I would advise against putting fuel up on the rack. Saftey is a reason that could be justified if it weren't so easy to find another place to mount a jerry can or transport extra fuel safer. First thoughts are, rear tires jerry can mount, rear ladder mount, or even secured in the rear cargo area.

The only time my can would be full wherever it was mounted was on a wheeling trip where extra gas would absolutely be needed. So far wheeling all over california with my Rodeo, I have not come into the situation where I could have possibly been stranded becasue I ran out of gas. I just make it a point to fill up at the last gas station before I get to the trail head.

-Ashby