Grey Goo's reason would seen valid click here with no rear springing and girder forks at the front in that era, any bumps would feel like mountains. But I think the reason is that it opened in 1909 click here
I'm also assuming they used an 'Indian' motorcycle on the 'Indian'apolis circuit... so maybe a play on words as well for the first use bike?
The model for Indianapolis was Brooklands click here the first purpose built track in the world. The faster you went, the higher up the banking you drove. Apparently there was a severe bump at the highest part of the banking, if you hit that wrong... you were added to the list of fatalities that were sent flying over the top at high speed into the woods!:(
They didn't "test" the new circuit with a 1909 bike. It was a promotional opportunity to celebrate the upgrading of the track. World champion Nick Hayden took to the circuit on the 1909 Indian bike which had competed in the first race at the the IMS in 1909 where he reached speeds of around 40mph, he then returned to the track on a 2008 Honda CBR 1000 which he took to 150 mph on the straight. QWhen the Moto GP takes place later in the year it is estimated that the works GP bikes will hit something li8ke 200mph on the straight.
laurie53 I think you are missing the point it was a marketing exercise. Who would have mention this if it had bee done on a modern machine. click here heres the full article he did it later on a Honda CBR1000 (a Fireblade to normal people).