Moment of Inertia (MOI) governs how a bat feels and is a more meaningful measure of how well it will swing for you than the actual weight of the bat. Bat speed, not bat size nor weight, is the main factor in driving a ball. Bat speed is affected by a number of variables including bat length, bat weight and bat Moment of Inertia (MOI) which is often referred to as swing weight or balance point.
The distinction between light or heavy swing weight really boils down to the location of the balance point (or center-of-mass) and the moment-of-inertia. The closer the bat’s balance point is to the handle, the easier it is to swing. The basic concept is that it is not the total overall weight of the bat which determines how fast you can swing a bat, but the way that weight is distributed along the length of the bat. For example, a bat with a balanced point closer to the handle will feel lighter and swing faster than an end loaded bat. This is true even through both bats are the exact same weight on a scale.The higher the rating the higher the MOI and the heavier the swing weight.
As a general rule, most players can hit a ball further with lighter (really low MOI) bats. It is only the biggest home run hitters, who can hit the ball further with a heavier (really higher MOI) bats. Also, lighter bats provide more bat control during the swing phase
Good players who are strong tend to prefer bats with a heavy swing weight because they can swing the bat fast enough and the extra inertia of the bat makes for a more effective collision with the ball. Players who are not as strong, or who cannot swing a heavy bat quickly, tend to opt for bats with a lighter swing weight so that they can increase their bat-swing speed and obtain faster batted balls that way.
Here’s a brief Easton video on MOI…
Obviously MOI is only one factor to consider with material, handle flex, mass and design (1 or 2 piece) being the others. But, it is often ignored or misunderstood. You should take the time and effort to decide what MOI is best for you and what the ratings are for the bats you’re considering.
If using a BESR certified bat is the moi regulated? If it has a highter MOI and therefore a highter bat speed is the barrel somehow de-tuned to meet the regs? What does the 60 MOI of the SV12 against the 90 MOI of the Stealth mean, as it is just an easton #, does it move the balance point (I don’t mean feel,I mean actually setting the bat on a physical point and moving it back and forth until it does not tip) on the shaft out 1mm or 6″ or what? I can not find any info on what to me seems the most important factor in choosing a bat.
To PD154: The balance point will determine the MOI or Swing Weight of a baseball bat. The higher the MOI, such as a 90 rating on the Stealth IMX, the more end loaded the bat. The lower the MOI rating the more the weight is toward the handle, or balanced. Easton does an outstanding job of providing the MOI, and handle flex rating of all their main bats. They have a MOI option for everyone (although you might not like the material of the MOI you like). Others will just say “balanced” or “end loaded” to provide some information And then there are those that don’t give any information.
BESR testing DOES regulate MOI. There is a maximum and minimum requirement.
Easton does not provide the MOI for their bats. They provide their MOI rating system, which has little to do with thier bat’s actual MOI. These numbers, like the 90 and 60 mentioned above, only let customers know which models feature more of an end-load, which can be easily determing by just picking up a bat.
The actual MOI of a 34″ SV12 (60 rating) will be higher than that of a 33″ Stealth (90 rating) because of the additional mass, yet the rating system does not reflect this fact. MOI has become an advertising buzzword like “flex ratings” that sounds high-tech… most people do not know what it means or how it relates to hitting a baseball. These buzzwords have very little measurable effect. It’s marketing… not science.
Bottom line, hit the bat and don’t listen to the BS. If you like it, then it’s a good bat.
Would someone please explain “handle flex rating” and how it interacts with MOI?
Generally speaking the handle stiffness does not affect M.O.I., it is the balance point of the bat. You can read more about handle flex on the site here.