Physicist Discusses BBCOR Bats
LOU PAVLOVICH, JR.
Sept. 3, 2010 Edition)
- CHAMPAIGN, Ill. — The performance level
of non-wood bats that meet the new 2011 NCAA standard is expected to be at
least five to six percent less than bats utilized last season, according to
Alan Nathan, a member of the Baseball Research Panel who advises the NCAA on
issues related to bat performance.
- The new non-wood bats which meet the
Bat-Ball Coefficient Of Restitution (BBCOR) testing protocol must pass a
number of performance standards, including Moment of Inertia and BBCOR.
- The Moment of Inertia test prevents new
bats from carrying the bulk of the weight near the handle which makes the
bat swing faster than barrel weighted bats. For instance, a 28-ounce bat may
feel like a 23-ounce bat to a hitter because of the weight placement in the
- For that reason, a minimum allowable
Moment of Inertia for different length bats is now in effect. The BBCOR test
essentially limits the trampoline effect of bat barrels to that of wooden
- With the new changes, non-wood bats
utilized in 2011 and beyond with the new BBCOR standard should perform very
close to wood bats, according to Nathan.
- The new bats will be less potent than
non-wood composite bats utilized during the 2009 season which were outlawed
by the NCAA Rules Committee for the 2010 season.
- Those bats, which were NCAA legal at the
time of purchase, could be artificially aged by a process called “rolling”
which resulted in a boost in bat performance.
- Bats were compressed along the barrel
between top and bottom nylon rollers or hard rubber rollers.
- The resin and glue broke up as the
rollers were tightened down in a precision process over the entire barrel of
the bat leaving the area more flexible with a maximum trampoline effect when
balls hit the barrel.
- The BBCOR standard eliminates the
possibility of bats performing at a higher level by rolling non-wood
composite bats since this has been factored into the new protocol.
- Nathan, who has been a Professor of
Physics at the University of Illinois since 1977 with a specialty in
experimental nuclear/particle physics and written over 80 articles in
scientific journals, took time out of his hectic schedule to explain how the
new BBCOR testing standard on non-wood bats will impact teams which utilize
NCAA rules next season.
- Composite Bat Testing?
- Nathan was asked if non-wood composite
bats will be approved for NCAA play in 2011.
- “There is no question hollow composite
bats will be able to meet the new BBCOR performance standards,” said Nathan.
- “That is well within the means of bat
manufacturers. The problem with the hollow composite bats used during the
2009 season was that they got better with use. It is pretty well understood
how the science of that happens. What cleaver people discovered was that
they could accelerate the break-in time by ‘rolling’ these types of bats.
That’s an illegal act.
- “When the problem was realized, there was
a moratorium put on these bats in the fall of 2009 and through 2010. We
understand how metal bats work and how to regulate them. With hollow
composite bats, it has been more difficult to regulate them with their
- “But we came up with a way to do it. The
way we did it was to perform our own accelerated break-in tests by rolling
bats. We test the hollow composite bat, roll it, test it again and roll it
and repeat that procedure until the bat fails as it breaks or cracks.
- “At no time during that process can the
bat exceed the BBCOR limit. In essence, the hollow composite bats get better
and better until they fail. Just before failure, the bat performs at its
highest level. We are saying that at the bat’s highest level, it must be
below our BBCOR limit.”
- Nathan said this procedure has been in
effect for amateur softball to regulate non-wood composite bats.
- “We are trying it out with baseball for
the first time, and we will have to keep tabs on what is going on to see how
well the procedure works. It is a fairly detailed procedure on what we
actually do. Hopefully this will fix the problem. If we need to do something
else, we will be prepared to do it.”
- Nathan was asked how closely the new
BBCOR approved bats will perform to wood bats.
- “Very close. When the standard was set
up, we had a decade worth of data on how non-wood bats performed and how
wood bats performed.
- “With the BBCOR approved bats, the
average seems to be .48 or .49, and at the very upper level, .50. The limit
was at .50.
- “What these figures mean is that there
will be no trampoline effect for the new non-wood bat barrels. From a
trampoline aspect, the barrels will react just like wood. A wood bat is
essentially a perfectly hard surface. When a ball hits a wooden bat, it has
the same trampoline effect as a ball hitting a massive, rigid floor.
- “In the past when a ball hit a hollow
non-wood bat, then the surface of the bat compressed a little bit. Some of
the ball energy compressed the barrel wall of the bat by a little. The net
amount of energy lost in that collision was reduced, so you got a bigger
- “The trampoline effect can really be seen
if you bounce a ball off a tennis racket compared to a rigid floor surface.
