On a visit to the Pinarello store in London this week, where he was presented with a Giro celebratory pink bike, Geoghegan Hart revealed the terms of the bet he and his younger brother had made.
The British rider passed the Australian on the final stage time trial to claim his maiden Grand Tour victory.
"Have you heard about the bet I made with my other brother? It’s cost me a car, winning the Giro," he said.
"Stage 15 I bet him that 'there’s no chance I’m going to win this, don’t be ridiculous, I’ll buy you a new car if I win'. And yeah."
The 25-year-old Londoner was sitting fourth overall after winning Stage 15 of the Giro, but he was still nearly three minutes off the overall lead of the race. First and second-placed riders Joao Almeida (Deceuninck-QuickStep) and Wilco Kelderman (Sunweb) slipped dramatically in the subsequent stages as Geoghegan Hart and Jai Hindley (Sunweb) went on the offensive.
Fulfilling the bet, Geoghegan Hart bought the car, posting a phot to Instagram of him and his brother sitting on it.
Geoghegan Hart and INEOS Grenadiers took home nearly $AU700,000 for winning the Giro d'Italia overall, along with seven stage wins for the squad all up. The majority of a high-end professional cyclist's money comes from contracts and endorsement deals, and with Geoghegan Hart looking like he'll be a Grand Tour star for some time, a few more cars may be on the way.