Some people have whinged that Guggenheim director Tom Krens has demeaned the institution with the big, high-octane conundrum of a show, The Art of the Motorcycle which, with all its brand names and $.5m sponsorship from BMW, could arguably be described as a highbrow trade fair. But 400,000 people paid to see it in New York last summer, making it - according to the Economist - the third most successful, em, art exhibition ever. It opens tomorrow to a mega-celeb gathering in the Guggenheim in Bilbao.

Interestingly, the Bilbao exhibition is curated by a Irishman, Ultan Guilfoyle, who after producer/director stints in RTE and BBC, founded Planet Pictures with Bob Geldof. When he directed a South Bank Show about Frank Lloyd Wright a few years ago, he was "made an offer I couldn't refuse" by the Guggenheim in New York, and he's now head of its Film Production Unit. He's also a bit of a biker.

So why has this show been such a success? Guilfoyle: "People have an ability to relate to a design object, in a way they don't - certainly not in a mass way - with art. But also, the motorcycle happens to be one of the romantic, attractive design objects of the century - and quintessentially of the century, connected with all the great themes of popular culture, like speed, sex, death, adventure, danger. Unlike cars, which have lost their implications of freedom and escape, the motor cycle is still placed in a realm beyond the ordinary . . ."

So the central object of a grimy, petroleum-scented, worldwide subculture is now suddenly elevated into the humidity-controlled mega-gallery, the gleaming tangles of function and technology dotted around a huge 30-foot-high, figure-of-eight Scalectrixlike ramp of burnished steel. The installation was designed by Californian architect, Frank O. Gehry, who also designed the futuristic new Bilbao Guggenheim building in Bilbao; itself a shimmering city of wonky blocks covered in reflective brushed-titanium cladding.

In Bilbao, the walls will boast huge 30foot bike-relevant stills from movies - Duck Soup, Steve McQueen's bike-jump from The Great Escape, Clarke Gable on a Harley in 1949, Marilyn Brando in The Wild Ones, Easy Rider, Mickey Rourke in Rumblefish, Schwarzenegger from Terminator 2 - but not the highly paranoid Irishcinema image of a sawn-off killer-biker, The Courier.

In some spit-culture bike mags, bikes are embellished with leather lassies in hot pants, but in the Guggenheim, they are clinically presented in a pure homage to the design object itself. The rider is absent, so you have to fantasise how your body would conform to the way the design slings you forward over the petrol tank; sits you upright like a sporting vicar; or, on the American hogcruisers, leaves you just plain laid back.

Historically, the exhibition takes you from the earliest Michaux-Perreaux 19mph velocipede (1868-71), which packed a small steam engine between your cheeks; and alarming Victorian bone-shakers like Daimler's Einspur. Some are monstrous: the glowering, 60mph, tank-like Czechoslovakian Bohmerland from 1925, with its disc wheels and dual five-gallon petrol tanks on either side of the back wheel. Or the cold, monumental, single-cylinder, 11 hp, 1930s French Majestic, finished like a long radiator grille, with hub-centred steering and steel-inset instrument dials.

Everyone will recognise the big aluminium pessary of the BMW Land-Speed Record, a 493cc double overhead cam which hit 137mph on the first autobahn at Ingoldstat, and eventually 174mph in 1937 - a record which remained unbroken until 1951. Or the swaggering machismo of the Harley-Davidson Military Model U which replaced horse cavalry in WWII, with its saddle bags and Thompson sub-machine gun holster by your throttle hand. Or the insectoid design leapof the Bavarian Imme R100 (1949), its 99cc, one-cylinder, two-stroke engine nestling like an egg under the forward-arched frame.

One's mind runs down all kinds of avenues watching such a functional object change form with the Zeitgeists of the times - the old French afternoon-picnic leisure bikes, the 1950s sci-fi space-era designs, to today's bikes with their manga/graphicnovel design influences, and computer-generated hood and chrome finishes.

Being of unsound economic health, I have always flinched rather than drooled at these extreme top-end machines: obscenely customised Chevies with swooping tail fins; artefacts like the pricey Yamaha GTS1000, with its chassis reworked to accommodate a new front-end suspension system which dispensed with the telescoping forks (it didn't last long); or fat-assed models like BMW R1200 Cruiser; the high-powered Mordbidelli, or the "omega" of the show, the MV Augusta.

For Bilbao, Guilfoyle has "deepened the European and Spanish presence. Franco banned a lot of imports, and particularly in the post-War period, the Spanish quickly found a way of producing cheap, light, affordable motorcycles, which had an influence way out of proportion to its size, with their Bultacos, Montesas and Derbis." And just to keep art in the frame, there's a Vespa body-painted by Salvador Dali.

Apart from interesting essays on the Japanese bososuko (high-speed biker tribes) and Dennis Hopper's rangy prose poem, the $80 catalogue from the New York show contains some art-critical spin on the bike as icon. Get this from an otherwise excellent essay: "The motorcycle encounters the road as a writer encounters the page. There is no proper approach, no correct path, no true line . . . Lines cross and crisscross to create intersections without warning signs . . . To ride is to write and to write is to read and rewrite a text that has already been written . . . the bike is the pen, the road the rider's unfinished autobiography."

It's a classic piece of polishing the dipstick. But hell-bent on conjuring myth, the Guggenheim trace the evolution of the motorcycle's outlaw image back to the Hollister riots of 1947 in rural California. They provided the inspiration for The Wild One with Marlon Brando in 1953 and on to Russ Meyer's Motorpsycho and Hopper's classic Easy Rider - never mind Kenneth Anger's unforgettable, homoerotic Scorpio Rising, with its earnest leather-crotches chamoising down shiny chrome pipes.

Guoilfoyle: "The whole image of the outsider has a fixed reference point in the GIs who came back to California at the end of the war - to great disaffection, because people just had no idea what they'd gone through. So they reformed, in way, the dysfunctional families of the platoons, as biker gangs. The GI Bill entitled them to a free Harley-Davidson or an Indian, so they stripped them down and went out racing in the desert . . ."

Guilfoyle would probably class me as a utilitarian biker, having whined around on Honda 50s before eventually graduating to the bullet-proof Yammie RXS - a model Yamaha discontinued a few years ago, but still the best little bike on the road.

AT 100cc, it neatly undercuts the 125cc insurance premium, but with has all the vicious "poke" of anything from a 125 up. It's a courier's dream in gridlock, and is hardy, light and well-weighted enough to survive the crazy surfaces and greasy cobbles of Dublin variegated streets.

But I would hazard that the success of the Guggenheim show is the genuinely heightened experience of driving a bike, otherwise these magnificent machines would appear as baffling as Abstract Expressionism. On a bike, you're furiously focussed, eyes scanning the horizon and sideroads, working brakes against throttle, as lame-brains in cars pull out in front of you. There is a weird solidarity among bikers. And there are angels out there too who, stopped at the lights, will tell a rookie if his engine sounds like he's got a loose spark plug; or if you break down, will stop, open up a box of tools, and sort you out. And then you grit your mind and get back up on it again.

The joys of hub-centred steering: the French Majestic bike