The size of the 500 field is steeped in tradition
Thirty-three isn’t just an Indianapolis 500 number, it’s a tradition; and believe it or not, it’s been so for more than a century.
To qualify for the first 500, in 1911, cars had to travel a quarter-mile stretch of the front straight within 12 seconds, a 75-mph average. Forty-two cars tried, two failed. The rest took the green flag.
Trouble was, 40 cars racing simultaneously at Indianapolis Motor Speedway was deemed too many. Next year, the historic adjustment was made. Given the track’s size—2.5 miles—officials decided one car for every 400 feet was appropriate.
But the early decades didn’t cooperate. Factoring in an evolving auto industry, then WWI and the Great Depression, the 500 started with 11 rows of three only three times over the next 22 years. In that time, there were as many as 42 starters in 1933, as few as 21 in 1916. Twice there were only 22.
It’s surprising there were 40 cars that first year given the whopping $500 entry fee and only the top 10 finishers receiving prize money. Yes, the endurance test paid $10,000 to win, but it took finishing 10th to recoup the entry fee.
After year one, manufacturers were limited first to two entries each, then three. There were so few cars in the second and third years, IMS dropped the entry fee to $200, drawing 40 cars for the 1914 race, many homemade specials.
In 1916, the last race before the U.S. entered the war, cutbacks included race distance. It was 300, not 500, miles, and took track owners Carl Fisher and James Allison rounding up more than 12 cars
just to get the field to 21 starters.
The 500 struggled for competitors even after the war. In 1921, there were only 23 starters. IMS increased the maximum number of entries for the 1930 race to 40. It worked. Thirty-eight started, and for the next three years, the numbers were the highest in 500 history: 40, 40 and 42 starters. The latter figure was allowed because having a single-car 14th row looked odd.
What made even less sense was putting so many competitors in peril. It was decided after the 1933 race that the accident rate was too high, so for the ’34 race it became standard to have 33 starters.
Eleven rows of three has been the alignment for every race since then, with three exceptions. In ’47, several top drivers who were members of the American Society of Professional Auto Racing challenged the size of the purse, asserting it was too small, leading to only 30 entries. In ’79, when CART was formed, the field went to 35, and 35 were permitted again in ’97 when the Indy Racing League used a 25/8 rule designed to ensure starting spots for 25 IRL series regulars. Two cars with no such guarantee were among the fastest 33 in ’97 and were allowed to compete.
Otherwise, the 500 has rolled off 33 cars each year since 1934. Like we said, it’s not just a number, it’s a tradition.