Tailwind while ‘Everesting’ does little to help cyclists

Everyone who cycles knows the tribulations of a headwind and the joys of a tailwind. But according to a new study, in one tricky type of cycling, the tailwind is of little use.

One of the more coveted challenges in the world of cycling is ‘Everesting’ – cycling up and down a hill until you have climbed the equivalent of 8,848 metres, or the height of Mount Everest.

The record for the fastest Everesting is currently held by Ronan McLaughlin.

But McLaughlin had a strong tailwind of 20 km/hr on his uphill climbs when he set the 2021 record. Would that have helped reach his under-7 hour time?

Not really, according to a new paper published in the American Journal of Physics.

The study was done by Professor Martin Bier, a physicist at East Carolina University, USA.

“In running, the motion of the legs is repeatedly accelerated and decelerated, and the runner’s centre of mass moves up and down,” says Bier.

“Cycling uses ‘rolling,’ which is much smoother and faster, and more efficient — all of the work is purely against gravity and friction.”

Air resistance is the primary thing that limits cycling speed. But air resistance and speed don’t have a linear relationship – in fact, force of air friction is linked to the square of speed.

That means that if a cyclist wants to go twice as fast, they need to apply 4 times the force – and if they want to triple their speed, they need 9 times the force.

But when cycling up a hill, air resistance isn’t as big a deal – the cyclist is going so slow that it makes less of a difference. Instead, gravity plays the biggest role.

“When you’re riding up a hill and fighting gravity, doubling your power input means doubling your speed. In bike races, attacks occur on climbs because it’s where your extra effort gets you a bigger gap,” says Bier.

“Naively, you may think that a strong tailwind can compensate for an uphill slope,” says Bier.

“You then ride up the hill as if it’s a flat road, and on the way down the headwind and downward slope balance out and again give you the feel of a flat road. But it doesn’t work — the square I mentioned earlier wreaks havoc!”

Bier’s calculations suggested that the tailwind might make a small difference on the climb, but the headwind makes a big difference on the descent.

“Air resistance goes with the square of the speed, which leads to the headwind on the descent and causes a big reduction in speed,” Bier said. “The wind boost on the ascent is cancelled out.”

So, what are the best conditions to Everest in?

“There are no easy tricks,” says Bier.

“If you want to be a better Everester, you need to lose weight and generate more watts (exercise). This is what matters — there’s no way around it.”