Percy Roderick Coleman was born at Mountain Road, Ngaere, Taranaki, on 26 January 1897, the only child of Sarah Jane Gifford and her husband, William Coleman, a traction-engine driver. He attended school, mainly at Takapau, in central Hawke's Bay, until he was 12, when he became a motor mechanic in Palmerston North. Despite an accident with a workshop grinder which cost him the sight in his left eye, he began racing motor cycles at 14. His first event was at the Ashhurst horse-racing track in 1912, when he rode a 3½-horsepower Humber. Motor-cycle racing on one-mile, grass horse-racing tracks was a popular sporting event in New Zealand from before the First World War until the mid 1930s. The most popular venue was Takapuna racecourse, which drew crowds of up to 20,000.
In his second year of racing Coleman won the New Zealand five-mile lightweight championship, riding a Douglas motor cycle at Trentham racecourse. In 1915 he graduated to a seven-horsepower Indian, and at the age of 18 he won his first New Zealand heavyweight championship, a competition he was to dominate for the next 15 years. An aggressive rider, Coleman took the corners so closely that he would often bark his knuckles on the railings. In 1916, riding an Excelsior (or 'Big X'), he set an Australasian record of 17 minutes for an 18¾-mile event at Masterton. Two years later, back on an Indian motor cycle, he won the Australasian heavyweight championship at Sockburn, Christchurch.
In 1919 Coleman visited the United States, where he competed in two events as an official rider for the Indian Motor Cycle Company. The first was a 200-lap race on a one-mile asphalt track at the Ascot speedway in Los Angeles. He finished sixth, but was the first rider home on an Indian. His second ride was a 200-mile road race at Marion, Indiana, in which he was forced to retire with engine trouble.
Returning to New Zealand with the nickname 'Cannonball Coleman', he began riding Harley-Davidson motor cycles, with great success. During the 1920s Coleman made a series of supervised attempts to establish world-record times on one-mile grass tracks. He is said to have eventually held all world grass-track records for distances up to 20 miles, and progressively lowered the one-mile record from 48 seconds in 1923 to 44.8 seconds in 1929. In 1930 Coleman was chosen as New Zealand's first official representative at the Isle of Man Tourist Trophy races, but poor machinery eliminated any chance of success.
Percy Coleman married Annie McNaughton at Frankton Junction on 16 September 1925; they were to have two sons and two daughters. The same year, he opened a retail shop in Wanganui, selling and servicing bicycles and motor cycles, and acting as a distributor for Harley-Davidson; he later expanded into radio and refrigerator repair. He was also a keen photographer and motion-picture enthusiast.
Another of Coleman's passions was aviation. With a partner he purchased a biplane around 1912, but could not get it to fly, which was perhaps fortunate as his only flying instruction had come from a book. He then attended the flying school at Sockburn aerodrome, and in 1924 purchased a single-seat Whippet biplane, manufactured by the Austin Car Company. After towing it behind a car from Hamilton, Coleman flew the Whippet from a farmer's field near Palmerston North, there being no aerodrome available. The unreliability of the aircraft's engine, however, restricted his flying activities. On one longer flight, he was forced to land on a beach; on another occasion, the Whippet crashed on take-off.
Percy Coleman retired from competitive motor-cycle racing in the early 1930s, and concentrated on expanding his business. By the 1960s it had become a nationwide motor-cycle importing and distribution company, managed by Coleman's sons, Rod and Bob, both of whom were leading motor-cycle racers. In 1954 Rod Coleman achieved his father's ambition of winning the Isle of Man Tourist Trophy race, and in 1964 Bob broke his father's 1929 world one-mile record. Percy Coleman died on 20 April 1965 while visiting his daughter in Salisbury, Southern Rhodesia (Harare, Zimbabwe). He was survived by his sons and one daughter; his wife Annie had died in 1958. The company was eventually sold to Suzuki New Zealand in 1984.