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 MM - 170 30 B
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Photo ou archives : D. Ganneau

Capacity : 170
Model : 30 B
Production : 1930 -
Category : (R) Street Bike


175cc Tipo 30 B -1930

The end of a trend

In 1924, two young men, Mario Mazzetti (who had come from GD) and Alfredo Morini (who would later on found his own marque), met Giuseppe Massi-Mazzi and Angelo Mattei in Bologna. Inevitably, perhaps, the make of motorcycle that resulted from their meeting was called "MM," for there was not a shortage of that letter in their initials. Nor was the company name thrown out of kilter by the retirement of Massi-Mazzi and Mattei in 1927.

Popular Layout

The first machine launched by MM was closely related to the GD for which Mazzetti had been partially responsible a little while earlier. Its layout, with a horizontal two stroke single-cylinder engine, was one that was universally popular among makers of lightweights in the 1920s and was used - among others - by Evans in the US and Cockerell in Germany.

Italian Champions

MM followed this trend for a relatively long time. Riding an MM 125, Tigli was Italian Champion in 1926-27, and Mariani succeeded him in 1928, again on an MM 125. Shown here is a later 175cc version whose sport record was relatively meager; even adding a piston-type supercharger failed to improve its performance sufficiently. The return to sport success for MM only came when it switched to four-stroke engines. After Morini left the company in 1937 after falling out with its new owners, his influence on MM design rapidly faded; Allied bombing of the works in 1943 didn't help, either. The company was finally closed in 1958, having made 8030 bikes.


Engine: 172cc (56x70mm) air-cooled single cylinder

Power Rating: 12 hp @ 6500 rpm

Valves: two-stroke; ports controlled by piston skirt

Fuel System: carburetor

Transmission: 2-speed, chain final drive

Suspension: girder forks (front); rigid (rear)

Brakes: drum (front & rear)

Wheels: 3.00x19 inch wire (front & rear)

Weight: 176 lb

Maximum Speed: 78 mph


The little horizontal (wo-stroke single was a popular design in the 1920s, but was becoming outmoded by 1930 when this little 175cc single was built.

Le fichier Moto Passion réalisé par François-Marie Dumas réunit près de deux mille photos accompagnées d'un historique très complet des machines présentées.
Il sera progressivement mis à jour ici et toute information complémentaire est la bienvenue sur info@moto-collection.org.

Cette documentation unique, qui constitue sans doute l'encyclopédie la plus exhaustive jamais écrite sur l'histoire de la moto, a été réalisée avec l'assistance de nombreux spécialistes dont principalement Didier Ganneau, Christophe Gaime, Mick Woollett, Jean Goyard, Bernard Salvat, Christian Rey, Yves Campion, Helmut Krackowizer, Michael Dregni, Michel Montange, etc. que je remercie ici.

Disponible sur demande :
- Les fiches originales sur papier
- Les photos et archives signées de mon nom en haute définition ou les documents originaux.
Me contacter sur info@moto-collection.org pour les conditions et droits d'utilisation.