YT Decoy Core 4 first-ride review: new Decoy is easy to ride fast thanks to Bosch motor and raft of updates

There are a lot of changes on this latest version of the YT Decoy, but what remains is its hard-hitting, downhill intentions.

One of the most significant alterations is the switch to the Bosch Performance Line CX motor.

Thanks to a recent update, this now pumps out 750W of peak power and a massive 100Nm of torque. YT has coupled this with Bosch’s biggest 800Wh battery to maximise the range of the new Decoy.

As you’d expect, though, there’s more to it than just a drive unit update.

Travel has been upped at the rear from 165mm to 170mm, while at the front it has risen from 170mm to 180mm.

The geometry has been given a thorough makeover and is designed specifically around mixed-sized wheels.

Out in the hills, the Decoy Core 4 feels easy to jump on and ride hard from the get-go.

There’s bags of travel and a balanced suspension feel, alongside geometry that works well when the going gets steep.

On top of that, there’s Bosch’s impressive motor, which delivers when it comes to power and control.

YT Decoy Core 4 motor and battery

It’s all change for the Decoy when it comes to the drive unit.

This latest bike has ditched the Shimano EP801 motor in favour of the gen 5 Bosch Performance Line CX.

Thanks to the recent firmware update, the Bosch system can now deliver peak power of 750W, maximum torque of 100Nm and up to 400 per cent assistance.

The motor's weight is claimed to be 2.8kg.

Powering all of this is the 800Wh-capacity Bosch PowerTube.

There’s a Bosch Kiox 400C display neatly integrated into the Decoy’s top tube, which can deliver just about all the ride data you need, along with motor modes and route-planning app compatibility.

A wireless mini remote mounts to the bar for quick and efficient mode changes, including the most recently added eMTB+ mode.

This adaptive setting is a little punchier than the standard eMTB mode, accessing more assistance more easily.

YT Decoy Core 4 frame and suspension

The new Decoy is constructed from YT's priciest ‘Ultra Modulus’ carbon fibre and designed around mixed wheel sizes – 29in up front, 27.5in at the rear.

No matter which build option you go for, you’ll get the same carbon frame.

The 170mm of rear-wheel travel is delivered using YT's V4L four-bar linkage system, which has been tweaked to make the bike more efficient to pedal around the sag point, despite being incredibly sensitive and supple.

Inside the frame are new top and bottom battery mounts. The upper mount now includes a rubber bush, that the YT team says is like the small rubber puck you’d find in a skateboard truck.

This is designed to add some give and reduce forces on the battery as the frame flexes when experiencing really high loads – something that can cause issues with connectivity.

There’s also a new, better-sealed charging port, which looks akin to a counter-sunk fuel cap on a car or washing machine drainage plug. This requires a twist to open and close, with a distinct ‘click’ once it’s locked back in place.

The cable routing has also seen some improvements, with new cable intakes and integrated, bonded inner tubes for the hoses and cables to run through, in a bid to keep the new Decoy as quiet as possible.

Along with plenty of rubberised frame protection, the revised skid plate on the underside of the down tube and bottom bracket is designed to direct air in to help cool the motor, and ensure there’s an exit for any mud or water that may make its way under it.

Finally, there’s YT’s Thirstmaster 2000 bottle, which offers 475ml capacity.

Because there’s only room for a bottle of this size, it means you won't be able to fit a range extender if you’re looking to boost battery capacity.

YT Decoy Core 4 geometry

Because the previous Decoy hadn’t been updated for a while, the geometry was in need of a refresh.

YT has increased reach by around 16mm across all sizes, upped stack by 22mm, lengthened chainstays by 3mm, shortened seat tubes by 20mm, dropped the bottom bracket height by 6mm, steepened the seat tube angle by a couple of degrees and slackened the head tube angle.

That means, for the size-medium bike I rode on the launch in the regular setting (there are two flip chip positions to choose from – ‘regular’ and ‘low’), you can expect a reach of 455mm. Stack is 648mm, with a 445mm chainstay length (which is the same across all sizes), a head tube angle of 64 degrees, an effective seat tube angle of 78.1 degrees and a bottom bracket height of 346mm.

Switch into the lower setting and you’ll slacken the head angle by 0.5 degrees and do the same to the effective seat tube angle. It’ll also drop the bottom bracket by 8mm, knock 6mm off the reach and add 4mm to the stack.

Frame sizes now range from small up to double extra-large.

YT Decoy Core 4 specifications

The Core 4 is YT’s top-end Decoy build and comes dripping with some of the nicest kit going.

Fox takes care of suspension, with the massive 180mm-travel 38 Factory fork up front and new X2 Factory shock at the rear.

SRAM provides its X0 Eagle AXS Transmission wireless gearing and Maven Silver brakes, complete with whopping 220mm front and 200mm rotors.

Continental’s Kryptotal front- and rear-specific tyres wrap the DT Swiss HXC 1500 wheels.

Although the bike I rode used a downhill-casing tyre on the rear, the Decoy will, as standard, come with the lighter enduro-casing options, using a Super Soft compound at the front and faster-rolling Soft compound at the rear.

The claimed weight for the Core 4 in size large, without pedals, is 23.2kg.

YT Decoy Core 4 ride impressions

YT Decoy Core 4 climbing performance

It’s important to point out from the get-go that I felt comfortable as soon as I jumped on the Decoy.

Like other YTs I’ve tested, there’s something reassuringly comfortable about the feel of the bike that leaves you oddly familiar with it, even though it has been overhauled.

That means getting up to speed and feeling confident takes minutes rather than hours, which is great.

With the updates applied to the Bosch motor and access to the new eMTB+ mode, the Decoy is rapid on the climbs thanks to all the power on tap.

That’s not to say it’s some kind of unwieldy beast that’s hard to control, though.

Bosch’s reputation for creating some of the best eMTB motors, with a very natural feel and plenty of control over power delivery, is still very much alive and kicking here, even with the extra watts available.

It helps that the steep seat tube angle of the Decoy sits you right up over the bottom bracket, enabling you to comfortably spin the cranks efficiently, especially compared to the previous bike that we criticised for its more laid-back seated position.

The longer rear end helps here, too, helping to balance your weight better between the wheels and lowering the likelihood of the front wheel lifting on steeper gradients.

Slow, technical sections can be tackled with plenty of poise and control. All that torque enables you to spin the cranks at a lower cadence but ensures there’s more than enough power getting to the rear tyre, making those awkward, low-speed manoeuvres that bit easier.

The suspension feels suitably active while scampering over rough inclines, beavering away and keeping the rear tyre in contact with the dirt.

YT Decoy Core 4 descending performance

Just as YT promises, the descent-focused DNA shines through when the Decoy is pointed downhill.

In choppy, rocky terrain, this bike makes you feel like a hero, enabling you to ride with precision and confidence.

It’s solid, balanced and planted, and won’t wince when you plough head-on into seriously ugly terrain.

The low-slung weight and well-portioned geometry boost cornering confidence. Get on the powerful Maven brakes early, set up ready for the turn, pick a line and the Decoy does a good job of keeping you on it while you cut through the apex.

On slower, more technical sections, the robust frame can feel quite direct, doling out feedback through the bar and pedals.

This means not everything beneath the tyres is muted quite as much as expected. As a result, I found I needed to be deliberate and aggressive with my riding in order to keep the tyres gripping when tackling awkward cambers littered with holes.

That feedback isn’t uncomfortable, though, because there’s plenty of plush travel on tap to help protect you from vibrations and impacts. It just meant on one particular trail, I felt I needed to be more zoned in and less passive when it came to keeping the tyres gripping.

However, lift the speed or steepen the gradient and the Decoy comes into its own.

The hands-to-feet relationship produces a confident stance on the bike that feels like a commanding position to tackle seriously tricky terrain from.

Whether ripping into steep, undulating sections that point straight down the hillside, or belting into high-speed rock gardens, sitting behind the Decoy’s bars felt like a safe place to be.

It’ll handle square-edge hits admirably, along with poor line choice and heavy landings.

There’s so much support through the suspension stroke and enough control deep into the travel that you're unlikely to get out of your depth.

YT Decoy Core 4 initial verdict

And that was the takeaway from my two days riding. The new Decoy feels easy to ride, composed when it needs to and above all else, confident.

It’s solidly built and feels like it can take one hell of a pounding.