COLOGNE, June 26 (Reuters) - More than a third of clients who tried BMW’s DriveNow car-sharing business sold their car and only 20 percent were determined to hold on to their privately owned vehicles, the head of the scheme said on Friday.

Sebastian Hofelich, who became chief executive of DriveNow in April, said the short-term rental service was helping to displace privately owned vehicles but the service was not cannibalising the existing BMW customer base.

“As a rule the DriveNow car did not replace a BMW. The typical BMW driver is aged 50 or older, while our customers have an average age of 32,” Hofelich told Reuters on the sidelines of an automotive conference in Cologne, Germany.

BMW and car rental company Sixt founded DriveNow in 2011, among the early movers as established carmakers seek ways to stay relevant for a generation of drivers that increasingly prefers the convenience of car sharing rather than owning a vehicle.

About 38 percent of DriveNow clients have sold their private cars, Hofelich said. Those DriveNow clients tended to use their private vehicles only at weekends and were questioning whether it was worth owning a car full time.

DriveNow’s survey of its customers revealed that only 20 percent of the car-sharing scheme’s clients are determined to keep their private vehicles.

“The rest can be persuaded to stop using their private vehicles if we meet their mobility needs,” Hofelich said.

Earlier this week BMW’s Mini brand said it was launching a scheme that gives buyers a way to offer their private vehicles for short-term rental to third-party users, much in the same way that owners of apartments offer their flats for rent via Airbnb.

BMW has launched DriveNow in Berlin, Duesseldorf, Hamburg, Munich, Vienna, San Francisco and parts of London with a model that allows users to make one-way journeys without having to return the car to the point of departure.

The scheme now has more than 450,000 users and makes a profit. (Reporting by Edward Taylor; Editing by David Goodman)