Apparently "The Hardest Cycle Race on Earth is not in France!" (according to Outside Magazine).
There are plenty of cycle races around the globe that bill themselves as the hardest, Le Tour de France (TdF) and Ironbike both have a good shout. But when you stack up the figures nothing quite compares to The Tour Divide.
First up, Le Tour is a Pro race, fully supported, with all the pampered luxuries that the teams can muster. It's also on European roads, riding 6.8kg carbon super-bikes.
Ironbike (MTB) is tougher. Racers camp together every night before tackling ferocious climbs and terrifyingly exposed descents, one after the next.
Tour Divide is longer than TdF at 2745 miles. It has more climbing than Ironbike - 200,000 ft/61,000m. That's not a typo! And it is entirely self-supported. Racers cannot accept any outside assistance and have to be completely self-sufficient for the entire duration, including carrying all of their necessary kit, from food, clothing, maps, and spares, to camping gear. They also have to navigate The Great Divide Mountain Bike Route (GDMBR - The longest off-pavement route in the world) all the way from Banff in Canada to Antelope Wells, New Mexico, on The US/Mexican border. Most of it on remote trails frequented by Bears and Mountain Lions, amongst other hazards like snow, altitude, and deserts. Oh, and the clock starts ticking non-stop from the second you start.
The American "Adventure Cycling Association" recommends taking 64 days to tour the route. The fastest Tour Divide racers do it in less than sixteen.
It's a bold claim from Outside Magazine but all claims are subjective, it just depends who you ask. "Shaggy" John Ross (speaking to Privateer Magazine) thinks The Colorado Trail Race is the hardest. I have several friends who are firmly in the Ironbike camp. Tour Divide is almost certainly the longest though.