That is one thing I've notice with all the tractor manufacturers. None of them list the maximum tread width in their specs. Sometimes it can be dug out of the depths of an online owners manual, but often it just simply isn't offered up. Many times if it does show re-setting them it doesn't tell you how wide that makes the tread width. I have 12 acres of billy-goat land that likes to grow blackberry briars, so I'm very interested in how wide I can set the wheels.
Edited to add: Can the fronts be spaced out any?