Depends on the road, how I feel, traffic, etc. According to my cumulative Garmin data my max speed at one point was 49.7 mph. I know where I was when I hit this, I was not looking at my Garmin but focused on riding. Road was excellent, no cars, I was on the drops and let 'er roll. But I don't plan to make a habit of this. I'm pretty comfortable with mid to upper 30s. I will hit low 40s fairly regularly, but that's about it. I sometimes intentionally stay on the hoods to help control my speed with wind resistance.