Originally Posted by sureshs
And what would be a realistic speed if I want to be in a wheelchair and want most of the serves to go in? For flat and spin please.
For a wheelchair player 84mph is the absolute max a ball can be hit with no spin (were that possible) based on average contact point heights. With spin theoretically you could increase this to ATP speeds if you could move the racquet fast enough, but realistically the best male servers on tour are serving at around 100mph which requires around 2000rpm to go in from the average contact height.