1956 Ducati 175 Twin
With Phil Aynsley
The 1956 175 Twin has the honour of being Ducati’s first multi-cylinder model and was first seen at that year’s Milan Show (where it was christened with the nickname “Il Testone – Bighead”.
The 180º DOHC design was not a Desmo but was a twin over-head cam driven by spur gears from a jack-shaft between the cylinders. Both the fly-wheels and big-end were machined from steel billet and all gears were drilled to reduce weight.
The 175 Twin had a single competitive outing – in the 1957 Giro Motogiro d’Italia resulting in a DNF for rider Leopoldo Tartarini.
Ing. Fabio Taglioni used the basic design (although now with Desmo heads), in his later 125, 250 and 350 GP parallel twins.
The 175’s dry clutch was replaced by a wet clutch on the later bikes. A design feature that did carry over was the use of expensive Hirth couplings to join the separate flywheel assemblies.
With development resources being concentrated on the Grand Prix singles and twins the 175 was sent to the US to race and hopefully generate some publicity for Berliners, the American Ducati importers. After some time (and no great success) the bike was returned to Italy where it was eventually obtained by Francesco Villa.
Villa then bored and stroked the 49 x 46.6 mm 175 into a 55.2 x 52 mm 250. The frame was replaced by a scaled up version of the 125 Twin’s while the Ceriani forks and Oldani brakes were replaced by Marzocchi and Amadoro units. It is this form that it appears here.
In original 175 cc form the bike produced 22 hp at 11,000 rpm and weighed 112 kg, while top speed was around 175 km/h. As a 250 cc the claimed power was 39 hp at 12,000 rpm (actual 30 at the gearbox) with a dry weight of 118 kg.
Only one other 175 Twin is known to exist, in the US. This bike went through many hands before finally being restored by well known journalist Alan Cathcart.