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(The Gear Loop) - The concept of an electric mountain bike is nothing new. After all, brands like Specialized, Giant, Canyon, Scott and many more all boast lithe, electrified versions of their best cross-country and downhill machines.

Again, the notion of an electric motocross bike has also been explored by brands like KTM and new comers Cake, but the alluring, otherworldly place that sits somewhere in the middle is where Australian brand Stealth operates.

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Designed and manufactured in the wilds of Oz, these mean looking trail monsters pinch styling elements (and components) from the mountain bike scene, but beefs up proceedings by also borrowing parts from the motorcycle world.

The Stealth F-37, as tested here, is the latest 2022 model and packs a powerful 2,000W motor that sits in the rear wheel and delivers a punch 120Nm of maximum torque. It is operated by a twist throttle on the handlebar and proceedings are brought to an abrupt halt by whopping motocross hydraulic disc brakes.

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Throw in monster 180mm travel front forks and an equally enormous adjustable rear spring and you have a set-up that will happily tear up trails, soar over jumps and general act the yob for around 40-miles before the batteries run dry and spoil the fun. Oh, did we also mention it can hit almost 40mph? Yeah, it’s rude.

£7,699 | Buy from Ride & Glide

Our quick take

There is no denying the Stealth F-37 is huge amounts of fun to ride, uniquely blending elements of mountain-biking with all-out motocross. It is silent and emissions-free too, but it’s also really expensive and the legalities of riding it could prove tricky. 

Stealth F-37 Electric Bike review: half downhill MTB. Half motocross machine. All fun

Stealth F-37 Electric Bike

4.0 stars
For
  • Massively powerful
  • Light and nimble
  • Ridiculous amounts of fun
Against
  • Limited places to use it
  • Styling isn’t perfect
  • It’s very expensive… and heavy

In the loop

Everything you need to know about the Stealth F-37 in short:

  • Wheelbase: 1273mm
  • Weight: 49kg
  • Max speed 38mph
  • Electric range: 40-miles (ish)
  • 180mm of front fork and rear wheel travel
  • Brakes: Formula Minicross 65 motorcycle brakes
  • 27.5" MTB wheels and tyres
  • Recharge time: 3 hours from flat to full

Styling and features

We will be the first to admit that the styling of the Stealth F-37, and all Stealth bikes for that matter, is an acquired taste. Where most of the major bicycle manufacturers aim to integrate the electrical architecture as much as possible, Stealth goes for a more brazen approach.

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The batteries are stashed inside a riveted sheet metal box that’s bolted to the frame. It has the air of an aeroplane’s black box device and doesn’t do much for aerodynamics - but that's not really the end goal here.

Bolted to this is the trellis frame structure that the seat post emanates from, which again goes heavy on the industrial chic. It’s all very angular and gives off the impression it will take a finger off if you get too close.

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The 180mm travel front forks are meaty, to say the very least, while the extra wide mountain bike bars house the shortened twist grip throttle and the motorcycle brake levers. The cockpit itself is a mash-up of motocross bike and downhill MTB machine.

The rims are unbranded, only carrying some Stealth stickers, while Schwalbe Eddy Current Addix (soft) knobbly tyres can be found at the front and rear. These are specifically designed for e-MTBs and feature an enlarged block pattern for extra grip, due to the increased weight and speeds of battery assisted bikes.

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Overall, it’s a mean looking machine, but the overarching opinion when showing it off to friends was that it looks a bit like it has been made by a skilled hobbyist, rather than a serious outfit. Not really something you want to hear after spending nearly £8,000, is it? But hey, that's just their opinion.

Charging and battery life

As we previously mentioned, this bike isn’t road legal in this country and is only really allowed to be used on private land with the owner’s consent. With that in mind, it’s highly likely you aren’t going to be charging it for the daily commute.

That’s a good thing, because the Stealth F-37 draws so much power that it’s only really good for a range of around 38-miles or so. In reality, that figure is probably a lot less, seeing as most will stick it in full power mode (rather than Eco), rip around on it and use the batteries within an hour.

The Gear LoopStealth F-37 Electric Bike review photo 1

Charging is via a regular domestic socket, with a chunky inverter that makes a lot of noise thanks to the requirement of fan cooling. This takes around three hours, which isn’t bad at all.

Stealth also offers an H-52 model, which hits a mind-boggling 50mph but also runs for a little longer thanks to an increased battery size. Cleverly, the H-52 also packs regenerative braking, which adds a little more range when coasting down hills and the like.

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There’s also a built-in display that is operated via large chunky buttons. It’s not the easiest thing to navigate, but there are a number of different power modes that help to eke out the most of battery life. It also gives a good indication of remaining charge and the amount of miles you’ve got left in the tank.

Performance in the wild

This is where things get tricky, because you’re only really supposed to use the bike on land that you either own (we hope you have a big garden) or can at least get the owner’s permission. It’s not registered for road use, so you could get in trouble using it on green lanes and bike trails, while forestry commissions, country parks and even bike parks will likely take offence to one of these hooning around.

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Now, we are sure there are many who will just take the risk. After all, it has pedals that - although largely useless for powering the bike, seeing as it weighs almost 50kg - do a good job of at least masquerading the power on tap should you need to. Simply rotate the legs and wave merrily at dog walkers… they’ll never know!

Once away from civilisation, or on some borrowed farmland (like us), the Stealth F-37 really comes alive. To say it is fun would be a massive understatement.

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The power on tap is grin-inducing and it suddenly transforms a heavy static machine into a lightweight and nimble trail beast. The best part is that it is completely silent and emits nothing from tailpipes, so you can ride pretty much guilt-free.

Both the front and rear feature huge amounts of suspension travel, but we did find the weight of the bike meant it bottomed out occasionally over jumps. This could probably be solved with proper suspension set-up and re-gassing of the shocks, but it’s something to note.

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The tyres offer a ludicrous amount of grip and we never felt it was lacking on wet, slippery and often treacherous surfaces. Even at high speeds, it gives the confidence to tip it in and twist the throttle even more.

On the subject of throttle, we would have liked to have seen a longer throttle tube used here. There’s no reason why it couldn’t be the same size as a motocross bike, rather than the stubby little thing that wouldn’t look out of place on an urban commuter. 

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Stealth has likely introduced this for a reason, perhaps so riders can tackle technical downhill sections without the risk of accidentally blipping the throttle, but we found it a bit awkward to use over longer periods.

The computer is also basic and although it does everything you want, from changing the riding modes to delivering accurate battery data, it feels like an off-the-shelf solution, rather than something that has been beautifully integrated. There's no app like with a Specialized product, for example.

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But these are minor qualms, because the bike is an absolute riot. Fun for popping wheelies, hilarious to jump over lumps and bumps and probably 100 per cent more capable than we are. 

To recap

With a clampdown on emissions and noise, electric bicycle/motorcycle crossovers like this could well be the future of fast, off-road shenanigans. It is rapid, fun, easy to lug around and opens up access to routes not previously accessible by noisy scramblers and motocross bikes. That said, it’s pricey, not road legal and it will still draw a few moans from fellow trail users, as it’s a bit of a (loveable) rogue.

Writing by Leon Poultney.