever angles and then hopped on to pedal around in the street. The initial feel of the cockpit was spacious. There was room to move around but would still need a few comfort tweaks. The stock Renthal Fatbar 35 is 800mm wide (31.5in) so it needed to be trimmed down a bit. They were cut down an inch total to 775mm (30.5in). We also felt the need to slam the seat forward to compensate for the slack seat tube angle. It felt like we were pedaling in the backseat initially. After making these few tweaks the Decoy was trail ready.

One extra step that we must consider with e-bikes is the motor setup and app downloads. The app associated with the Shimano Steps EP8 motor is called Shimano E-Tube. Our Decoy was left in the factory settings for most of the test. Profile 2, as named in the app, meant that the 3 modes (Eco, Trail, and Boost) were relatively evenly spaced through the power. We have changed this on other bikes but on the Decoy, those settings felt pretty darn good.

Even though we didn’t make any early changes, we still recommend downloading and syncing the app during the initial setup. There are other features of the app that can be super helpful on trail. Arguably the best reason is to get access to the Error Code Log. Should something go wrong on the trail it will tell you what the code means and what can be done about it. There are other motor changes that are possible too such as dialing in the initial pick up speed. You can have the motor engage quickly or let the speed build over a few pedals strokes. The Decoy comes from YT with pickup speed set on high for all modes. Ok enough nerding out on the app, let’s go ride!

On The Trail

Trails Ridden

This Decoy MX Core 4 got to do a mini-tour of the west. We rode on trails in Reno, Denver, and NorCal. Trails in Reno were mostly wide open with some rocks but in general intermediate terrain.

For many of these trails, the Decoy was a bit overkill but on the rocks of UNR DH, it was super fun. Also in Reno is Sky Tavern. Trails here have a little mix of everything including a dual slalom. One thing we confirmed, the Decoy is not a slalom bike. It was more fun on trails such as College Boy that has some rocks, berms, and jumps.

...it was the most fun we have had on a bike in a while. Like laughter-inducing fun. Grins from ear to ear.

In Denver, the riding was at White Ranch and Chimney Gulch. White Ranch has a heinous climb called Belcher Hill that was made infinitely better by a motor. This gave us easy access to the techy Longhorn trail. The Decoy was made for Longhorn. This trail is steep, rocky, raw, and fast. It puts any bike to the test and the Decoy was able to rise to the challenge. Chimney Gulch was more about testing the technical climbing ability. This trail is steep to climb and has a lot of rock features to get up and over. Descending this trail also tests the suspension but unlike Longhorn, it is at much slower speeds.

NorCal found its way into the mix too. The riding here is more rooty and steep. This terrain was gobbled up by the Decoy as well. The trails here are steeper than anything we rode in Reno or Denver but we hardly noticed.

DH/Technical Performance/Fun Factor

One of the first things to get used to was the weight. Our Decoy felt cumbersome for a while. It was slow to respond and liked to keep going in a straight line. Looking back, these first few rides at Peavine in Reno just didn’t play to its strengths. This profile changed so much when it was pointed down steep and fast trails. Just like a downhill bike or moto, the Decoy needs some speed to feel lively. On the steep terrain of Longhorn or NorCal it was the most fun we have had on a bike in a while. Like laughter-inducing fun. Grins from ear to ear. Surprisingly, the FOX Factory suspension reminded us closely of our dirt bike. Rocks and roots felt like nothing and the weight was now a benefit, making the Decoy feel planted and stable.

While we got used to the weight on the trail over time, we couldn’t get past it when it came to jumping. The Decoy was very particular about flying. To be fair, we can’t say for sure if this would have changed with another few months on the bike but we don’t think so. It is very consistent in that speed helps it respond. Jumping seemed to go along with this. Coming in hot it would float over jumps just fine. But the cruising speed playful hits that can make a trail extra fun were a no-go on the Decoy.

Rear Suspension Performance

The FOX Float X2 Factory certainly contributed to the Decoy’s performance on techy, steep trails. As mentioned above, it has the feel of moto suspension. One of our local trails, UNR DH, has successive drops that are about 2 ft each. The Fox Float X2 Factory made those feel like small curbs. It was a soft landing each time and the few in a row didn’t do anything to upset the rear of the bike. It smoothed out chatter as well. Overall the downhill performance was pretty spot on.

Geometry

It is easy to see that the Decoy MX Core geometry is geared towards aggressive terrain. The mullet set up, the long-travel suspension, the slack headtube angle. But it wasn’t all straightforward and it took us a while to digest the numbers we were seeing and how they translated into the ride experience.

