Eddie Miller remembers the early days of auto racing

Eddie Miller (7 October 1895 – 7 August 1965. Eddie drove in the 1921 Indianapolis 500.
From Borgeson, pp.9-10

I was 20 years old and had landed a job in the test house of the Elcar Company in Elkhart, Indiana. It was the fall of 1915 that I wrote to the Duesenberg brothers, in St. Paul, saying that I'd like to work for them. Fred replied saying that they didn't have any money but that if I happened to be at Elgin, Illinois, for the road race there, he'd be glad to talk with me.
I showed up at Elgin and they let me help watching the wheels in the backstretch. In those days they used to have wheels spotted around the course against the inevitable blowouts. That was my start in racing -- watching a wheel. So I went to St. Paul, worked for Fred and Augie and became a mechanician. That's how you had to start unless you had a lot of money to buy a car.
In those days the cars were all four-bangers with up to 500-cu.in. Displacement. We had no more than 5 to 1 compression ratios but with those huge bores and strokes it took a real man to crank one over.
Pretty good cars, like the Stutzes, would get up to about 105 mph and then start to shake and that was the limit of how fast you could go. Still they were pretty reliable. The Duesies were a bit faster but they were really lacking in some areas, like the brakes. Their brakes were just no damn good. It took a lot of downshifting to second gear to get slowed down and there wasn't anything like a close-ratio gearbox: the spread was about 30%!
We used to think nothing of racing for six and a half hours. The pounding was so bad that you had to wear a corset. At the end of the race you'd be black and blue, unable to breathe, and you would have lost 8 or 9 pounds. To in a race, then, with the wheels and hubs and their weight and tire size and the steering and the weight of those clunkers and the way the springs worked, it took a good man even to ride in the things, just to get hauled around. Experience really meant a great deal and it was rough to be a rookie. Loads of us stacked up in our first races. Lots got killed and lots of others never got beyond the hard-luck stage, just couldn't break the barrier. You either did or didn't.
And you can imagine the life, getting around the country by train? Five days to get from Newark to Los Angeles in wooden coaches going 30 to 40 mph, crawling 3400 miles across the states. Getting anywhere was a terrific job.
And the technology, or lack of it. Who knew anything about spark plug ranges in those days? Nobody. About gasoline? Nobody. You knew that the engine would knock but that was all you did know. You knew it was making a noise but you had no idea of how to get rid of it. Solving it took a long time.
Each oil company blended its primitive fuel differently-- anything that would start and run and not knock too badly. Nobody had any conception of octanes and we used to test gas with a hydrometer, hoping to detect something about quality. Some producers back in the teens sent us a couple of barrels of alcohol and asked us to try it. Everyone said it wouldn't work and we used it to wash parts in. It was just too drastic a change for that far back. It's easy to be very conservative when you're running on your last few bucks.
…Look at the problems of space travel today. It was like that for us. You couldn't go down to the parts store and buy a rubber cup to go on a brake cylinder because there weren't any. The Duesenberg hydraulic brake was superb for its time, but it wasn't arrived at easily. Imagine! You didn't have hydraulic brake fluid. …We had to make our won brake cups out of leather. We had to find a fluid that wouldn't freeze, rust or get hard or sticky. But except for our not having servos on both brake shoes, those brakes were as modern as the industry's best 40 years later.