I've about decided to remove my dynamo wheelset this weekend because my commute is mostly in daylight now. I'll go back to using my rechargeable LED lights until next fall. I've enjoyed the dynamo lighting but it has definitely slowed me down. Although my bike doesn't "feel" slower, my data show me that the dynamo wheel reduces my average speeds by 0.5-1 mph, which adds at least 5-10 minutes to my commute times. It also makes me feel more tired.