What is the right gearing for VIR North? I was watching AMA Superbike today and I thought I heard that they were pulling 170 mph on the main straight. That sounds like 1 tooth down from stock in the rear, but the question is would there be enought time to get there? Since I am not going to buy a 42 tooth sprocket I guess I'll just go back to stock? 15/45 tops out around 140-145 mph it seems.