We're rolling along in the opening 7km of the neutral zone of stage three of the Tour of Britain from Jedburgh to Dumfries, but already riders are pulling up en masse at the side of the road to empty their bladders.
"They perhaps drink a bit too much coffee before we start," he says in dulcet Spanish tones. "It's always best to go now before the racing starts properly."
It's certainly a side of cycling the average fan doesn't see from television's helicopter coverage. Which is exactly what Livingston-based Endura Racing promised when they invited me to ride with directeur sportif Sans Vega in their team car.
Four hours in a pro cycling team car is not for the faint of heart, or stomach. With every twist of the road, often taken at breakneck speed, my breakfast swirls ferociously.
As the convoy winds through the Scottish Borders, every so often a vehicle breaks away, horn blaring, haring up narrow lanes in search of a rider with a puncture or mechanical woes.
Sans Vega has worked on 10 Tours de France, four Giros d'Italia, six Vueltas a Espana and five world championships as a soigneur (cycling-speak for all-round dogsbody/carer) or directeur sportif.
Charismatic, with a dry sense of humour, he regales me – and Miguel, the mechanic in the back – with tales of past adventures.
Sans Vega is master strategist, in a role requiring mathematical genius meteorological prowess and the reflexes of a rally driver. He has an arsenal of maps, marked out with that day's stage, potential danger points and predicted wind directions as the road weaves south-west to Dumfries.
Word comes of a breakaway up the road. Sans Vega scans the general classification times taped to the dashboard, quickly calculating if the breakaway will have any bearing on the overall standings or jerseys.
There's a tap on the window. It's Endura rider Russell Downing. "Everything okay?" asks Sans Vega with concern. "I'm heading to see the doc," says Downing. "Got a bit of a sore head."
"Have a Coke," suggests Sans Vega, gesturing to the cans in the back. "Sometimes it helps." "Nah, just need some paracetamol," says Downing, and cycles off.
Having left Jedburgh in sunshine, suddenly heavy showers move in.
There's a crackle on the radio. "Endura to the peloton," comes the call. Horn blaring, Sans Vega pulls out and accelerates down the road. Miguel is poised in the back, ready to leap out if required.
There's no drama. They are simply wet and thirsty. Paul Voss loads up with water bottles as Zak Dempster and Ian Bibby collect rain jackets to distribute among the team.
Ahead, barely visible through rain and low cloud, the peloton are preparing for the first category climb of Turner Cleugh Law, moving as one in a bobbing motion reminiscent of salmon battling upstream.
It feels like being on safari and marvelling at wild beasts close up as they roam free in their natural habitat.
There's a flash of the rainbow bands worn by Mark Cavendish, the distinctive lime-green jersey of two-times Giro d'Italia winner Ivan Basso, and the vivid tangerine blur of Samuel Sanchez and his Euskaltel-Euskadi team.
In the Endura team car, however, all thoughts centre on one man: team leader Jonathan Tiernan-Locke.
The 27-year-old rider was one of the standout performances of the 2011 Tour of Britain, winning the king of the mountains title and finishing fifth overall. It's hoped he can prove the dark horse in the general classification this year.
No British rider has won their home tour in almost two decades, and Endura is determined to change that.
While his team-mates are charged with keeping Tiernan-Locke safe, this stage is likely to end in a sprint finish, meaning the best chances of an Endura victory will fall to Downing.
With 60km to go we pass through the feed zone. The soigneurs hand back four out of six bags still filled with food. "No-one is hungry?" says Sans Vega.
Downing is back at the window. "Caffeine," he says as Sans Vega hands over energy gels.
As Dumfries draws closer, thoughts turn to the final sprint. Cavendish of rival team Sky is the favourite.
"Cavendish has lost the first two stages, his confidence will be low," says Sans Vega. "Then again, it will make him hungry."
We drive in silence, ears strained for news on the radio. The tension builds, then, finally: "Cavendish wins." Downing is sixth.
Is Sans Vega disappointed? He smiles and shakes his head: "That's bike racing. Tomorrow is another day."
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