Days earlier the group, along with almost 100 other riders, were in San Diego, the start point of the Baja Divide. It’s a 1,700 mile long route along the Baja California Coast, mostly on unpaved dirt tracks winding through valleys and mountain ranges, that these people tackle sometimes with very limited provisions along the way—all by bicycle. The route was originally mapped out by two experienced cycle tourists: it’s a rigorous test of endurance, where even the most experienced mountain bikers push their bikes uphill.

Now the Baja Divide has become an annual tour where a group of wiley cyclists appear to spin their way up hills and make lunchtime stops in the company of bearded lizards in abandoned Spanish Missions. They ride on mountain bikes fitted with bags carrying everything they’ll need along the way: tents, sleeping bags, slingshots and maybe an extra pair of underwear. Strapped with gear and equipped with fat tires, their bicycles look like vehicles lifted off the set of Mad Max—and so do some of the riders. The crowd of Baja Dividers is a mixed bag—there’s more denim than lycra in this peloton, and a general favor of steel over carbon.

We spoke with Spencer Harding, photographer and professional bicycle tour leader that took some spectacular shots of the 2017 Baja Divide. He practically spends half of his life in the saddle, and his photos document the pedal-powered adventures he goes on.