The watch will be auctioned at September’s Luxury Edit sale in Paris, and carries an estimate of €200,000 to €400,000 (£170k-£340k). Only two others were made and both are owned by Cartier.
“There is no doubt that this Cheich watch, the only one awarded and the only one to come from private hands, is one of the most important Cartier wristwatches ever made,” said Colson.
Rahier won his first Belgian junior motocross championship aged 16, became world motocross champion three times, riding a 125cc Suzuki, and was awarded the National Trophy of Sporting Merit, Belgium’s highest sporting accolade.
After almost losing his hand in 1982 accident, the dogged Rahier, nicknamed the “little man with the giant reputation,” returned to racing and entered his first Paris-Dakar in 1983, retiring from the lead with a crankcase problem.
His triumph in 1984 came at the expense of Hubert Auriol who had won the Dakar motorcycle category twice and took eight stage victories in ’84. Rahier only won three stages, but finished first thanks to his consistent pace and no lack of determination.
That extended to ditching most of the ten litres of water that riders were obliged to carry in case they got lost. Years ago, Rahier told Mat Oxley that he poured it away when out of sight of starting officials to save a few kilos.
He appeared to need every advantage in 1985 when a collision with a truck on the first stage put him 30th and well behind the leaders. Then his team-mates dropped out, and he lost a further two hours with a flat tyre.
Down and apparently out, Rahier launched a sensational comeback through some of the Dakar’s toughest-ever terrain. Chasing the frontrunning Gilles Picard (riding a Ligier-Cagiva alongside new team-mate Auriol), the Belgian rode with the leaders, despite lacking support from his absent team-mates.
In a Ténéré desert sandstorm where the rescue helicopter was in constant demand, Rahier pulled the deficit back to less than an hour and continued closing on Picard, who was being aided by the experienced Auriol. But time was running out and it looked as if it would all be in vain until mechanical issues hit both Picard and Auriol.
Once again, Rahier was the rider spraying the champagne on Dakar beach after what he described as “the toughest race of my life”.
Nobody else ever won the Cartier Challenge, which ended in 1986 after Dakar founder Sabine’s death in a helicopter crash. Rahier went on to race in the 1987 Le Mans 24 Hours and retired from racing in 2000.
His watch is currently on view at Sotheby’s Monaco gallery until July 17 and will then be exhibited in Paris until its auction.