We've probably all heard the stories about how some Pro Day tracks might be a few feet (or even a couple of yards) short of 40 yards, so that scouts have to measure to make sure the distance is correct, or that a wind (usually of around 20 MPH or a little less) can effect a runners 40 time (so they include whether each run was against the wind or wind aided, from behind them). However today RotoWorld.com has 2 stories from Gil Brandt about this years Pro Days that might be new wrinkles (I'm sure 1 is any way) to watch for.
The 1st story reguards Rutgers WR Mohamed Sanu's reported 4.41-40 Pro Day time, after posting an "official" Combine 4.67-40 time. Brandt credits this early report to Sanu's agent, and reports Sanu's Pro Day 40 times were actually 4.54 and 4.55.
The 2nd report from Brandt is funnier still, it reguards Temple RB Bernard Pierce, who ran an "official" Combine 4.49-40. According to Brandt Pierce's Pro Day track was tilted, helping him to run a 4.34-40 downhill, but a 4.50-40 running uphill.