Margin of Error

How long is the Leroy TT course? Everyone I've asked has a different length. I've heard 7.67, 7.75 and 7.95 miles. I'll have to do a real measurement of my wheel circumference today instead of using the canned value and cross check with some topo map measurements. I'll feel much faster (well 5%) if it's closer to 8 miles than 7.6!