Q: Is the tank vest backed with anything to prevent wear marks on the paint?
A: No, the tank vest is not backed with anything to prevent wear marks on the paint. Unfortunately anything attached to the tank - whether via magnet or straps - can cause wear marks over time. We've found that the best way to minimize these wear marks is to strap the tank vest down tightly.
The photos below are of a KLR650 with the IMS vented tank. The Tank Vest on this bike is the original prototype. It's been run over 6000 miles on pavement, dirt, gravel, across streams, and on trails. It's been exposed to gasoline, oil, road spray, rain, and it's gotten intimate with the ground (more than once).
This Tank Vest, the prototype, the very first one made, has performed incredibly well over the years. The only reason it is removed is to demonstrate how easy it is to install. As you can see, there is little wear on the tank or the Tank Vest.
If you look at the picture of the tank area underneath of the tank vest, you'll see that the paint shows very few signs of rubbing or wear, considering that it's been several years and 6000 miles since it was put on the bike.