Solution: Nitto R10 looks like it will work (note before anyone goes all armchair installation quarterback—it’s not really on there it’s just sitting there over the fender with one strut loosely in position to make sure it will fit before I throw out the packaging):


Brevet bike and R10

​​​​​​Part of the point was to have an option for PBP if I crack a fender in transit or something, and when I am exhausted I have trouble getting a leg over a trunk bag (which my other bike is modeling:

Gravel bike with trunk bag