The front-wheel drive (FWD) version of the Miller 91 was 50% more expensive than its rear wheel drive counterpart. Together, both models were a dominant car in American racing. Millers usually filled more than half the grid at the Indianapolis 500 and won the event outright in 1926, 1928 and 1929. It was the only series production model to race Indianapolis and was surrounded by various American specials to complete for these victories.
With the 1926 regulations that limited engine size to just 91 in³ (1.5 liters), Miller had to create a new engine for his new cars and his existing customers. These were built to same winning standards as Harry A. Miller’s Indianapolis winners. Almost the entire car was forged and fabricated on site and each was a engineering marvel, particularly the expensive front-wheel drive variant of the Model 91.
At $15,000 USD, the 91 FWD was one of the most expensive cars available. This didn’t stop at least 10 FWD cars from being made. Many of these had detail differences but the overall design was the same.
Possible due to a de Dion Tube front axle, the FWD setup let drivers power sooner out of the corners and put most of the weight over the front wheels. Furthermore, the bodywork was much lower due to lack of a drive shaft below the driver.
To make up the lack of displacement, Miller and his team fitted a centrifugal supercharger. Some of the very first blown Millers appeared in 1925, on the 122. By the time the 91 in³ formula was set, Miller could already produce more power from the smaller displacement. With nearly 250 bhp on tap, the 91 could top out 171 mph. Like the 122, Miller used a DOHC setup which Bugatti would later use on the Type 51.
Millers dominated the 91 in³ (1.5 liters) formula and filled most of the Indianapolis field from 1926 to 1929. Unfortunately, the 91 was the last successful car sold by Miller. His company failed with crash of 1929 and he was bankrupt three years later.