My tour bike loaded is 290 lbs. With my front SA XL dyno DRUM brake it's child's play. For the 1st tour and across B.C. the 2nd tour I had an absolute POS rim caliper on the Rohloff.
I was stopping from over 30 mph in the middle of a hill to take pics in the mountains. Overheating is a laughable concept. ZERO drama in any weather.
Now with a cable TRP Spyre and resin pads on the Rohloff it stops instantly.
Before >>
Kicking Horse Pass >>
After I got the disc mount welded in Seattle. The front fork is a tandem from R+E. I put a 3" CF wrap by the clamp for the brace arm.