The most noticeable is that the seat tube angle is very slack at 76-degrees. So slack that it matches the seat tube angle of a Transition TR11. As mentioned in the climbing section, this took some getting used to. For lack of a better term, it was just plain weird to be sitting so far back. However, we adjusted fairly quickly and this didn’t negatively impact our ability to keep weight on the front wheel. Perhaps we were able to keep the front end down because at 429mm, the reach is on the shorter side compared to other size medium bikes we have been on.

We were also surprised by the wheelbase number. At 1,213mm we expected something longer given the stability at speed we were feeling. Maybe the weight helps? Or the mullet setup? We can’t definitively say but we do know that it works.

The Decoy comes with a flip-chip to change the geometry slightly. It results in a 0.5-degree steeper headtube angle and a slightly higher bottom bracket. Looking back through our test we did notice a few more pedal strikes than usual but if we are being honest, we aren’t sure we can blame the bike. The difference in speed changes pedal timing so we can’t completely rule out user error. For someone who is pedaling in consistently rocky terrain, it might be worth flipping to the high setting if they are also experiencing strikes. This flip-chip also changes the headtube angle from 64.5 to 65-degrees. This is in line with most trail bikes today. As a result, the Decoy didn't have a hard time with the front end wandering on steep climbs, despite being in the backseat.

Perceived Weight

There is no way around it, the Decoy is heavy. It feels heavy loading it in the truck and out on the trail at slow speeds. But obviously, this is where the motor comes in. The weight becomes less of an issue at speed. The Decoy is not snappy, nor is it meant to be, but it can still be super fun despite the weight.

Sprinting

Sprinting on the Decoy was incredibly underwhelming. With the pickup set at max in the E-Tube app, it seemed that it should crush sprints. Sadly, it did not. The motor seemed to cut out well below the 20mph cutoff for speed. The Decoy is more about marathons than sprints.

Climbing

Climbing on the Decoy was a breeze over smooth terrain thanks to the motor but it was an interesting experience on technical climbs. This was one of those weird muscle memory things. Pedal timing combined with gearing was very different from what we are used to. In order to get the most efficiency out of the motor, a higher cadence must be kept. For us, this meant easier gearing but this isn’t always the answer to balance up-and-over rocks. It took quite a bit of trial and error to settle on the fact that Eco mode has the most natural feel and was the preferred mode for tech climbs. The bike tended to toss us around through rocks at the higher power modes. There was almost too much power to maintain precision. It actually felt as if the bike needed a distinct rear suspension tune for climbing alone.

Motor and Battery

Onboard the Decoy is the Shimano Steps EP8 motor. At 85 NM torque, it is now 300 grams less weight and 10% less volume than previous models. According to YT, noise has also been reduced. While we can’t speak on any previous models, it does seem to be quiet compared to other e-bikes we have tested.

Battery life on the Decoy can be summed up in one word - impressive. It was a shock how many miles and how much vert could be logged without killing the battery. Here are some ride stats as an example: the Decoy in Eco mode went on two rides that logged just under 20 miles with 3600 feet of climbing and only used 3 bars of 5. Another ride of 10.5 miles with 1620 feet of climbing all on Boost mode only used 1 bar of battery life.

The majority of the miles on the Decoy have been in Eco so this does contribute to longer battery life. However, battery life could be extended using the Shimano E-Tube app to dial back the Eco mode power delivery. If longer battery range for all-day adventures is your thing then certainly work with the app to maximize miles. If you are looking to get to the top as fast as possible to rip the descent, dial up the Boost a bit. The app allows you to customize your ride in so many ways.

Lastly, a neat feature of the battery is that it can be charged on or off the bike. Two bolts in the downtube hold everything in place but they can be removed. The cover for the battery is also replaceable should it get damaged.

E-Bike Tech

For the most part, everything on the tech side worked as it should. The app was easy to sync and is user-friendly. We did have one mid-ride error code. It was error “E050” which means that “an abnormal bicycle speed signal was detected from the speed sensor.” Admittedly when we got this error we did not have our phone with us. Doh! If we had, we could have checked the app and found a description right there. Instead, we just decided we might need to go back to the car and were not looking forward to the pedal out. However, after pointing the bike downhill for a few minutes the error cleared and our ride was saved. After that, we didn’t have any more glitches. And checking the error log at the end of the test, this is still the only one showing up.

There isn’t much to the Shimano E7000 display and we like that. It simply shows what mode you are in, the amount of battery left, and your current speed. Simple, easy to glance at and process and it worked great the whole time.

Build Kit

The build on the MX Core 4 reflects its position as the highest level spec of the line. Included are a Shimano XT drivetrain, SRAM Code RSC brakes, Renthal bars/stem, and Crankbrothers wheels. The only part of this spec that stood out as a negative is the choice to have the YT Postmaster dropper at 125mm drop for size medium. We found ourselves having to manually drop the seatpost into the frame to feel totally in control for steeps and jumps.

