32.1 kilometers, 1:46 to claw back: Here's the maths Primož Roglic needs to know to overhaul Mas at the Vuelta

The 32.1-kilometer flat time trial on stage 18 of the Vuelta a España is the day Primož Roglič has been waiting for, and Enric Mas has been dreading. Roglič trails Mas by 1:46 in the general classification, and the race against the clock from El Puerto de Santa María to Jerez de la Frontera is a time trial specialists dream. I.e. pan flat, with only a few sections where the pace drops. It represents Roglič's best, and perhaps only, chance of overturning the deficit to Mas. But can 32 kilometers of flat Andalusian road actually erase a gap that large? The numbers from their past encounters suggest it can.

The most relevant historical comparison comes from the 2021 Vuelta a España. Roglič clocked a time of 44:02 to beat Magnus Cort by 14 seconds in the 33.8km time trial in Galicia, securing a third consecutive red jersey in the process.

Mas finished 9th, with a time gap of 124 seconds, meaning Roglič gained over two minutes on the Spaniard in a single day. Mas was Roglič's two minute man on that day, and the Slovenian caught and overtook him. Images that will be seared into in the race leader's brain as he lines up for the TT on stage 18.

It is worth noting that Mas may have been riding conservatively that day, since Mas had a 2:10 lead over third-place Haig coming into the final time trial and his podium spot was safe. The 2021 result was not an outlier. In the 2020 Vuelta stage 13 time trial (33.7km), Mas had what he described as "a disaster" of a day and could only manage 16th place, bettered by all four riders who started above him in the overall standings: Primož Roglič, Richard Carapaz, Hugh Carthy, and Dan Martin.

A flat time trial of almost the exact same length (25.8km) during the 2023 Vuelta saw Enric Mas and Mikel Landa as "the serious contenders to lose more than 1:30." That was on a shorter course. Over 32 kilometers the expected gap could be well over 2 minutes.

On paper, the pattern is clear: in flat time trials of 25 to 34 kilometers, Roglič has consistently been 1:30 to 2:00 or more faster than Mas. A 1:46 deficit is within that range.

The Spaniard is fully aware of the threat. After extending his lead by 27 seconds on Calar Alto in stage 12, Mas told media: "Those 27 seconds are important for next week, I am happy about that." He then offered a revealing acknowledgment of Roglič's superiority against the clock. "We have to be aware that Primoz Roglic is an Olympic champion and has an impressive time," Mas said, according to AM850.

Spanish national coach Alejandro Valverde also identified Roglič and the time trial as the biggest threat to Mas's red jersey: "We know who Roglic is," said Valverde after stage 11. "It’s clear that he may not be the same Roglic he used to be, but he still fights for everything, and we still have a stage ahead of us where he can make up time—namely, the time trial in the third week."

From the Red Bull camp, there is a similar recognition that the equation is finely balanced. "I'm not going say a clear number on that," Vanthourenhout told Cyclingnews when asked how much time he thought Roglič could lose before it became impossible to beat Mas. "But let's say that from now on, every time we lose, it's not the best."

Red Bull team manager Patxi Vila is confident the time trial suits Roglič and believes the Slovenian can still win this Vuelta. The question is whether stage 18 will deliver the decisive blow, or merely narrow the gap.

The course looks ideal for Roglič. With just 169 meters of elevation gain over 32.1 kilometers, it is a pure test of raw power on flat roads. Wind could be as important as the clock along the coast near Cádiz, but unpredictable gusts would likely hurt the slight lighter Mas (61kg) a bit more than Roglič.

Primož Roglič is a four-time Vuelta a España champion (2019, 2020, 2021, 2024) and the 2021 Olympic time trial gold medalist, but this is a very different version of the Slovenian. He was hit by a car during training before the Vuelta and lost five weeks of preparation.

Unlike the Roglič of old, He has not launched a single real attack in 12 stages of this Vuelta. He is 36 years old. And even if he closes the gap in Jerez, the race does not end there.

Stage 20 from La Calahorra to Collado del Alguacil has more than 5,000 metres of climbing and a monster 8.3km final ascent averaging 9.8 per cent. There is also a summit finish on stage 19 to Peñas Blancas. Those are stages tailor-made for Mas to fight back in the mountains where he is strongest.

The pure maths says Roglič can close a 1:46 gap against Mas in a flat time trial of this length. The precedent says he has done it before. But the 2026 version of Roglič, rebuilding fitness after a car accident at 36, is asking his body to do something it might no longer be able to do.

Stage 18 will reveal much at the 2026 Vuelta a España, but whether it provides a decisive GC move or just a nerve-racking day for Enric Mas, remains to be seen.