Hi there,
I noticed Joe Friel Bike preset zones has IMO bad sweet spot zone.
Here A Quick Guide to Setting Zones - Joe Friel, Joe doesnt wrote about sweet spot zone.
I red almost every book by Joe, in workouts examples where is description of sweet spot training is wrote that this kind of intervals should be done with 0,88-0,93 IF, so we can conclude sweet spot zone is 88-93% of FTP.
Corect me, if I wrong.