Mr. Bustamente, I agree that racing events can make business access difficult. I don't blame you for the sign. It sounds like to made reasonable efforts.
My wife and I used to regularly go to a downtown Denver church.
Occasionally a charity foot race would be run downtown, and despite the church seeking reassurance that parishioners would be able to get to the church, my wife and I discovered it was almost impossible to navigate the blocked-off streets.
If there's an Ironman race next year, I hope the race organizers got your message loud and clear.