“...a region which...possesses no possibility of conveyance by any mechanical means.” was included in Robert Marhsall's definition of wilderness in his 1930 essay, The Problem of the Wilderness. The challenge is what does he mean by mechanical? The words bicycle, non living power source, moving parts don't occur in his essay, so we need to dig a little deeper to understand what he meant by wilderness and mechanical.
"And so the path of empire proceeded to substitute for the undisturbed seclusion of nature the conquering accomplishments of man. Highways wound up valleys which had known only the footsteps of the wild animals; neatly planted gardens and orchards replaced the tangled confusion of the primeval forest; factories belched up great clouds of smoke where for centuries trees had transpired toward the sky, and the ground-cover of fresh sorrel and twinflower was transformed to asphalt spotted with chewing-gum, coal dust and gasoline."
I don't think a bike on the Gallatin Crest qualifies as the path of empire.
"This involves something more than pure air and quiet, which are attainable in almost any rural situation. But toting a fifty-pound pack over an abominable trail, snowshoeing across a blizzard-swept plateau or scaling some jagged pinnacle which juts far above timber all develop a body distinguished by a soundness, stamina, and élan unknown amid normal surroundings."
Or perhaps riding a bike at treeline through a thunderstorm, or bikepacking over a trail littered with cobbles.
"In a civilization which requires most lives to be passed amid inordinate dissonance, pressure and intrusion, the chance of retiring now and then to quietude and privacy of sylvan haunts becomes for some people a psychic necessity."
Whether someone is one a bike, a horse, a canoe, or on foot the need to escape is the same.
"Adventure, whether physical or mental, implies breaking into unpenetrated ground, venturing beyond the boundary of normal aptitude, extending oneself to the limit of capacity, courageously facing peril. Life without the chance for such exertions would be for many persons a dreary game, scarcely bearable in its horrible banality."
When we talk about mountain biking in the wilds of Montana, it is the adventure we are seeking, exploration and adventure on primitive unimproved trails.. An escape from the ordinary and routine.
"This equivalent may be realized if we make available to every one the harmless excitement of the wilderness. Bertrand Russel has skillfully a,plied this idea in his essay on 'Machines and the Emotions.' He expresses the significant conclusion that 'Many men would cease to desire war if they had the opportunities to risk their lives in Alpine Climbing.'"
Or mountain biking.
"It is upmost importance to concede the right of happiness also to people who find their delight in unaccustomed ways."
You may hike, maybe ride a horse. I ride a bike. None are wrong, just different paths of discovery.
"Far more can enjoy the woods by automobile. Far more would prefer to spend vacations in luxurious summer hotels set on well groomed lawns than in leaky, fly infested shelters bundled away in the bush."
"But the automobilists argue that a wilderness domain precludes the huge majority of recreation seekers from deriving any amusement whatever from it."
Mountain bikers aren't asking for roads or even trail improvements. We want the same experience as other quiet non motorized uses. We want wilderness in its raw primal form.
Having read the essay, it is clear to me that mountain bikes epitomize the wilderness ethic and spirit of adventure espoused by Mr. Marshall. A valid method to escape from the asphalt and noise of modern life. Bikes are not the mechanical conveyance he had in mind. It was cars, trains, and motor boats.