Maybe (but I don't really think so) it's psychological - but sustaining that speed was breaking me down, yet one mph slower and I was fine... oh, and FEELING GOOD instead of feeling crappy. No pain, no problem!
No, I think it is.

When I ride with faster riders and I am hanging with them, or even worse... in FRONT of them... I totally start thinking, "What the hell am I doing here? I can't ride this fast! They are faster than me!"... etc... etc... Before you know it, I am falling behind.

I did try to talk myself positive last Sat., but dang, I totally lost my confidence when I found out I had no other group to ride with for another 30 miles.

In the end though, our bodies only do... what the do. Right? Sounds like you rode your ride, just the way you needed to, and it worked. It's always nice to not take a SAG wagon... huh?