You know...when I used to commute 14 miles each way, I noticed the same thing. My morning rides never quite got into that 'zone' at all. My HR was higher, my legs were just not as strong. By the afternoon commute home, all was good though.

I think my body just never really got into the grove for the morning ride. I think that's just the way some people are? Or maybe doing it more consistently can get you accustomed to it? (I never did my commute as consistently as I would have liked, back then). Now I ride daily, but it's so short that I don't even think of it as a 'ride'. It also happens to be all down hill on the way to work, so that probably compensates for any physical sluggishness and I've never noticed it.

I'm glad you reminded me of this, actually. In a little over a week, my commute is going to go to 19 miles each way. Remembering this will help me get past that sluggishness in the morning (at least mentally)! I think the best thing to do is NOT look at your speed or HR in the morning and just use the time to enjoy the ride for the scenery, the weather or the fresh air.