Kirby, I relocated the tank to the rear for 2 reasons.
1- To balance the weight of the rig more in line with the center of the rig and not on the sides.
2-Add some more weight on the rear axle for better traction.
No the tank doesn't bash on rocks due to the design. If you look at the picture you can see that the bumper has taken some hits but not the tank. When we designed the bumper we measured the angle of departure from the bottom of the tire to the bottom of the bumper and copied it on to the tank. We measured the angle from the middle of the axle to under the rig and that gave us the angle for the bottom of the tank skidplate. I hope this makes sense

The reason your brothers are always bashing their tanks is the angle of departure on their tanks is less than the bumpers. Bang getting off a ledge.
I gave a lot of thought to the issue of spending the extra money on the 37x17x12.50 due to price and what would I gain besides looking cool and came up with the following reasons. Justifying the 37's was easy but justifying the 17in. rims was harder.
1-The first one sounds simple but a lot more complex than it sounds. The bigger the tire the smaller the rock, the less stress on your rig. Take a 35in. and a 37in. tire and draw an imaginary line on the front where the curvature of the tire is neutral. Beneath that line the tire curves down and above the line the tire curves up. Any rock below the line you roll over, any rock above that line you meet resistance. The advantage is you can pick different lines when rock crawling with bigger tires. The other reason for going to 37's was better clearance under the pumpkins. I now have almost 12 in. underneath.
Picking the rim size was a different matter. The price of 17's over 15's is crazy. When I had the 35x15's I liked the amount of sidewall flex it had. The Navajo drove great on highway and great on the rocks, it was very stable. I was afraid if I went to 37x15 this extra sidewall flex would be a problem both on highway and offroad. Going with the 17in. gave me the same ratio. Sidewall flex is good but too much creates sway, specially on short wheelbase rigs. I'm very happy I went with the 17's.
Hope this answers your question
