Place corn into a large pot with enough water to cover. Bring to a boil, then cook until kernels are tender but crisp, about 5 minutes. Drain and cool for about 5 minutes.

Use a knife to scrape corn kernels from the cobs into a large bowl. Add bell pepper, onion, tomato, olive oil, balsamic vinegar, and garlic. Toss to combine and season with pepper. Chill for 15 minutes before serving.