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From the archives: Ariel Atom Mugen vs Radical SR3 RS vs KTM X-Bow R

Three lightweight track cars, one night in central Manchester before heading to a circuit. What’s the worst that could happen?

Midnight in Manchester, and Manchester has mostly slunk off home. It is a Monday, after all. Sockets of people still weave past, drawn to us more by a weary, p****d curiosity than the exuberance and excitement of earlier on. No one falls drunkenly into the Atom now, or sits heavily on delicate bits of the Radical. Having made it this far, I’m hopeful I’ll only get flashed by a grannie once tonight. I became detached from my comfort zone several hours ago, and haven’t seen it since. I have this in common with the cars.

Ariel Atom Mugen vs Radical SR3 RS vs KTM X-Bow R

Images: Justin Leighton

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This feature was originally published in Issue 217 of Top Gear magazine (2011)

The obvious thing to do with three intense, extreme track specials around would be to take them straight to a circuit, uncork the Stig and have done with it. Instead, what we want to do, via the medium of these ultra-light cars, is explore the concept of fun. Sounds a bit high-handed, but at Top Gear, we have a theory that these cars might just be selling themselves short by having a sphere of influence that extends no further than the pit lane.

Perhaps, we mused, by being the very essence of undiluted driving pleasure, they're a blast wherever you take them. We know that at the TG test track, each is capable of administering a supercar smackdown of heroic proportions, but they do wear tax discs after all, so let's start in the city, move to the country and wind up at a track and see where we have most fun.

And which we have the most fun in: KTM X-Bow R, Ariel Atom Mugen or Radical SR3RS. The R designation is new for the X-Bow, denoting the presence of an Audi S3-sourced engine that sits 19mm lower in the chassis and is now bolted straight to the carbon monocoque, F1-style. The Mugen is Ariel's newcomer, and the most track-focused Atom ever - it doesn't have the overwhelming focus on power of the V8, nor the distorted connection between right foot and engine of the supercharged model, just a masterfully honed, naturally aspirated four-cylinder and some handy chassis tuning.

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But it's our final contender that's making the early running with the local populace. This is not Radical's new road-going SL announced a few months ago, but a hardcore RS that's had the necessary SL bits added to make it road legal. Convincing the authorities that this can be driven on the public highway can't have been easy.

All are mid-engined, all have six-speed gearboxes, five-point harnesses and not a sniff of weather protection. Combined, they weigh just 1,920kg and develop 830bhp. One revs to well over 10,000rpm, another hits 60mph in under three seconds; all will top 150mph and are built in tiny numbers.

Manchester doesn't really care about the figures, Manchester focuses (only barely, in most cases) on the visuals. The Ariel and KTM have a strut and funk about them that lends itself to the urban environment - at heart, they're beautiful bits of industrial design as much as cars. You could, with not too much of a stretch, see them being owned by trendy types who inhabit inner-city loft apartments - maybe even mounted on an exposed brick wall as some sort of art installation. Not the Radical, though, which fights such flighty notions with every fibre of its racing being.

It looks ridiculous out here and feels ridiculous, too. The big wing seems comical, the fact you can't get the toe of a stiletto under the front splitter causes hilarity, those who ask to see the engine are amused that it involves two of us, 10 clips and disconnecting the rear lights. Hemmed in by jeers and catcalls, the Radical sits there, grumpy and ill-tempered. Later, when time is called on photography, it'll be the first to spear out of town, back alongside the ship canal, bored-out 1500cc Suzuki bike engine finally able to vocalise the higher points of its strident rev range.

Ariel Atom Mugen vs Radical SR3 RS vs KTM X-Bow R

"Pretty scaffolding," notes the evening's most eloquent passer-by, casting an eye over the Atom. It's the most at home in the Manc scene, which can't be bad for a car designed and built in Somerset. The Austrian-born KTM, wrought in carbon fibre rather than steel and with a similarly scant smattering of bodywork to cover its nether regions, has the capacity to cause shock and awe when viewed close up. The finish is beautiful, and if I had to choose one of these to have an accident in, it would be the one that sounded like teak when tapped. 

Crashing any car that fails so utterly to separate you from your surroundings (especially pointy bits of street furniture) doesn’t really bear thinking about. In fact the idea of just driving them, amongst the late-night heckling and drugged-up stares, is largely unappealing. However...

I'll take the Atom, please. Chiefly because it's got ground clearance and you can see exactly where each wheel is at all times by simply turning your head. With 270bhp produced from just 1998cc, it should idle lumpily and chunter at low revs, but then you remember that Honda built it and instead marvel at its tractability and pure throttle response. Tiny and agile, it zips and zaps around these streets, whipcracks out of junctions, and laps up the whole experience. Ditto the fluorescent orange KTM, but with ease turned up to 11 by dint of the VW turbo engine (low noise, gentle pedal response, general nonchalance, etc). Fear is also ramped up by having all that carbon strapped within easy reach of speed bumps and kerbstones.

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I dread the Radical, because I know that if I stall I'm going to struggle to remember the sequence to get it started again. It's one of the reasons why I haven't been worried about anyone stealing any of the cars (OK, that's not quite true, because half a dozen blokes could probably make off with the Atom, just by manhandling it), but actually getting in and starting them up? Not a chance, given the complexity of button pushes, switch flicks, pedal presses and waving of immobilisers required.

Naturally, I stall the Radical. Outside a busy city-centre bar. I swear at the SR3 RS, which responds by firing immediately, clunking into gear, dialling up a shrill 4,000rpm and making good its escape. It's not a natural city car...

