^^^^^+1^^^^^
Ive ridden SS and FG most of my life. Im 64yrs and tall very slim guy not much muscle to hold knees together if it was hard on knees. If these bikes were knee wreckers mine would have been blown out years ago. Like Dannihillater said its in the spinning not mashing. While i own a geared bike my choice is still SS most of the time. Keeping them in the 50 to 60's gear inches is best for all around riding. I prefer 65"for the terrain around here.