COR versus Compression
Both baseballs and softballs come in a variety of stiffnesses. Softer balls are often used for younger less experience players because if a player is hit with a softer ball it doesn't do as much damage and the game is thus a little safer. More experience players usually don't like to play with these "dead" balls and prefer harder, more lively balls. Sometimes, the weather conditions,especially the temperature, may dictate choosing a certain type of ball over another. Weather conditions can be a problem since the elastic properties of baseballs and softballs change significantly depending on the temperature and humidity of the environment in which the balls are kept. When you pick up a softball you will usually find two numbers printed on the ball as ratio, something like 375/.44. These two numbers represent the compression and Coefficient-of-Restitution (COR), respectively. The compression is simply the amount of force in pounds that is required to compress the ball a quarter of an inch, and it represents the "hardness" of the ball. Compression is measured by performing a static compression test on the ball. A compression value of 375 means that if 375-lbs of force were applied to the ball it would compress by 0.25-inches. If you held a 375/.44 softball in your hand tried to squeeze it as hard as you can, and then try the same thing with a 575/.44 ball, the 575 ball would feel harder because 200 more pounds of force are required to compress the ball the same amount. The second number stands for the coefficient-of-restitution, or COR, and represents the elasticity or springiness of the ball. The COR is measured by firing a ball from an air cannon at 60-mph (or 90-mph) towards a rigid surface and measuring the ratio of rebound speed to initial speed. You could compare two balls by dropping them from the same height onto a flat cement floor. If you compared a 375/.47 ball with a 375/.40 ball you would find that the .47 COR ball would bounce slightly higher.
Science of Softballs and the Effects of Temperature
Recently, several bat manufacturers and some scientists have suggested that a better (and safer) way to control the game would be to regulate the balls used in a
game (i.e., choosing a deader or softer ball) instead of banning bats as is the current practice.
Here is a brief synopsis of .52 core balls vs. regular balls.
Most polyurethane cores are VERY sensitive to temperature, especially those with little flexibility (ie low cor. balls). Tests have shown that classic M balls can have compression fluctuations of 400 lbs. going from 40 degrees to 90. In cold temps the M balls can get to 600+ PQI while dropping all the way to 175 in 90 degrees. That is why softballs feel so much harder when you hit them in cool temps vs. hot. It is also why an M ball feels like a pillow and goes nowhere in very hot weather. The .52 275 is different from almost every other ball in that it has a very high cor. (flexible or bouncy core) and a very low compression. This combination makes the core pretty much impervious to temperature change. You'll essentially be hitting the same ball at 40 degrees as you do at 90. With that said, the .52 275 starts soft and stays soft.
The Cold Ball Risk to Bats
Broken Bat Guarantee
Bats for Sale