The YT Decoy, one of our former eMTB of the Year winners, now comes with a beefier battery for increased ride capacity

Product Overview

Overall rating:

Score 8

YT Decoy Core 4 MX


  • 720Wh battery means more fun, reactive ride, premium build components


  • 720Wh battery means more money


YT Decoy Core 4 MX e-bike review


Price as reviewed:


Say hello to the 2023 YT Decoy Core 4 MK 1.35. Okay, so the MK1.35 tag isn’t part of its official title, we added that ourselves. But seeing as YT has managed to increase the potential battery capacity from 540Wh to 720Wh (which is a 35% increase) without having to make wholesale changes to the frame, we think it’s a rather fitting addition.

Need to know:

  • A flip-chip in the rearward shock mount offers high and low geometry settings
  • Tested here with the new 720Wh battery, but the bike ships with the old 540Wh battery
  • Mixed wheelsize
  • Full carbon frame comes in five sizes – S to XXL
  • Fox Factory suspension has all the adjustability you need and then some

YT Decoy Core MX 4

How did YT squeeze in the extra juice without messing up the handing of our e-bike of the Year winner in 2021? It completely redesigned the battery, while maintaining the same fittings and mounting architecture. So yes, the new 720Wh battery is backwards compatible with all Decoy models, bar the size S. It’s currently only available as a standalone product for £899, which, as e-bike batteries go, is competitively priced.

Best of all, the potbelly profile of the 720Wh battery allows YT up the cell count while keeping the extra weight as low and central in the bike as possible. On our scales the 720Wh battery weighed 4.57kg, which is 860g heavier than the stock 540Wh battery, and increased the weight of the stock Decoy Core 4 from 23.32kg to 24.18kg. Still pretty competitive, but not as light as you might expect for a full carbon frame and high-end build kit that wants for nothing.

YT Decoy Core MX 4

Still it’s a moot point as all current Decoys ship with 540Wh batteries as standard, but we’re confident that YT will roll out the bikes with the new battery in the not too distant future.

Other than the bigger battery option then, it’s business as usual since we last tested the Decoy. It’s still available in MX (170/165mm travel) and full 29in (150/145mm travel) options and it’s designed around the Shimano Steps EP8 motor, with the smaller, monochrome SE E7000 display.

YT Decoy Core MX 4

The frame is available in five sizes XS to XXL and while the sizing on the Decoy isn’t the most generous, the size L sporting a rather demure 451mm reach, the Decoy feels all the more manageable and manoeuvrable for it. Also the 50mm stem ensures that the fit never feels cramped, and even slows the steering response down a hair to make it easier to correct course mid turn.


As the flagship bike in the Decoy range, the Core 4 get’s Fox Factory level suspension components, bling Kashima coating and all. The 170mm Fox 38 fork and X2 shock both offer 4-way adjustable damping, so if you want a flatter, more stable ride to the Decoy it is relatively easy to achieve by simply cranking up the compression damping.

YT Decoy Core MX 4

However, we think the Decoy feels best with a lighter more active approach to the oil flow, as it makes the bike feel really reactive and playful. And the cool thing about all of the adjustability on Fox’s top-tier suspension is that you can have it either way, or somewhere in between.

YT Decoy Core MX 4

We are not normally big fans of compression levers, especially on ebikes, but the one on the Fox X2 shock is actually pretty useful on the Decoy for climbing, primarily because the relatively slack 75.5º seat angle makes it harder to keep your weight forward on the steepest assents. So being able to prop the rear suspension up easily is really helpful.

YT Decoy Core MX 4

In our workshop we could only squeeze 160mm travel out of YT’s four-bar suspension, which is 5mm less than claimed. On the trail however, it offers a very composed ride. It’s not quite as pitter-patter as the Vitus, but the YT holds its poise slightly better so you can still charge really hard on it. It’s a slightly harsher ride too, maybe due to extra stiffness of the full carbon frame, as it’s most noticeable when the bike is lent over in a turn.


Continuing with the Gucci build are CrankBrothers Synthesis alloy wheels, in an MX e-Bike format. Freehub engagement with the i9 1/1 rear hub is ultra fast and secure, and while Synthesis wheels typically have different rim widths front and rear, both rims on the e-bike hoops have 31.5mm internal widths.