Fork Performance

The FOX 38 Float Factory E-Bike+ with a Grip2 damper provided smooth support to the front end. This fork is soft off the top but was able to provide the support needed for the hits this bike is meant to take. It wasn’t perfect right off that bat though. Our initial setup had the rebound a bit too slow. This resulted in punishing feedback through our hands. We ended up with our low-speed rebound 9 clicks from close and high speed 8 clicks from closed. There is a total of 10 clicks on both. After this correction, the feedback went away and we didn’t have any other issues with setup or performance.

Tire Performance

The Maxxis Assegai at 2.5-inch WT with EXO casing and 3C MaxxTerra compound provided a lot of confidence through loose and dry terrain. The front-end traction was very predictable.

In the back is a 2.6-inch Maxxis Minion DHRII with EXO+ casing and 3C MaxxTerra compound. The combination of plus-sized tires with aggressive tread allowed for lots of traction and the fact that this is an E-bike made rolling resistance concerns a moot point. We will say that it is a bit surprising that YT didn’t choose to use the Double Down over EXO. It would make more sense to spec this casing at least on the rear wheel.

Wheel Performance

The Crankbrothers Synthesis Alloy E-MTB wheels were an interesting choice for this bike but only because it isn’t often that you see Crankbrothers wheels on a factory spec sheet. At a rim width of 31.5mm, they paired well with the plus-sized tires. They stayed true through our test and we didn’t notice any major dings, surprisingly. The rear wheel is laced with an i9 1/1 Microspline and had a decent engagement. Overall we didn’t notice too much about the wheels which we kind of take as a good thing. They performed well, didn’t give us any issues, and didn’t raise any red flags for the duration of our test.

Brake Performance

One big swing and a miss with the Decoy spec was the brakes. The SRAM Code RSC brakes were a bit underpowered for how fast this bike really wants to go. The Decoy comes stock with 200mm rotors front and rear so we think there would be a benefit to sizing those up to 220mm. The Codes were also slightly squishy from the factory. Something to consider when building up the bike would be a bleed right out of the box.

Drivetrain Performance

Continuing with the suggestion to work with your local shop, the drivetrain might need a bit of a tune right out of the box. It took a few rides but once the cables stretched a bit the derailleur was out of tune. It was having some issues shifting and skipping gears but this probably could have been avoided by a better tune right out of the box.

Noise

There was a symphony of sounds coming from the back end of this bike on descents. The chain would slap and the wheels were pinging. Fortunately, the wheel noise could probably be remedied with CushCore or another tire insert.

The two parts that we would swap on the Decoy are the YT Postmaster seatpost and the SRAM Code RSC brakes, or at least upsize the rotors. The YT Postmaster at 125mm of drop does not allow for enough room to move around on the medium frame. And the brakes need a bit more oomph to keep up with the way this bike is capable of being ridden.

Long Term Durability

Looking long term there isn’t anything that stands out as a red flag. While we didn’t love the brakes or the dropper, there is nothing that would cause us concern over the long term. Other components are well known so there shouldn’t be any surprises there. However, should anything arise with the frame there is a 5-year manufacturer’s warranty on defects for the original owner.

What's The Bottom Line?

The YT Decoy was a harder bike to nail down than we thought it would be. It doesn’t handle technical climbing too well yet rips in techy descents. Doesn’t like to jump but feels stable at speed. Throw in the weird spec choices like the short dropper seatpost and lack of a tougher rear tire casing and that muddies the water even more.

While this bike might not be for everyone and every trail, it is going to put a grin on the face of someone who wants to rally up a fire road to lots of gnarly steep descents. This could also put a huge smile on the face of someone coming to mountain bikes from a moto background where the weight won’t be as much of an issue.

YT has long had a reputation for offering a lot of bike at an affordable price. The Decoy MX Core 4 is no exception. Comparable builds with other brands are going to cost you at least $1k more at this highest level. Add this value to all of the smiles that riders will have with the YT Decoy and it equals a whole lot of Good Times.

Head to yt-industries.com to check out the Decoy line.

About The Reviewer

Amanda Wentz - Age: 40 // Years Riding MTB: 15? // Height: 5'6" (1.67m) // Weight: 130-pounds (58.9kg)

Amanda Wentz started out mountain biking as an escape from the drudgery of half-Ironman training and endurance sports. After finding her love of technical terrain, downhill racing followed suit. A few high points of Pro GRT podiums and a 5th at National Championships rounded out most of her racing, and now she enjoys pushing herself without a clock. Currently, finding the big mountain rides light her spirit, wherever those mountains may be. Amanda is based in Reno, NV or anywhere else across the mountain West she may adventure to ride bikes.