looking for input on blade choice. I'm looking at a D9g I have a choice between a 14'6" semi u blade or a 16' full u blade. I have never used a u .I Know you can push and carry a lot more with a u but can you grade decent with one and how does it work for stumping?
A full U-blade is designed for one thing - increased production on long flat pushes, via holding a larger amount of material in the blade. It does that well - it doesn't do anything else very well. If you want a good general purpose blade for dozing, grading, and stump-pushing, you're best advised to buy a semi-U blade. A wider blade also pulls the tractor off line much easier, when you contact a rock, stump, or even just harder ground on one side. That means a lot more steering adjustments and lost production time.
Agree wit OZ, semi U for multi task applications.
I've never seen a 9G where the blade was tight enough to run any kind of grade. The model is a bull made to push anything you get in front of it and not worry whether you are six inches too deep. It was also too big to clear anything but huge acreage and it digs the ground up like a chain saw being pulled across a wood patio deck. So if you are moving dirt, move a lot of dirt at a time.
As usual, Ozdozer is right on point. Unless you specificially need to do production moving of relatively soft material avoid a big, wide and high U-blade. These make the machine look more formidable but make the machine nose heavy and difficult to pioneer or work rocky conditions with. The semi U is a better all around choice.