I've got a TC-30 with a 6" chipper and occasionally stall it out when trying to chip a large branch (ie 5 - 6" dia). My brother services New Hollands and told me that I'm at the lower limit in tractor size for that size chipper. Not a big deal if you occasionally stall it, but (in my brothers words) you don't want to make a habit of it. Now I just cut them up into lengths of a 8 to 12 inches or so and don't have any problems.