Wall Thickness and Its Effect On Bat Performance by Mark McDowell, Ph.D. and Ronald D. Noebe, Ph.D.

How does wall thickness affect a bats performance is one of the most asked questions in softball today. We will attempt to shed some light on this topic by giving an overview of discussions we have had with bat manufacturers and results of wall thickness measurements from a number of bats that we have managed to collect from every major sports company. This article will be updated in the future as we continue to test some of the newest 1997 bats that are just arriving on the market.

Wall thickness affects the amount of elastic deformation a bat wall will undergo during a given impact, or in softball lingo, the "trampoline" response of the bat. This is simply how much the walls will flex and rebound when struck by a softball. The thinner the walls, the greater the walls will deflect for a given bat/ball impact, and consequently the more energy is returned to the ball. This results in the ball rebounding off the bat faster and most players see a noticeable increase in the distance the ball travels. While this is definitely true for the new thin wall bats, the big trade off is durability. Durability of the thin wall bats is never stressed, instead the point that is stressed is that you can hit the ball farther and not that these bats are only good for a few swings and then you will have to buy a new one. The question is whether a bat is worth the money if it can guarantee you 20-30 more feet and give you the ability to hit a home run while only lasting a few good swings. Most players would answer yes to the above question and this is the main reason why the thin wall bats are so popular today.

As we have discussed in a previous article, the two most common alloys for bats today are Alloy 7055 (C405™) and Alloy 7050 (Cu31™). While C405™ is a slightly stronger alloy than Cu31™, that doesn't necessarily mean that your C405™ bat is more durable since chances are your C405™ bat has a thinner wall thickness. Therefore, while C405™ is a stronger material, because there is less of it in your bat, these bats may not be any more durable than Cu31™ bats and depending on wall thickness, they could actually be much worse. This is the reason many players feel that their Cu31™ bats are "better" than the C405™ bats, since they perform quite well and often last much longer.

These are the bats that come with a guarantee against denting for a period of time ranging from 30 days to up to a year. The best warranty bats on the market are the C405™ bats because they give you a performance advantage over Cu31™ and are just as durable. We found that the wall thickness of the C405™ warranty bats (0.072" average wall thickness) were on average 5% less than for comparable Cu31™ bats (0.075" average wall thickness) because of the higher strength alloy.

Bats with a warranty last much longer and are more durable. If something should go wrong with the bat such as denting, most companies will replace it with no questions asked. Besides, the best way to add 20-30 more feet to the ball is to change your bat mechanics not by changing bats. You really need to generate a tremendous amount of bat speed in order to dent a warranty bat (assuming that the temperature of the ball is above 60^oF). A typical 29oz warranty bat has a 24 or 25oz shell with a 5 or 4 ounce end plug and a wall thickness in the range of 0.072" - 0.075". In terms of overall performance and durability and ease on the wallet, the C405™ warranty bats are the way to go for most players.

These are bats that do not meet the wall thickness tolerance and can't be guaranteed against denting for any length of time. For the power hitter, these bats usually last between 3 and 10 good swings before denting occurs. You can definitely notice an increase in speed off the bat as well as distance when the ball deflects off a no-warranty bat because of the increased trampoline effect. The surprising thing is that these bats are junk bats and if so many average players would not want them, they would probably be given to the major players to use in batting practice. What is even more surprising is that these bats cost more than the bats with a warranty!!! How many people would buy a product without a warranty and be happy about it? Yet there seems to be thousands of softball players with that attitude when it comes to bats. If you have the means to keep supplying yourself with these bats, then you will have premium performance and pay a premium price.

The wall thickness of no-warranty bats range from 0.069" to 0.071". These bats tend to dent regardless of the temperature of the bat or ball in any kind of weather. Most of these bats are extremely end loaded due to the fact that the walls are so thin and the difference is made up in the end load. A typical 29oz no-warranty bat has about a 22 or 23 oz shell with a 7 or 6 ounce end plug. One should also be able to generate more bat speed with this type of bat because of the larger difference in shell weight and end load when compared to a warranty bat.

These are bats that over 99% of the softball players in the country will never see or use unless they play on a major team or have a friend playing for a major team and can get one. The wall thickness of these bats are so thin that they can't even be classified as no-warranty because they can literally cave in on the very first swing. These bats fall well below the 0.069" wall thickness that the no-warranty bats have. One bat that we tested was an amazing 0.056" wall thickness and looked just like a triangle, the result of 2 good swings. The reason you see the super players hitting those 400'+ bombs is twofold, they definitely have the strength and ability to do it and they can maximize their hitting distance by using these hyper-thin walled bats. There is almost no limit in terms of distance that these bats can generate. These bats are considered throw-away bats and do not last more than a few swings each. That is why some super players go through several bats a weekend. A typical 29oz Super Player bat can have a 9 or even 10 ounce end plug on it with shell weights as light as 19 or 20 ounces. The bat speed that can be generated with such an end loaded bat is amazing!!! However, the rules are changing this year and the super players must use bats that have a 1.20BPF stamped on them in all USSSA major tournaments. 

This article was written to make other players aware of the differences between the wall thickness of aluminum bats and address why there is so much hype surrounding the thin walled bats. It also gives the reader something to think about the next time they shell out the extra money for a no-warranty bat or (so-called) advanced player bat.

In summary, the thinner the wall, the farther the ball travels is definitely true. This is due to two factors, the thin wall increases the trampoline effect of the bat and the reduced shell weight combined with the extreme end load tends to increase bat speed. The down side is that it will cost you a substantial amount of money to maintain such a bat in your arsenal. However, we believe that for the best compromise in terms of cost, durability, and performance a warranty C405™ bat is the best way to go.