Hello everyone! I have owned this tire changer for about 15 years now and have always struggled with the clamping force of the rim clamp on larger pickup truck tires. Usually I have to clamp the rim from the outside to hold it from popping off when trying to mount or dismount a tire. I am currently working on a set of 18" rims and the clamps don't open enough to work around this issue on these rims. Does anybody out there mess with these? Is this normal for this model?