Category Archives: Testing Devices
It is easy for me to post pictures of racquets being made ready for shipment to tournament players. However, there is a lot more work before these can be tagged, bagged and packed!
Paperwork is what I am talking about! I have included some of the paperwork in this image, so you get some idea of what is involved. Not many people like paperwork but for this work it is essential!
Every racquet we do has the same “paperwork”, but local customers normally don’t need racquets customized and shipped overnight! Out of town customers, your racquets are typically prepared as close to the “use by” date as possible. So these racquets were strung and tweaked this morning and shipped (via overnight) this afternoon. Most of the customization can be accomplished before stringing but final adjustments, if required, are the last thing on the list.
The “paper work” on the right is data from the ERECA Balance System, and this information is taken at each step in the customization, and at a “play ready” status. While I still rely on swing weight as the primary dynamic property I use the ERECA system for very precise static balance, total weight, and a quickly calculated swing weight.
The other “paper” is my standard Racquet Record software data that contains over forty (40) pieces of data that are a permanent record in the customer file.
It sounds like a lot of paperwork, but it is necessary to assure consistency and organization. Every racquet gets the same treatment.
So, the next time you see pictures remember there is a lot more to it than stringing, bagging, and shipping.
I am very happy to have Eric Ferrazzi of Ereca Tennis visiting Racquet Quest!
Eric designs diagnostic equipment for technical tennis shops. Racquet Quest has been using some of the Ereca designs for several months with great success and acquiring better data.
It is important for us to recognize what we can do with proper equipment, and, take advantage of the technical designs of the Ereca Team.
Ereca has many other designs that are in the “evaluation process” and Racquet Quest is happy to be involved!
Now if Eric could just teach me how to cook French food…
First let me get the “shorts” thing out of the way…I like them! I would like them better with a cool white shirt, but that’s just me.
The next item of business, for me, is the fantastic one hand backhand that serves Stan so well. It makes me wonder why juniors, and maybe some adults, are being taught (forced?) the two hand backhand?
I think I understand the physics invloved in swinging a racquet and I also understand that you can build muscle memory and pure muscle if you train for that (one hand backhand).
After seeing the effectiveness of the one hander it seems more players would request that technique be taught to them.
I am still in Italy but will be headed back to France in the morning to continue discussions with Eric and Carine of ERECA regarding diagnostic devices and some ancillary equipment.
SBS is “String Bed Stiffness” and is the stiffness of the entire strung area of a tennis racquet. SBS is not the same as “tension” and this is important to understand. Why?
When you talk to your racquet technician about “tension” it is, normally, about what number to set on the stringing machine. This number is usually called “reference tension” and every stringing machine has a way to set how many pounds, or kilo’s, it will pull each string before it stops.
Here is the problem with “reference tension”. It means different things to different machines! A “reference tension” of 55 pounds will result in a different SBS when set on different machines. If you take your racquet to technician “A” who uses a lockout machine it will have a different SBS than technician “B” that uses a constant pull machine . Over time, perhaps, each technician will arrive at the perfect machine setting to satisfy your requirements.
Why do all of this? You need to request a SBS! When talking to your technician you will talk about resultant SBS. So each time you have the racquet strung it will have the same SBS regardless of what machine it is strung on. The SBS number will be based on the diagnostic device the technician uses to collect data. There are three (3) or four (4) devices that will be familiar to all technicians:
The two Beer’s devices will return virtually the same number since they use the same technology.
The Babolat RDC uses, as far as I can determine, a combination of deflection and voltage. The FlexFour uses a deflection and includes the racquet stiffness..
So, the numbers may be different but it is the variation between tests that are crucial. If you are serious about your SBS I suggest you get a Beer’s ERT300 (about $180.00) and keep it in your bag. If the racquet has a SBS of 41 right after stringing you should consider having it strung when the SBS has decreased to about 33. For any device you should consider a reduction of twenty (20%) percent a reminder to have the racquet strung, soon!
SBS is String Bed Stiffness. What this tells us is the “stiffness” of the entire string bed, not just a single string. You may still hear the term ASPS, Absolute String Plane Stiffness, but that is too many words. How is this different than “reference tension”? Reference tension is the number you, the customer, tell your stringer to set the stringing machine to pull each string.
This “reference tension” has been the default conversation between customer and racquet technician for many years. The problem is that the SBS may not be even close to that number so as a racquet technician we need to know what the SBS is at a given “reference tension”. A device such as the Babolat RDC shown above can do this but it comes at a hefty price. The Beers ERT300 is
an electronic device that is available for around $150.00 and gives a number in Kg/cm, which can be easily converted to pounds. The FlexFour is another device that returns valuable SBS numbers. The point is be sure your racquet technician is using some device to record SBS. At Racquet Quest we use all three (3) so we can respond to any SBS request.
