Preheat oven to 350°F. Line a 9x5 loaf pan with parchment paper and set aside. If you are not using parchment paper grease the loaf pan with butter.
In a large bowl, whisk together oil and sugar. Next, add the eggs, the vanilla, and the sour cream and whisk. Finally the mashed bananas and chopped rhubarb. Whisk to evenly mixed.
Add the flour, baking soda, cinnamon, and salt. Whisk till the four is evenly mixed into the batter.
Add the batter to the loaf pan and bake for 60 minutes. Test the center with a toothpick and it should only have a few crumbs once removed.
Remove from the oven and cool for a few minutes before removing it from the loaf pan. If you are not using parchment paper you will want to wait till the bread is cool enough to handle before removing.