Natural, Slugs, Interchangeable... What does your thumb desire...

Traditional slug

One of the keys in bowling is consistency. As part of that foundation, the feel of the thumb coming out directly impacts each roll of the ball. As the industry has matured we have come from conventional drills all the way to interchangeable thumb inserts in a short amount of time. Just like many other sports, technology has made a direct impact on how the game is played and opened up options for the people playing it. Bowling is no different. Now there are several other things to take into consideration, but my focus today is as I said before... thumbs. Now, we all know about the conventional drill. That is where you just punch down a ball, bevel the edges, and hand it to the bowler and let them rock. Now, this isn't to say that it is only for beginners. There are quite a few bowlers, even on the PBA Tour, that are more than comfortable with a natural feel in the ball. Also, it really is a bit more involved than just making a hole if you consider pitches and ovals, but that is for another conversation. However, with this type of drill, you present two different materials that make contact with your thumb. The coverstock of the ball and then slightly deeper, the fill material in between the cover and the weight block. For some bowlers, this causes an inconsistent feel at the point of release. Where you might snag your thumb and stick in the ball. To resolve this, enter the slug. Thumb slugs are typically made of vinyl or urethane. What this enables is a even release of your thumb out of the ball due to the material in contact with your skin being the same all the way down the hole. This is probably the most common type of thumb you will find on the lanes. From beginners to pros, it is a relatively inexpensive and easy way to achieve that smooth release from the ball. Taking this technology a step further, you can also cast molds of your favorite thumb drill so that it can be recreated over and over again. One of the more popular system, being the Custom Thumb, almost alleviates the 'this ball feel different' syndrome, which we all have experienced if you have more than one ball. In addition to the stability it brings to the game, those of you that are keen on looking good can chose from just about the entire color spectrum to use. Flash on with your bad self!

Thom Thumb

Now we move on to the interchangeable breed of thumbs. This allows the bowler to have the same exact thumb in every single ball. Also, it allows you to carry different sizes of thumbs based on swelling instead of having to mess with tape or any residue left behind when you remove it. The birth of this idea goes back quite a way to a system called Thom Thumb.
Although short lived and the company is out of business now, it really spurred the industry in the right direction when it comes to customizing the fit and feel of a ball. Using an inner and outer sleeve design, it worked, but wasn't really adopted by the masses. The next company to step into the space was GripLoc. Their system used was a bit different. It leveraged an outer sleeve and a quarter turn pre-drilled insert. Later they offered blank slugs that were keyed to fit in the outer sleeve, to allow for further customization. Although the GripLoc system is still offered today, it is not near as popular as the two companies that have dominated the changeable thumb market.

GripLoc

Not surprisingly, the lion's share of usage is represented by long time insert makers Turbo and VISE.  The Turbo's Switch-Grip consists of a two piece, inner and outer sleeve system, that interlocks into the ball similar to it's ancestor from Thom Thumb. In the case of Switch-Grips, you can use a normal slug inside the inner sleeve, further expanding it's customization and consistency of feel. Turbo has even taken this technology one step further and created an identical system for interchangeable finger inserts as well, but we will save that conversation for another time. Finally we have the VISE IT system. Instead of a locking system that all of the other manufactures use, VISE has opted for a 'screw' in process of securing the insert into the ball. The entire system is based off of a top outer sleeve, a threaded base that goes in the bottom of the thumb hole, and a threaded base that is attached to the slug. This allows for a super tight fight that will not budge when locked into place.

Turbo Switch-Grip

Here it comes, addressing the question that is burning in your mind... which is the right one for me. I will start by saying I have tried them all. It boils down to the application, how you bowl, and how much you want to invest in your game. If you are a beginning bowler, just out there shooting recreational games, going without a slug would probably suit you just fine. Stepping up from there, for plastic equipment or spare balls, going with a slug is the best bet. No need to invest in an interchangeable system that might end up being about 80% the price of the ball you are putting it in. Now when looking into interchangeable thumbs, there are a few things to consider. I have heard some high rev rate bowlers complain about breaking Switch-Grips early on when they hit the market. Since then, Turbo has invested quite a bit of money into developing a much more robust locking point and that issue is no more. You can visually see how much more beefed up they are. With that in mind, I haven't heard of anything breaking when really ripping out of the ball when using the VISE system. I can't speak to any of them breaking personally, probably because my rev rate is more human than beast so it's not like I am going to stress the locking mechanisms at the point of release. However, I can speak to them being tough as hell when dropped, kicked, or even thrown. And let me tell you, it wasn't me that lost my cool, but those little buggers are hard to dodge when someone is upset enough to sail them across a center. The second thing to consider is if you have a very particular feel and are sensitive to swelling and shrinking of your thumb due to number of games you have rolled or weather. This eliminates the worry of fighting with your thumb hole using tape or powders when armed with a couple of different fits that you can just change over to. Lastly, the cost. They do cost money to get into, but once you have your one or two thumbs, it's all sleeves from there. So in the long run, if you have quite a bit of equipment or you tend to buy several balls a year, I would say go for it. You won't be disappointed.

VISE IT

Now for my personal experiences. I can't really recommend the GripLoc system. Although it wasn't any one thing that turned me off or anything truly negative happening to me with them, they just didn't feel firm at the point of release for me. I also noticed that the pins that lock the thumb into place wore down and rounded a bit from changing them in and out over time. Now, Turbo and VISE have been absolutely solid for me. Matter of fact it is a real toss up on which I like more. From a useability perspective, they are both easy to use and they are both very solid when locked in. For me it came down to simply which I had more of, which was Switch-Grip. I have no problems at all recommending both to anyone who asks. I also carry both inserts so that I can show the differences in the two systems when I get asked about what I use. So if you are looking to create a consistent feel across your arsenal, as a rule of 'thumb' (no pun intended), I say give Turbo and VISE a hard long look. Also, talk to your local pro on what they recommend. They are your eyes and ears for what people are buying and using, leverage that free information to make a complete and informed decision.