My guess is the riders with that much skill/experience don't even try to ride that hard on the street. That is how they lived long enough to get the experience. The most experienced riders I know advised me to never push past 80% on the street, because the unexpected might just take the other 20%. 4 out of 5 times that I have broken that self imposed rule, I have regretted it, and had close calls. Riding 2-up, I may push to 50%.