Make sure if you put it on the roof that you do not lay it flat on the rubber roof otherwise you well probably be in for a bad surprise when it wrecks the roof by rubbing it. Anything that is not attached is going to move and vibrate some which well wear on the roof.
I want to know how you are going to get the 80 plus # up and down from a roof that is 12' off the ground. :E I know I sure wouldn't want to do it.
As far as on the front of the rig I drove our truck from Arkansas to Alaska and back last summer, over 11,000 miles and I had a front rack with a tool box on it and never had any heating problems. A tire would give more air flow than my tool box did. Also on my F550 I had in 2006 I had my tire mounted on the front of it (as there is no mount under the truck on the chassis cab models) and never had a heating problem on it.
Take a look at the sticky section
Photo thread and you well see a lot of people use front end carriers. I think if there was a problem with it one of us would have noted it here.
Butch
I try to always leave doubt to my ignorance rather than prove it
2021 Winnebago View