If you want to see the top speed you can hit, without a leadout, gradually ramp your speed up to the fastest you can cruise without starting to go anerobic (likely low 20's based on your post) then jump as hard as you can, for as long as you can still gain speed (likely about 20 seconds) That typically will result in a higher speed than just gradually ramping it up.
__________________
You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.