Heat olive oil in large, heavy pot over medium-high heat. Season roast with salt and black pepper. Place flour into a shallow bowl and press roast into the flour to coat completely. Cook the meat in the hot oil until browned completely, about 5 minutes per side.
Spread onion slices over the roast; pour red wine vinegar into the pot around the roast. Drizzle half the balsamic vinegar over the roast and pour the remainder around it. Spread half the crushed tomatoes over the roast and distribute the remaining tomatoes around it. Sprinkle thyme leaves over roast; drizzle hot sauce atop thyme.
Cover the pot and roast in the preheated oven until the meat is very tender, about 3 1/2 hours.