Ariel Atom Mugen vs Radical SR3 RS vs KTM X-Bow R

A few hours later, I'm up to my neck in the Radical - this isn't a figure of speech but a comment on the driving position (you sit shoulder-deep in the Ariel and are exposed above the nipples in the KTM). We're on the M56, it's morning rush hour and Manchester, seen in the tiny mirrors, is vibrating busily. Did we have fun last night? Well, it's not a night I'm going to forget in a hurry and a tinge of post-stress relief always gives events a brighter sheen. The KTM and especially the Atom were perky and fearless, but the Radical was too emotionally tied to the track. It felt homesick.

But it's happier now, with hints of Snowdonia ahead, and, despite my distorted facial features, so am I. You see, at 30mph, the lack of a windscreen is an engaging novelty. At 80mph, it's frightening. A bumblebee to the schnozzle is going to more than sting when the wind alone causes problems, especially in the KTM, which has your head weaving around in the airflow like one of those nodding dogs. The Atom, in which you feel most exposed, is actually the calmest: you hunker down behind the aero screens like a fighter pilot lining up the enemy, and the cockpit itself is a joy, as much for the ergonomics of having everything perfectly organised within finger's reach as for the view down the empty footwell. It's sort of addictive watching the steering working, seeing the wheels bob around. Which they do. A lot.

The Atom is light - a third of a tonne lighter than the KTM - and it's also stiffly suspended, which will be great when we get to Anglesey, but out here, homing in on some great mountain roads, the suspension doesn't get a chance to fully absorb a bump before the shock is transmitted to the whole lightweight chassis. This causes it to buck around, and – with little weight on the nose and track tyres struggling on damp tarmac – the experience is akin to grabbing a tiger by the tail.

Ariel Atom Mugen vs Radical SR3 RS vs KTM X-Bow R

But you don't fight the Atom, as it's so much fun to work with, so instead of letting fear and physics take hold, you slow down and enjoy the steering feel and dazzling engine. We could have softened the set-up for road use, but we don't know what we're doing and would probably only have made a mess of it.

And besides, the Atom is compliant compared with the Radical. The SR3's party trick is sniffing out cambers, and from the way the steering tugged in my hands, I don't think it missed a single one all day. This dartiness meant you rarely had the opportunity to properly get on the power and give it what for - but when you did, it wasn't the engine that grabbed you, but the sequential paddleshift pneumatic gearbox. Shift time 0.02 seconds. Hell yeah. Need to be going hard to keep it smooth, but wow, just wow.

A 20-mile strop on these roads is a workout. Pummelled by air, tarmac and noise, you buzz and tingle with energy for minutes after you stop; something best savoured by sitting back, resting your head, enjoying the sudden silence and stillness, and waiting until your heart rate has subsided. This, I have to make clear, is a key part of the experience.

Unless you've been driving the KTM. It's much calmer than the British offerings - you feel the extra weight pushing down and dulling responses from engine and suspension. Not the steering, though, which although it has little of the Atom's fizzing feel, is exceptionally sharp. Too sharp, really, darting into corners at the merest suggestion of pressure from your hands. The grip is outstanding too, and for speed alone on these roads, the KTM is king. Forget engine noise, because next to its rivals there's none, but the turbocharger doesn't half administer a sizeable kick.

But there's a gulf between the smooth ride and power delivery and the fact you're sat in a bonkers carbon bathtub watching suspension arms pumping and scenery being reeled in at a surreal rate. The X-Bow doesn't act like a lightweight - you get the feeling that removing the windscreen from a TT RS roadster would result in a broadly similar experience.

OK, so this R version is undoubtedly snappier than the standard car, and you still get the widescreen scenery view and smell of heather, but even with nothing between you and the landscape but a pair of shades, connection feels diminished.

It's raining on Anglesey the next day. In fact, it's poured down the whole way over, which served to prove that the Atom driver gets wettest and there's no such thing as a quick hotel getaway when you have to towel your plastic seat dry and strap on a five-point harness.

But we're now at a racetrack. Home territory. And by lunchtime it's dry, there's heat in tyres and brakes and no more excuses. The KTM is devastatingly effective. It's short, wide, grips mighty hard at both ends, and when it does break loose it's surprisingly friendly. The Atom, as it has been all the way through this test, is the X-Bow's polar opposite. I'm not sure it's any quicker around here, but it has a totally different approach to corners. The KTM is conventional: you brake, turn in and power out. In the Ariel, you have options to change direction throughout the corner, so you play with throttle and steering and the nose and tail move around accordingly.

Ariel Atom Mugen Top Gear

This sums up the difference between them. The KTM is a numbers car - stupendously rapid, smooth and easy, but the edgier Atom makes it feel stodgy. And the Radical? I'll be honest: I never got it until that afternoon, having found it hard work. But at Anglesey, it came alive in my hands as I learned about this great thing called downforce: 750kg of it at 125mph, to be precise - enough, in that phrase beloved of the F1 fraternity, for it to drive upside down in a tunnel.

Above 80mph, you feel this force as the steering weights up, and the damn thing becomes unstickable. It's hilarious and addictive, and I'm sure I never got anywhere near the limit. Only 15 per cent of Radicals are used on roads; the other 85 per cent stick purely to circuit work. And that's what the road/track balance feels like when you're driving it.

The other two get closer to 50:50: the KTM for its ease of use, the Atom for its engaging character and intimacy. Need you ask which is our winner? It's the one that's been nothing but fun along every part of the journey west from Manchester, a Braille fingertip of a car that feels everything and communicates everything. Ariel hasn't built a better Atom than the Mugen, and if there's a way of having more fun in a car, we've yet to find it. So go on, get some adventure in your life, buy a lightweight. Crap tagline, great philosophy.

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