YT Decoy Core MX 4

Tyre casings has been increased over previous generations of Decoy, and it now sports Maxxis EXO+ casings front and rear, where previously an EXO casing front tyre was used to save weight, or possibly even money. Either way, it’s a good move and hard chargers will probably want to increase the level of protection on the rear tyre to a Maxxis Double Down or similar to improve pinch flat protection further.

What YT offers with increased range in one hand it takes away with the other by adding a softer compound MaxxGrip front tyre. Still, it’s a great option for wet and wild conditions.

YT Decoy Core MX 4

YT has also increased the drop to 170mm on the Postman dropper for the size L bike, and the post has a really smooth, light lever action. The icing on the cake is the well padded SDG Bel Air 3.0 saddle with its subtle whaletail making it the perfect complement to any e-bike.

Fast bikes need good brakes and the SRAM Code RSCs with 200mm rotors deliver. Not only do they have a much nicer lever feel than the Code RS brakes on the Canyon, which is mostly due to the bearings in the lever pivots, but the power was noticeably improved too.


The YT Decoy Core 4 offers a ride quality that’s every bit as peppy as the sharp clean lines of the full carbon frame. And for a bike that’s three years old, it still looks and feels contemporary.

YT Decoy Core MX 4

With all of the available suspension travel you’d half expect the Decoy to feel stuck to the ground like velcro. It’s not. Which makes it really easy to sack off a bad line choice and change direction in the blink of an eye.

The flip-side to that degree of reactivity is that it’s got an altogether tighter feel to the frame and suspension than either the Vitus or Canyon, so there’s more feedback though the bike and those oversized 35mm alloy Rental bars. On longer descents this generates more fatigue in your hands and it is why we recommend grips with a little more padding than the ODIs that come fitted as standard. Nit picking? Possibly, but it’s the only thing that’s wrong with the specification on the Core 4, so you tend to hone it on it, right?

YT Decoy Core MX 4

Actually that’s not the only thing that annoyed us with the Decoy. Even with the steering lock headset, Shimano’s plug and play cables kept popping out the SC-E7000 display every time we tweaked the bars. Eventually, one disconnected inside the frame so we had to remove the battery mount to reconnect it. The lights came back on for one ride, then the bike wouldn’t switch on again, probably because the bike was wet when we turned it upside down to reconnect the cable.

It’s the same reason why you should never turn the Decoy upside down to wash it, otherwise you’ll be left with a sitting duck.


For 2023 YT has gone to great lengths to increase the battery capacity of the Decoy and keep the bike current, or is that, keep the current bike? The real question is if the extra juice is worth the squeeze? In short, yes. But the new 720Wh battery doesn’t currently come stock with the bike, so you’re going to need to spend an additional £899 to get it.  Ultimately, things have moved on a fair bit since we last tested the Decoy, and while the ride quality is still up there, with only 540Wh of run time as standard, you’ll be riding around in eco mode, while all your mates whizz past you to squeeze in the extra laps.


Frame :Carbon, 165mm travel (160mm measured)
Shock :Fox Float X2 Factory (230x65mm)
Fork :Fox 38 Float Factory Grip 2, 51mm offset, 170mm travel
Motor :Shimano STEPS EP8 85Nm, 500W peak power
Battery :SMP YT Custom 540Wh 35V
Display :Shimano Steps SC-E7000 w/remote switch
Wheels :Crankbrothers i9 110/148mm hubs, Crankbrothers Synthesis alloy rims, Maxxis Assegai MG EXO+/ Minion DHR II MT EXO+ 29x2.5/27.5x2.6in tyres
Drivetrain: Shimano XT 36t, 160mm chainset, Shimano XT derailleur and 12sp shifter, Shimano M8100 XT 10-51t cassette
Brakes :SRAM Code RSC 4-piston, 200/200mm rotors
Components :Renthal FatBar 35 alloy 800mm bar, Renthal Apex 35 50mm stem, YT Postman 170mm post, SDG Bel Air 3.0 saddle
Sizes :S, M, L, XL, XXL
Weight :23.32kg (51.41lb)
Size tested :L (low)
Head angle :64.1°
Seat angle :71.2°
Eff SA :75.5°
BB height :342mm
Chainstay :442mm
Front centre :795mm
Wheelbase :1,237mm
Down tube :732mm
Seat tube :450mm
Top tube :610mm
Reach :451mm