First and foremost, here is a good article shedding light on the inaccuracies of the combine's timing methods. It's truly bizarre what they do. Most teams keep track of their own times anyway. So, for example, if Hyde runs a 4.48 for the Giants, they'll probably go by that time and not the combine time. I wouldn't put too much stock into these "official" times. If you swing your hand up before you even start moving or lean forward, it could turn a 4.3 into 4.4 or 4.5. A crisp, clean start is a must for a great time. And that's what Hyde didn't do. He budged forward before he even moved, I believe in the first few steps he pulls his hamstring. Check out the video to see for yourself.
http://www.nfl.com/videos/nfl-combine/0ap2000000328416/Carlos-Hyde-injured-during-40-yard-dash
Even with a bad start and a pulled hamstring, he still managed to pull off an "official" 4.66. But did he actually run faster? I think so. I decided to hand time his dash forty times and create a composite hand-timed forty. The average came out to be 4.57. That's my time for Carlos Hyde's "terrible dash." Ask yourself, does De'Anthony Thomas run a 4.5? Well, his "official" time indicates so. I hand-timed DAT's dash 3 times. The results? 4.36, 4.35, 4.34. We all thought he had 4.3 speed. His tape shows it. His run shows it. His "official" is 4.5? Not buying it. I'm done with these laser timed forties. Give me a stopwatch, a pen, and a piece of paper and I'll tell you the time.