The bars with teeth are used more for hard threshing crops (milo, wheat) to add aggression to the back of the rotor. We used them all the time but we harvested a larger variety of crops than it sounds like you do. I believe that the straight bars are cheaper and you probably will not notice any difference in beans and corn. If you do get the ones with teeth I would recommend hard surfacing each tooth if you do decide to get the ones with teeth again, it will add alot of life to them. Hope that answered your questions.