Change up speed?

The arm speed should not change on the change up. The deception is everything looks the same to the batter except the ball is coming in slower. A good change needs to have a little sink and run on it as well. The speed difference will vary with pitchers. Some guys might throw the fb around 80 and the change around 73 or so. But it varies.

Agree with Coach May, speed differential is just one of several ingredients in a good changeup. Location, movement, deception are probably the three main things.

To answer your question... about 12-13 mph difference is the norm. Someone much smarter than me once figured out this was the ideal speed difference. Has to do with timing. Too fast can be like a slow fastball to the hitter. Too slow is easier for the hitter to adjust to.

I have seen some good Big League pitchers with 7-8 mph differencial. But there location, deception and especially the movement they get is outstanding.

i have to agree with PG, a 10-12 mph difference is about right, my fastball is usually in the 90's and my changeup is 80-81 usually, and it seems to work out pretty well. The main key with the changeup though is to make it look like a fastball in every aspect but speed.

I read somewhere that you wanted to be around 10% reduction [at least] from FB to change. I think less % should be offset by more movement. Windmill Jr has hit 80 with his FB, 62 with down/side movement with the change; works for him.