Since the emergence of non-tilting 3-wheelers like the bizarre snowmobile-for-the-road Can-Am Spyder, and the abundance of attention they've received, this new class of novelty multi-wheelers seems to be gathering steam. The latest we've run across, thanks to a Gizmag reader suggestion, is the GG Quadster. This Swiss creation takes the 167-horsepower motor and electrics from a BMW K1200 sportsbike and puts it in a 4-wheeled chassis with sticky sports tyres and more machined billet aluminium than comes out of OCC in a whole week. At US$65,000, or around US$40k more than the Can-Am Spyder, you'll rarely see one on the road. But if you do, and there's a really tall black guy riding it, you might want to catch him for an autograph.

GG stands for Gruter und Gut, the fabrication shop that brought us the GG quad a few years back. That odd-looking contraption used the 100-horsepower BMW boxer twin motor and stuck it in a similar, F1-style race car chassis, and it proved popular enough for GG to move on and bring us the Quadster - a similar machine, but with a generous dollop of extra power thanks to its sportier inline 4 cylinder K1200 motor.

That motor uses its normal BMW gearbox, with similar gearing, but with the addition of a reverse gear, which can be engaged by flicking a safety switch and then pressing firmly on the rear brake pedal. A handy touch, since vehicles of this kind are almost as hard to push around as a small car.

Speaking of small cars, the Quadster's road footprint is actually slightly longer AND wider than that of a Smart car. But then, Smart cars aren't designed to pull over 1G of sideways acceleration in the corners, nor do they have to deal with a high-revving sportsbike engine. Well, most of the time, anyway.

Each of the Quadster's 4 wheels is shod with wide, sticky Dunlop Sportmaxx tyres, and suspended with a quality Wilbers shock, adjustable for preload and rebound. The brakes are reportedly absolutely massive, with the front lever operating a set of four-piston stoppers on the 270mm discs at the front, and the foot lever operating another two calipers at the front as well as a 30% load through two more calipers at the rear wheels. Stomp to stop, then.

The gearing is tall, as befits its 180mph donor sportsbike, but many testers have found it too tall for a heavier, street four wheeler like this one, which is only rated up to 130mph anyway. Once the clutch hooks up and the revs start building, though, hang on! The Quadster is said to be able to rocket to 60mph in 3.5 seconds.

And here we get to the handling. When Gizmag editor Noel McKeegan rode the Can-Am Spyder, he gave it a generally positive review. I'm not sure I'd be so generous. When you're presented with a machine that has a high-revving performance engine and eyeball-popping brakes, you expect it to be a demon in the corners too.

But I found that the Spyder was a real handful in the corners - and I'd go so far as to assume that the Quadster would have a very similar feel. Non-tilting multi-wheel motorcycles have the uncomfortable effect of wanting to throw the rider way out to the outside of the corner. In order to get them around corners at the sorts of speeds that you'd use on a sportsbike, you've got to lunge for the inside of the corner before you make your steering input, which is to pull the inside bar towards you - as opposed to the push you'd normally use to countersteer a bike.

So your outside arm, which has to operate the throttle, if it's a left-hander - can end up quite far away from you, and the inside wheel can start to lift off the ground. It's a very physical style of vehicle to ride, and the dynamics don't make it easy to relax and flow fast through a set of corners. It's a real core-muscle workout, throwing these things about - imagine trying to hook a regular quadbike into a bend at 70mph. Exhilarating, certainly, but a fair fitness challenge if you want to keep up with your buddy who's strapped into the sports seats of his Lotus Elise through the corners.

It would certainly be interesting to see how these machines perform on a racetrack - putting them up against cars and motorcycles to see how they go in terms of lap times, rider safety and fun factor.

Dubious cornering performance aside, the Quadster avoids one serious annoyance a petrolhead would find with the Spyder - it doesn't have a stability control system, so you're free to spin the rear wheels up and get sideways if you're feeling feisty and you're able to break the grip of those two massive rear hoops.

Because there's still so few of these types of vehicles on the road, they're still a guaranteed head-turner. The Quadster can be licensed in Germany as a 4-wheeled motorbike, and it seems registration is somehow possible in America, too.

At US$65,000, the GG Quadster is horrifically expensive if you compare it to a 3.5-second motorcycle, or exceptionally cheap if you compare it to a 3.5-second car. It's just about right if you compare it to high-end custom motorcycles and take in the sheer mass of billet you're getting for your dollar. The list of available options is very impressive for such an odd vehicle, with enormous panniers, alarms, heated grips, limited slip diffs, intercoms, navigation systems and the like all catered for. But you'll want deep pockets to pay for them.

One set of deep pockets that have already been plundered for a GG Quadster belong to the trousers of basketball god and general sports nut Michael Jordan, who already owns a pair of the older GG Quads and has stumped up for the big brother bike.

If Michael ever tires of the Quadster's 167 horses, it's comforting to know that there's a similar machine available that looks a lot nastier and packs about 3 times the power due to its supercharged BMW V12 - that would be French custom cycle shop Lazareth's US$284,000, 500hp Wazuma. Scary.