Posted by: SteveT () on Mon Jan 10 15:12:28 2000

Hi M. Dad,

The 0.55 number is a published specification for baseballs (the bat for practical purposes is close to 1.0, at least wood bats are.)

The problem is it is tested on a flat surface (wall.) When contacting a round object (bat) at very high velocities (say, 160 MPH), I believe it is lower. Below is a link to some research by Baumbat; a chart around the lower part of the page shows exit velocity vs. batspeed and ball speed. The numbers are far lower than would be expected given the COR of 0.55. I came up with an approximation of the variation in COR with impact speed based on published data, but it still would appear to be lower than we think, or else we're not swinging the bat as fast as our batspeed meters are telling us (more later.)

I'm going to be running some tests to see just what the COR is under varying conditions, I'll post my results when complete.

http://www.baumbat.com/PAGE5.HTM

Regards,

SteveT