Here is my latest attempt to gain some heel clearance, thought i'd share. I used Madison Ridge rack without its adjustable legs, with the Tubus extension plates instead.



I got the idea from mtbr forums, someone uses it on his fatbike. I am quite happy with how far back it sits now, the height is also fine, there is even some room for lowering it if I want to do some more drilling.

For a test I loaded about 20 kilos/45 lbs in the panniers and did some climbing out of seat leaning the bike a lot. I must say that lowering the rack improves stability in comparison to my initial setup, but the new rack feels a bit flimsy after Tubus Cargo. It's made of aluminium, so less options for repairing it in the field. Compromises... Looking at the tout terrain integrated racks design now...