Originally Posted by Carbonfiberboy

This study https://pubmed.ncbi.nlm.nih.gov/23121348/
relates what is now well-accepted gospel - some dehydration is beneficial to performance, but that limit is somewhere around 3%. IMO the OP should experiment with drinking strategies to produce that 3% result, just to get the feel of it if nothing else. So that would be per pdlamb and many other sources, 1 liter/hour, which is the normal limit to push across the stomach wall. As the linked study says, you want to drink to thirst, which will mean consuming sufficient electrolytes say an hour before the ride's start, and continuing for the duration of the ride, to create a constant slight sensation of thirst, only briefly allayed immediately after drinking. Carry liter bottles, Zefal Magnum is the only one I know of and is what I use. By constantly being slightly thirsty one is assured of having the optimal blood electrolyte levels. If one has not been thirsty, one has no clue. The OP wasn't particularly thirsty on this comparatively short ride because his blood levels were in balance. Had he drunk only water, they would no longer have been so.