YT Decoy Core 4 review – playful mullet e-MTB

The YT Decoy first landed in 2019 and despite having many different guises since then, it essentially still runs the same frame. While a fifth birthday this year could seem a little grizzled in mountain bike years, the Decoy is still one of the best electric mountain bikes around. I've been testing the Core 4 version recently and having a great time in the process.

Design and geometry

Despite being somewhat long in the tooth now, many of the Decoy's key geo numbers are still in line with more recent released incarnations of enduro/tough trail e-bikes from Canyon, Specialized, Trek, and others. However, the measurements where it falls down are the reach and wheelbase, which at 449mm on the large-sized bike I'm testing, is 30 to 40mm shorter than the Decoy's rivals, while the 1,235mm wheelbase falls short by 20 to 40mm depending on which bike you compare it too.

Longer bikes are inherently more stable than shorter ones, though the flipside of a more planted ride is a less poppy and playful one. I usually ride medium sized bikes, but the reach on the large Decoy still comes up shorter than what I'm used to these days.

As is now required on any modern MTB worth its salt, the Decoy comes with a geometry-adjusting flip-chip with high and low settings. This gives riders the option to change the head tube and seat tube angles by half a degree.

The suspension linkage design is YT's Virtual Four Link – a Horst-link system that YT says is designed to give a Goldilocks combination of small bump sensitivity, support in the mid-stroke, and plenty of progressivity at the end.

The 442mm chainstays are short for an e-MTB and combined with the mullet wheeled setup (29in front and 27.5in rear), help to enhance the Decoy's frisky nature. The hanger has been updated since the original and is now SRAM UDH.

An oversized downtube on the full carbon frame houses the battery which is easy to drop straight out by removing two retaining bolts. My test bike came with the 720Wh battery upgrade, but riders can still opt for the older and 860g lighter, 540Wh version.

Components and build

Unlike the more recently updated Core 1, 3, and 5 models, the Core 4 here runs Shimano's original EP8 motor (rather than the latest EP801) powered by a YT custom battery. Motor info is displayed on a low-profile LCD bar-mounted screen and Shimano's two-button power mode selector keeps things nice and simple.

The suspension comes in the form of top spec, e-MTB specific Fox 38 Factory fork with 170mm travel fork and Fox Factory X2 shock with 65mm of travel.

Higher spec YT bikes have used Crankbrothers rims and Industry 9 hubs for some time and the relationship continues here with 31.5mm internal width Synthesis Alloy rims on 1/1 enduro hubs. The wheels come shod with a triple compound Maxxis pairing of an Assegai 2.5, EXO, MaxxTerra front tire, and a Minion DHR II 27.5 x 2.6, EXO+ MaxxTerra rear.

There's no room for a full-size bottle on the frame given the shock and pivot position, but YT has cunningly manufactured a short, squat bottle that just about squeezes in place and holds 450ml of fluid – which is way more than it looks.

For more component details, see the full list at the bottom of this article.

Ride and performance

I tested the Decoy on a range of trails from local singletrack to semi-natural, steep enduro runs, and the bike was a really fun and engaging ride over it all. The short reach and wheelbase combine with the capable suspension system to give a proper 'having a blast on just about everything' feel. It doesn't feel as assured as a longer bike on steep descents and I had to work harder on finding the best body position to stay centered, but the advantages of a shorter frame made it easier to flick through tighter turns, rail high-sided corners, and get the front wheel up. The extra agility enhances the fun factor when blasting technical climbs, though less reach meant I had to shuffle my weight around to maintain traction. At 23.73kg, for my large test bike, it's also relatively light for a big motor, big battery bike which helps to enhance the agile feel.

The supportive Fox suspension package sits high in its travel over smaller bumps but does an excellent job of soaking up larger hits – making it an excellent 'get out of jail free card' when the peppy handling encourages you too far out of your comfort zone, or you make a fore/aft body positioning mistake while airborne.

A mixed wheel setup is a big part of why the Core 4 Decoy feels so playful and I put this to the test by switching between it and a full 29er Decoy running identical wheels and tires (with different rear wheel dimensions of course) on the trail. While the 29er was noticeably more rapid when simply rolling down trails, with its smaller rear end, the mullet bike felt far more responsive and engaging when pumping and popping down runs in the usual way.

Despite most of my testing taking place over a particularly soggy fall/autumn and a very wet or very cold winter on rooty trails, I rarely lost a wheel. The triple compound, top spec MaxxGrip version of the Assegai was totally reliable up front while the slightly harder MaxxTerra Minion DHR II gave tons of traction too. That said, if you ride mostly rocky trails, you may well want to opt for the extra security of tires with tougher casings than the EXO (on the Assegai front) and EXO+ (on the DHR II rear).

The larger capacity 720Wh battery may add to the overall weight of the Decoy, but it's a sacrifice well worth making. Three hours of hammering up and down steep Exmoor terrain in cold weather would typically use up 65 to 70 percent of the battery when in Trail mode. My aching muscles would usually be asking me to call it a day way before I got to the point of wondering if I'd enough charge to make it to my van – unlike my mates on smaller batteries who would be nursing the little charge they had left.

Verdict

If you're looking for a confidence-inspiring and totally assured enduro slayer to take on serious steeps, then YT's Decoy is not the bike for you. However, if you want a capable and lively, full fat e-MTB that's as far away from feeling like an electric monster truck than anything else without a lightweight motor, then definitely give the YT Decoy serious consideration – as long as a short reach isn't an issue for you.

You definitely get a lot of bike for your money and YT is currently offering 25 percent off the entire Decoy range. Unfortunately, at the time of writing the Core 4 model isn't currently available as it wasn't part of the updated Decoy line-up with Shimano Free Shift tech announced in late 2023. The Core 4 option still features heavily in YT's other ranges though, so it's not a massive leap to imagine that this model will be appearing in one guise or another once again.

Tech specs: YT Decoy Core 4

• Price: £7,499 / £6,999 / €6,999
• Frame: Full carbon, Boost width axle, UDH hanger
• Fork: Fox 38 Factory E, 170mm travel, GRIP2 damper, 51mm offset, Boost
• Shock: Fox Factory X2 65mm travel
• Motor: Shimano EP8
• Battery: SMP YT Custom 720Wh
• Head angle: 64.1 / 65 degrees
• Seat angle: 75.5 / 76 degrees
• Reach: 449mm (size large)
• Crankset: Shimano XT, 160mm arms, 36T chainring
• Gearing: Shimano XT 1x12, M8100 Shadow Plus, 10-51T XT Microspline cassette
• Wheels: Crankbrothers Synthesis Alloy rims, 31.5mm inner width, with i9 1/1 hubs
• Tires: Maxxis Assegai 29 x 2.5, EXO, MaxxGrip 3C front, Maxxis Minion DHR II 27.5 x 2.6, EXO+ MaxxTerra 3C rear
• Brakes: SRAM Code RSC, 200mm rotors
• Bars: Renthal Fatbar 35, 800mm wide, 35mm bore
• Stem: Renthal Apex 35, 50mm
• Seatpost: YT Postman, 125mm drop size S, 150mm M, 170mm L – XXL
• Saddle: SDG Bel Air 3.0
• Sizes: S, M, L, XL, XXL
• Weight: 23.73kg (size large tested)