Without going into what happens to a string and racquet during the install process it is clear that the ball feels the “result” of all the strings acting in concert with one another and the racquet itself. So it makes sense to know what SBS (stiffness) the ball is “feeling”, and with this SBS number and the racquet stiffness number the “effective stiffness” can be calculated. Through manipulation of the SBS a “perfect” effective stiffness can be provided to you the customer.
So when you hear the term SBS you can quickly join the conversation and know what you are talking about! And, that is a good thing!
I just returned from SanDiego, CA where Tim Strawn and I met with the StringThing™ team. A really good group of guys! Dave, Scott, Stephen, Mike, Steve, and Dr. Norman made us feel like part of the group!
We went to the manufacturing facility (yes, it is the United States!) and it is impressive in terms of taking an idea from concept to market in the short period of time they have done it.
These are tennis players, each and everyone! They enjoy the sport and it shows in their commitment to this product.
You may have seen my short video on the String Thing™ and there may be other video coming soon. If you have not seen the video please take a look. I believe this product is a good one so I wanted to take the trip to SanDiego to meet the people.
If you have any questions about the String Thing™ please let me know.
The String Thing™ is designed to re-align strings that are out of position.
I have been using the String Thing™ for a few months and wanted to post this short video for those that have questions about how to use it.
Please let me know if you have any questions.
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There must be hundreds of web sites and forums that discuss tennis and tennis racquets specifically.
Racquet Quest is different…
I have spent over forty (40) years working with racquets; from designing to manufacturing to stringing to customization, plus retail and anything in between! I know that each racquet and player combination is unique. So, the racquet specifications must be exclusive to the player.
Even if you go no further into this site I want you to know that you, the player, is what this is all about. Some fun, some ideas, some questions, some suggestions, and most importantly, your involvement.
I hope you will enjoy your visit!
Do you like the strings in your racquet to be straight? Well, most players do. Until now it has been a “digital” operation, that is you used your fingers to bring the strings back in line!
Now there is the String Thing™ to help you out. The String Thing™ appears to be a durable device that holds two (2) rows of “teeth” that straddle the string and when moved up and down the string will embed in the string openings and align them. It is not quite perfect alignment but it is much better than using the digital method, in my opinion.
I tried my best to see if I could damage the string either by sharp edges or operator error and was not successful! The alignment teeth are mounted in such a way that allows them not only to rotate but to move from side to side. This should eliminate any hard contact with the string along the sides.
For most players this device will perform as expected and for only $19.95 plus shipping represents a good value, I think. I purchased mine and paid $4.95 for shipping.
I suggest you get one and let me, and others, know what you think!
Since I posted this a lot of you want to order so here is the information I used: www.stringthingusa.com
Most racquet technicians are familiar with the Stringmeter device. The Stringmeter uses a torsion spring to measure the tension on a given string. It has three (3) modes; stringers free string scale, Kg scale for strung racquet, and Lbs scale for strung racquet, with a string gauge scale for 15, 16, and 17 gauge string. Sounds simple enough, right?
Sure, but the Stringmeter is probably the most misunderstood device known to man, or in this case racquet technicians. Why? Simple. What does the number mean and how do you keep it a secret from your customer! One thing at a time, please. First, the string is inserted between two posts on the underside and the device is rotated until the string is aligned in the string gauge slot. Simply read the number on the gauge and that’s it. This number is accurate and indicates the tension in that specific string. Why would you want to keep this a secret from your customer? Because it is probably not going to match the tension the customer asked for. You could explain it but that may not satisfy the customers curiosity.
More about this later but let me tell you how I use the Stringmeter and why it is the only device that does what I need. When I evaluate a stringing machine one of the most useful pieces of information is how much tension is left in the string with only the main strings in the racquet. With only the main strings in the racquet I find that most machines will allow the racquet to distort considerably, simply get wider, allowing the string tension to disappear.
So, each string is measured with the Stringmeter and this is recorded. But wait! Recently I was comparing numbers with my colleague and was surprised when there was a huge variance between his numbers and mine. He sent me his Stringmeter and it was instantly obvious what was wrong. His Stringmeter had been re-designed to make the tested number be more acceptable to the racquet technician and the customer! So now instead of the Stringmeter reading “0” when there is no tension on it, it now reads “17”, or thereabout, with no tension on it!
So, for my purposes the new Stringmeter is no longer valid.
Now back to the good stuff. The Stringmeter, even the new design, can be used as a reference tool to measure tension loss over time. Check the tension in the same location and be sure you are exact in the location of the string in the gauge slot. When checking the cross string you will notice a big difference in tension relative to the main string. Many say, and believe, this is a function of friction between the main and cross string during installation. Nope. This difference is because the racquet has distorted and has used the cross string tension to “pull” the racquet back into shape.
I will continue to use my “old” Stringmeter for my specific purpose but I would suggest any racquet technician invest in a device that removes any operator influence. The Beers ERT300 is a good, portable, inexpensive (relatively) device that returns a string bed stiffness not an individual string tension.