The ball will bounce much higher off the tennis racket.
- “The technology of creating a high
performing non-wood bat has been to find alloys of aluminum that make the
walls thinner and thinner so you have more and more of that trampoline
effect without denting the surface.
- “When hollow composite bats first came
out, it was an entirely new technology. It almost seems limitless on how big
of a trampoline effect you can get. When the first Miken bat came out,
representatives of other bat manufacturers were in awe of how far players
could hit balls with the hollow composite bats. Miken was one of the
pioneering companies making composite bats. Now all of the bat companies are
making hollow composite bats.
- “Since there will be no trampoline effect
for the new non-wood barrel bats, the aluminum only bats must have thicker
walls in order to comply. In the case of hollow composite bats, just like
manufacturers can ramp up the trampoline effect, they can reduce the
trampoline effect with various tricks. The bat manufacturers won’t have any
trouble satisfying these new standards.”
- Performance Of New Bats
- Nathan was asked what reduction in
performance the new BBCOR bats will yield to hitters in 2011?
- “With the previous standard (BESR), the
best performing non-wood bat outperformed wood by about five percent and
maybe as much as six percent.
- “That five or six percent will now be
reduced to zero percent with the new BBCOR bats. Roughly speaking, that
translates to about five miles per hour less off the new bats which is the
same as wood bats. Currently, BESR certified non-wood bats outperform wood
bats by five miles per hour. In effect, what we are doing is removing that
five miles per hour gap. Non-wood and wood will perform at the same level in
terms of batted ball speed with the BBCOR standard in place.”
- Nathan was asked how a five percent
reduction in bat performance will impact offenses.
- “That’s a very difficult question to
answer. But one thing is sure. There will be fewer home runs. However, it is
not clear that batting averages will come down. Despite the fact that the
BBCOR standard bats will in theory be the same as wood bats, there are still
differences between wood and non-wood bats.
- “The Moment of Inertia (MOI), or swing
weight of a bat, will be less than a wood bat. This means the bat will be
more easily maneuverable.
- “It doesn’t mean there will be any
advantage when it comes to ball speed off the bat. In fact, there is no
advantage with the minimum allowable Moment of Inertia figures we have in
place for the different length non-wood bats with the new standard. A batter
may get a higher swing speed with a lower MOI bat, but that is almost
completely compensated by a less effective collision with the ball because
there is less weight behind that collision.
- “The effect of MOI on bat speed is
minimal at best. However, there is a positive benefit with a lower MOI in
that a batter will have a quicker bat. You can wait on the pitch a little
longer and adjust your swing once you have committed to the swing. You can
do this more easily with a non-wood bat that has a lower MOI than with a
wood bat. Even though you might not hit the ball any harder with a non-wood
bat, you might make good contact more often.”
- Nathan was asked if the MOI figure for
every new approved bat will be made public.
- It is fairly easy to get the MOI number
for softball bats on the market which allow batters to know what swing
weight will be better for them than other bats even though bats may be the
- “Maybe manufacturers ought to put the MOI
figures on their bats. Once a hitter realizes that the MOI determines how
the bat feels to him, then he can go looking for a bat in that range of MOI.
It would certainly save him a lot of trouble when he is trying out bats from
different manufacturers. We aren’t requiring any manufacturers to put the
MOI figures on bats. But it might not be a bad idea if manufacturers do that
to help hitters.”
- Nathan said when bats are tested at the
Baseball Research Center in Lowell, Mass.,
they are stationary with no movement.
- “On the field, a baseball is moving and a
bat is moving,” said Nathan. “What matters from a physics point of view when
measuring performance is that the relative ball/bat speed be reasonably
close in laboratory tests. In the field, the batter might be swinging 65
mph, and ball might be coming in at 80 mph. Combined, that is 145 mph. So we
fire balls out of a high speed air cannon into a stationary bat somewhere
between 135-140 mph.
- “A lot of work has gone into determining
the appropriate instrumentation to find out how bats react to balls coming
into the barrel at that speed.
- “We measure the speed of the ball as it
approaches the bat. When the ball hits the bat, we measure the speed as it
bounces back. All of our measurements in the BBCOR come from taking those
numbers and running them through different equations.”
- BBCOR Protocol History
- Nathan said that the switch from the BESR
standard to the BBCOR protocol was first recommended by the Baseball
Research Panel which he serves on.
- “Our committee felt a BBCOR standard was
a better correlation on how the bat performed in the field than the BESR.
However, the decision of where to draw the line in bat performance was made
by the NCAA Rules Committee.”