Originally Posted by p66
My rear tires are a smaller circumference and my speedo is not accurate. I don't even bother to look at it on straights. It must be the drag from my go pro.
Mark and Robert are both referring to their speedo readings which are over overstating actual speed due to BMW's speedometer safety factor and their smaller track tires. Your 139 mph is probably the max for a 1M at COTA.