My daughter went on an AMA super bike ride around the Sonoma race track some years back when she was a sports writer. They have to put on a stock rear frame to accommodate a passenger. She rode several laps and holding onto the brace was a must do under hard braking. She went over 135 on the back of an R1 but late braking, as every racer has to do coming into a corner, caused her to damn near climb the shoulders of the pilot and without the brace, she would have. When I remember the riders name I’ll post it.