The most successful Montesa street bike of the 1950s was the Brio 80, of which more than 12,000 were produced. The success of the Brio and the other models, led to the opening of a new, larger factory in Espluges de Llobregat. The Brio 80 and Brio 90 models contained many new advances, such as moving the carburetor behind the cylinder, and a handbrake. However, a slump in the Spanish economy had forced Permanyer to cut back on the company's racing activities. Permanyer wanted to pull out of road racing, but Bultó insisted that they stay the course. In May 1958, chief designer Bultó left, taking with him several of Montesa's vital personnel to form a competitive firm, Bultaco. Permanyer had not only lost the brilliant designer Bultó, but also his 30% share of the company.