The Wt. Probably. A D-11 is used in open pit mine's, mostly. The ground is hard pan/ solid A D-11 would probably not be good at pushing that dusty soil, burnt ground. To meany drop offs on fire line building. YES a D-11 is big and can push tons of ground, but and I say but. The machine still needs a stable footage. For Fire line cuts you need a mid size like the D-6 it can cut a lot of Dirt, plus less turning radius. A D-11 would probably be more of a slower builder of fire breaks, because of size and Wt. YES they can still roll over on hilly terrain. Also just think of size trying to get to fire line. They are to, to big to trailer down road ( front blade must be removed) . In open pit mine's they have a special off road carriage truck to move them around. The carrier is overweight for any public right of way. They would SINK roads, break water main or gas crossing, traveling over top of them.

@@rp1645 appreciate the reply. I saw some comments about them being used for Huge Wildfires by some, and was curious about the difference. I will keep these differences in mind. I am thinking about my future and possibilities.

@@Tuner010 another difference on a D11 vs a D6 would also be the type of blade/movement of the blade. A D11 would more than likely have a 4 way blade. A blade that enables you too move up and down as well as at an slight angle too the left and too the right. A D6 would more than likely have a 6 way blade. Up and down and side too side like the D11, but also at an angle too the left and the right. Mr. @RP gave you the beginning info but you sounded interested so I thought I'd give you some more.