I didn't know this could happen!

Fuel tanks are aluminum. Those front mud flaps pick up dirt, sand and road debris, then scrub it into the tank in the same spot day after day. Get yourself a piece of aluminum 1/4 inch thick, some 60 grit sandpaper and a piece of balsa wood about 2x1/4. Wrap the balsa with the sandpaper, like a sanding block and pick a spot on the aluminum. Sand back and forth in the same spot with the edge of your sanding block, moving the paper around periodically to apply fresh sanding surface. See how long it takes to work through that aluminum.

Now you know why some eye appeal accessories might not be a great idea.

 

Matt, that is another topic all together. Here you were asking about friction. Your arm is due to repetitive motion, something completely different.

 

Like Injun said its the road dirt and grit not the plastic or rubber flap and the aluminum tank.
Although a steel tank will last much longer it this situation it might wear the flap out first......or it might not.

 

Is that anything like Volvo is Swedish for sparks and dark?

 

How bout a wear plate on the fuel tank? Or "lose" the mudflap.

 

I've seen this before. Volvo has had some problems with the plastic mud-flap behind the right side steer tire rubbing the tanks. J-B weld, a bar of soap or tank putty are always good to have. Speaking from experience here...

 

....so I guess that Suave Body Wash, Active Scent, won't work as well?

 

Not quite....