Why Rally Mexico is one of the toughest motorsport events in the world

With stages rising to heights of 2,700 metres above sea level, the cars — and the drivers — experience fierce heat and a choking lack of oxygen.

It is common to see Rally Mexico drivers as red as tomatoes at stage end, with their gasps for air a visual sign of just how physically demanding this rally is.

After the ice and snow of the Monte Carlo and Sweden WRC rounds, Rally Mexico is the first intercontinental rally of the season — bringing with it temperatures above 30 degrees celsius.

Rally Guanajuato Mexico represents the third round in this year’s World Rally Championship. But while it may be in its 16th year, it presents a unique problem for the cars that seemingly even the most experienced teams in WRC can never really anticipate.

The manufacturers each year struggle to make their cars mechanically bulletproof: the past two years have seen team Toyota Gazoo Racing WRT experience temperature-related issues with its competing car Toyota Yaris WRC, with overheating engines and brakes. However, Toyota Team Principal Tommi Makinen believes the issue has finally been resolved.

“It is always a tough event for the teams because of the altitude and the high temperatures,” Makinen said in a statement.

“We have worked very hard with the cooling package in particular. Our pre-event testing [at high altitude] in Spain last week went well and we’re feeling ready.”

Random mechanical issues abound in Rally Mexico. Last year’s WRC title runner-up, Hyundai Shell Mobis WRT lead driver Thierry Neuville, experienced devastating fuel pressure problems as early as the second day of the rally. Neuville then went on to take his thirsty Hyundai i20 WRC into a water-splash on the following stage, driving through the body of water too fast and momentarily drowning the car.

Heating issues aside, though, the difficulties of Rally Mexico not only lie in mechanical mortality and drivers’ physical fitness. The event requires experience, and competitors’ ability to adapt to changes in their car’s performance.

During Rally Mexico, WRC cars only produce about 80 percent of their maximum power output, thanks to the high altitude and low air pressure.

All this means less oxygen entering the engine, thereby reducing combustion efficiency.

The reduction in power requires drivers to think fast, altering their braking points and racing lines in a fight to keep their car moving as rapidly as possible without dropping crucial revs.

Low air pressure also has an effect on the car’s aerodynamics, reducing drag severely. This results in greater straight line speed, but also means the cars are producing far less downforce than when at sea level — a greater challenge than that experienced in other gravel rallies.

But possibly the most unique aspect of Rally Guanajuato Mexico is the spectators. Lining the streets of Guanajuato for every year’s opening night stage, local rally enthusiasts crowd every vantage point, filling grandstands and leaning from their balconies; all to get a glimpse of the lights, music, and noise of the WRC cars as they power across the tarmac in the city centre.

This city stage is one of the most fan-packed and colourful starts to a WRC event. Officials expect this year’s Rally Guanajuato Mexico to draw close to 600,000 spectators across the weekend. And the inclusion of a new big  man-made jump in the famous El Brincho stage looks set to be another crowd-pleaser — alongside the excitement of water splashes, cheering fans, and a whole lot of colour and noise.

Each year, the overall winners of the event are awarded a custom pair of handcrafted Mexican cowboy boots made by a local bootmaker. Custom boots have been worn by the likes of Sebastien Loeb, Kris Meeke, and Sebastien Ogier.