The Monza circuit opened on 3 September 1922, combining a road course and a high-speed oval with steeply banked sopraelevata corners. From the outset, the track's chief characteristic was raw speed: long straights, shallow corners, and a track that rewarded engines over aerodynamic grip. For Grand Prix motorcycles, which in the 500cc class were already among the most powerful two-wheeled machines ever built, Monza represented the ultimate test of mechanical reliability and rider nerve. The Italian Grand Prix held at Monza was one of the most prestigious rounds on the FIM Grand Prix calendar.
Monza hosted the Italian motorcycle Grand Prix across multiple eras, but the circuit's relationship with motorcycle racing was punctuated by disaster. In 1973, during the 250cc class of the Nations Grand Prix (the Italian round's name prior to 1990), a mass crash at the Curva Grande took the lives of two of the sport's most celebrated riders: Renzo Pasolini and Jarno Saarinen. Pasolini, an Italian favourite, and Saarinen, the reigning 250cc world champion from Finland, died in a single accident that shocked the motorsport world and removed Grand Prix motorcycles from Monza for years. Carlo Chionio, Renzo Colombini, and Renato Galtrucco were also killed that year during a separate Italian 500cc junior championship race at the circuit.
The scale of the 1973 tragedy made Monza politically and morally untenable as a motorcycle Grand Prix venue for an extended period. The circuit had already recorded the 1954 death of Rupert Hollaus during practice for the Italian motorcycle Grand Prix, and the accumulation of fatalities convinced sanctioning bodies that the track's combination of extreme speeds and limited run-off was incompatible with the safety standards that the sport was beginning, however slowly, to demand.
Two chicanes were added to the car circuit in 1972 to reduce speeds, but these modifications were judged insufficient for motorcycles. Grand Prix motorcycles continued to use the un-chicaned road track through 1973 before the fatalities finally ended championship racing there for a prolonged spell. Racing returned to Monza with the introduction of chicanes for the motorcycle circuit in 1981, and the Superbike World Championship also visited the venue in subsequent years.
In its classic form, Monza offered motorcycle riders a circuit defined by power and slipstreaming. The long Rettifilo Tribune straight, the sweeping Curva Grande, the two Lesmo corners, and the Parabolica provided a lap that placed immense stress on engines running at maximum revs for extended periods. Slipstreaming was an art form at Monza, and motorcycle races frequently produced multi-rider battles fought out in the braking zones at the Variante del Rettifilo and Variante Ascari. In 2010, Max Biaggi set the fastest ever motorcycle lap of Monza during the Superbike World Championship round, recording a time of 1:42.121 on his Aprilia RSV4.
The 1973 disaster at Monza left an indelible mark on Grand Prix motorcycle racing. The deaths of Pasolini and Saarinen, two riders at the peak of their powers, accelerated discussion about circuit safety standards that would reshape the calendar over the following decade. Monza's speed-first design, built in an era that predated modern run-off thinking, proved difficult to adapt to the demands of powered two-wheelers travelling at race pace, and the circuit's role in world championship motorcycle racing remained limited compared to its dominance of the Formula One calendar.
The Autodromo Nazionale Monza remains in use for motorcycle events at various levels, and the Superbike World Championship has continued to visit the venue over the years, but the track's historic position at the centre of Italian Grand Prix motorcycle racing belongs to an era that ended violently in the summer of 1973.