Given the lack of clearance on the cross bar of the brackets on the R90 coupled with the added weight of all the gear, the rear tire was bottoming out. I had chopped an extra front fender off a CB550 and bolted it to the crossbar with some countersunk bolts. 
Turns out, the bolts weren’t sunk in enough, or at least one of them, as it began to prematurely eat the tire. 
How does one resolve said issue on the road? Chuck the fender all together – problem solved.
There… I fixed it!