A committed cyclist for more than twenty years, Gaël champions the bicycle as a way to decarbonise everyday life: there was a time when he rode 34 km there and back to work every day. Alongside this practical use, he rides road and mountain bike, with a soft spot for big mountain events such as l'Étape du Tour or the Grand Raid BCVS, and he has never stopped travelling by bike, as close as possible to the landscape and with the lightest possible footprint. His brief came down to a single idea: one machine for all of it. So we drew the geometry of a versatile gravel bike, as happy loaded for several days as on a sporty outing, able to carry its rider from the front door to the volcano trails.

The frame is steel, shaped by Marc in our Beaumont workshop, south of Clermont-Ferrand, from Columbus Omnicrom tubing. As on all our frames, the areas in contact with the components (the threaded bottom bracket shell, the rear dropouts, the inserts for the three bottle cages) are stainless steel, to rule out any long-term corrosion. The cable routing is internal, the rear light control integrated, and the seatpost clamps discreetly within the seatstays. A stainless steel strip on the head tube protects the paint from the rubbing of the cable housings.

For the drivetrain, Gaël chose the Campagnolo Ekar GT, the evolution of the Italian maker's single-chainring gravel groupset. In 1×13 speed, with a 40-tooth chainring and a 10-48 cassette, it offers a very wide range: enough to hold a good pace on the flat and keep something in reserve for climbing, even when loaded. Braking is handled by the hydraulic callipers from the same groupset. The same drivetrain appears on Alexandre's all-terrain, another gravel bike built for the puys of the Auvergne.

True to his wish to favour makers close to home, Gaël wanted a largely European wheelset. The Mavic A1025 rims are made in France, laced with Belgian Sapim CX-Ray spokes. At the rear, an Aivee Classic hub machined in the Vendée; at the front, a SON 28 dynamo from Schmidt, in Germany. The whole thing rolls on 650B Hutchinson Overide Hardskin tyres, 47 mm, tubeless, with tan sidewalls. A supple casing and a generous section: enough to get through almost anywhere, as Gaël soon found out on his first trails.

The bike was conceived for travel. Our racks are in-house designs. At the rear, our lightweight rack: a minimal frame of stainless steel rods that mounts with three bolts and keeps the load firmly in place, even when climbing out of the saddle; here it is paired with a Tailfin cargo cage support. At the front, a small carrier holds the handlebar bag. The bags are Gramm, made in Berlin by a small team we are fond of: a Diamond at the front, a top-tube bag and a half frame bag. Three stainless steel King Cage bottle cages complete the set-up. The same Berlin bags appear on Joël's randonneuse.

For lighting, the SON dynamo powers a Sinewave Beacon 2 headlight, whose USB port also lets you charge a device on the move, valuable on long journeys; a SON rear light brings up the rear. Gaël has already put all this to the test over two days of bikepacking, under a good few hours of rain. The same spirit of travel, dynamo included, runs through Matthieu's Gaby.

At the controls, a 70 mm Deda Mud Peak stem and a slightly flared Deda Superzero handlebar, wrapped in rubber Brooks Cambium bar tape in a warm brown that answers the saddle. The seatpost is a matching Deda Mud Peak. The headset is an orange-anodised Chris King, the first of those touches of lava that recur, in small notes, all over the bike.

The paint, by Max, tells the story of Gaël's Auvergne. Three colours blend in a gradient running from basalt grey to the orange of molten lava. Along the tubes runs the painted silhouette of the Chaîne des Puys, the volcanoes whose curves Gaël loves so much, alongside the 'AA' monogram (for Arpenteur Ardent, the Ardent Adventurer) and the number '50'. On the head tube, the Victoire sprig; on the seat tube, painted, the bike's number and the names of the craftsmen who brought it into being, Marc on the frame, Max on the paint, Antoine on assembly. The Reform Tantalus saddle, with its thermo-mouldable shell and anodised titanium rails, carries the colour play further, from blue to bronze; right down to the orange Wolf Tooth valves, everything here echoes the volcanoes.

The name says the rest. Arpenteur, the one who paces out new ground, for the love of travel and the discovery of new horizons; Ardent, like the passion that drives Gaël and like the still-living volcanoes; 50, finally, for the gift he is giving himself for his fiftieth birthday, and the fifty seasons to come. A nod, too, to Julien's arpenteur, our founder.

Gaël collected his Ardent Adventurer in Beaumont, after a bike fit that dialled in his position. He came back full of enthusiasm. His position won him over straight away, far more comfortable than on his previous road bike. Having never ridden gravel before, he had a ball: the freedom to get through almost anywhere without a second thought, more efficiency than a mountain bike, and a bike he finds playful and agile as soon as the terrain gets rough. He was even surprised by how responsive the crankset is, on a bike whose brief is not exactly sporty. His first two days of bikepacking, in the rain, did the rest: the luggage set-up was up to the task.