At Montgontier in Gillonnay, France, riders sign on at lunchtime for the Randonnée VTT des Marrons, an autumn mountain-bike outing connected to the village chestnut festival. It provides three self-paced VTT loops: a 20 km route suitable for families, a 35 km route with 600 m of climbing, and a 50 km route with 1,200 m of climbing. The start window is from noon to early afternoon, the finish control closes late in the afternoon, helmets are compulsory, and riders must observe the highway code.
The routes traverse quiet roads, paths, and hillside tracks around Gillonnay. The longest option includes an additional loop after the 35 km course. This event is part of a larger weekend for mountain bikers, walkers, runners, and children, featuring a cross-country race, a short trail linking local castles and chapels, and children’s races held in the castle gardens. Chestnuts are central to the day's identity: local children gather them, former farmers grill them on site, and they are offered to participants and the public.