Lnk,Dual wheels changes it's personality dramatically, and makes it a real working tractor. More traction, more weight, and a wider stance. Dual wheels are worth every penny it takes to convert it.
Let me echo what franklin2 stated... dual wheels are absolutely incredible!!! I brush cut some very steep and sandy banks by our creek. Previously, I did this with just a pair of ag tires and it worked ME really hard because I was having to use a lot of 'body english' to keep the machine on track PLUS there were many sections that I simply could not access. Then, I picked up my fourth machine and as part of the package it came with a set of dual wheels. Some time passed and after reading on mytractorforum about the benefits of the dual wheels, I pulled these from my shed and installed the set. I have not removed them since that day! The improvement FAR exceeded whatever I could have imagined. The tractor's ability to perform on hills and banks has improved tremendously. The stability is... well, the machine is going where you point it. I can cut many more areas than I was I simply could not safely reach before. The only downside that I have experienced is that if you are cutting near trees, one needs to be very careful because more than once the extra stanch can grab a hold of a tree and swing the operator and machine as the Gravely tries to climb the tree.