BERN, Switzerland (AP) _ Swiss soldiers are to get new bicycles before the year 2000 to replace the 80,000 vintage bone-breakers still in use, the Defense Ministry said Wednesday.

A spokesman of the ministry's armament services group said several manufacturers have been invited to submit studies for prototypes.

Spokesman Hugo Wermelinger said it had become increasingly difficult and expensive to get spare parts for the bikes now in use, which date to a 1905 version.

The black, single-speed army bicycles have become famous for their sturdiness, although their weight - 50 pounds - does not make them very easy to handle.

They have been much in demand even among civilians. The last were delivered to the army a few years ago, at a price of 1,400 Swiss francs ($58) each.

Wermelinger said the ministry plans a gradual substitution of the old models during the 1990s. He said manufacturers were told to develop lighter models and to keep in mind that the average height of soldiers had increased substantially since 1905.