I’m in my last recovery week of Sustained Power Build (Medium Volume). I have 4 aerobic endurance workouts (Townsend, Brasstown, Fletcher, and Boarstone) that are 1.5, 1.5, 1.5 and 2 hours respectively which I plan to do outside. Are there any downsides (upsides?) to merging them into 2 workouts of 3 hours and 3.5 hours?
2 * 3 hour workouts is not the same thing at 4 * 1.5 hour workouts. With the longer workouts you can expect to improve your aerobic fitness, but the downside will be how fatigued you are afterward. Anticipating the coming Ramp Test, I would probably want at least a couple of days off the bike after a 3.5 hour endurance ride.
Even a 1.5 hour ride is not a recovery ride. Under an hour is usually the suggestion from coaches. Are they recovery rides or endurance rides? If the latter then its better to combine them
A “Recovery Week” may or may not include “Recovery Workouts”. A true Recovery Workout is usually below 55% of FTP and lasts 60 minutes or less. By that definition, the workouts below are not “recovery”, but they can and are used as part of the Recovery Week.
In this case, it appears to be more of a reduction of intensity than volume: