Category Archives: Technology
The World Headquarters of Racquet Quest was pleased to have Erika and Federic from Head visit recently. Erika is with Head in Phoenix and Frederic is from the Headquarters in Kennelbach, Austria.
Team Head player, Jack Anthrop was on hand to provide a players perspective.
The purpose of the visit was to discuss a “grassroots” program that can effectively address, and contribute to the growth of tennis worldwide.
I was commenting on racquets and string selections, of course, when it dawned on me that Head has done an extraordinary job in designing racquets that have vast player appeal! A prime example is the Adaptive Series, introduced about a year ago, consisting of a “Speed” and “Instinct” model.
This series can go from a lightweight standard length racquet to a more substantial, longer racquet in a few minutes! Plus this series can be either a 16 x 19 or a 16x 16 string pattern!
This concept is valid, and one that allows players to maximise the performance of the racquet. And the implementation is easy. Some changes can be made at courtside!
So, while I believe more can be done to get players into the correct racquet, the Head Adaptive Series is very close to being perfect!
A lot of players are anxious for new tennis racquets this time of year and have, maybe, asked for one as a gift. A great idea, of course.
However, be sure the gift giver, or yourself, gets real! There are some real bargains out there, but the bargains may not get you what you expect. This can happen to any brand and the more popular the racquet, the more likely there are to be fakes!
This is an image of a fake Wilson Blade 98 compared to a real Wilson Blade 98.
I am showing this image because without seeing this detail the fake racquet graphics will look nearly identical to the real Wilson racquet.
One of the best ways to confirm a fake or real racquet is to “bend” it, that is to check the stiffness of the racquet. In almost every case the fake will be quite a bit more flexible. For example, this fake racquet has a stiffness of RDC 41 whereas the real racquet has a stiffness of RDC 63. If your racquet technician does not have a device for checking stiffness the next best thing is to look at the “insides.” A qualified racquet technician will know what the insides of the real racquet look like.
Another sign of fakery is the grip pallet. Most performance racquets will have a foam pallet molded over the graphite shaft or a two-piece pallet that is attached to the racquet shaft.
Fake racquets may very likely have a continuous graphite pallet. You can quickly look under the first couple of inches of the grip and see if it is foam or graphite.
Clamshell grip pallet
If you are requesting a new tennis racquet be sure you get it from a local business, if possible, or an otherwise reputable source.
If you have any questions at all, please call your local dealer or us (407.491.4755) to be sure you “GET REAL.”
It seems like Ashaway had this very racquet in mind when they developed their Dynamite Soft 18 string! This blue string is a perfect match to the blue accent color on the Ultra 100 CV and Ultra Tour!
And, the gauge, a very thin 18, is a perfect match to the very stiff frame (73 RDC, 70 FF stiffness).
I think the 18 gauge string may not be durable enough for hard hitters but this combination could be very good for many players.
You can be the judge of that, of course.
The string tension of 48 lbs (21.7 kg) combined with the racquet stiffness returns an effective stiffness of 30.3 which is a very comfortable number.
This stiff, 100 square inch racquet, should pack a powerful punch with a weight of 318 gr (11.2 oz) and swing weight of 318 kg/cm^ (11.2 oz).
I have been working on these new models for a few days and will post more data as it is available but right now here a few points about this fascinating racquet concept.
The two (2) models are Speed Adaptive and Instinct Adaptive. The racquets are both new versions of the current models with slightly newer graphics, that are, in my opinion very cool! The Instinct has new graphics which will appeal to more players.
First, the Adaptive Tuning can create thirty-two (32) possible combinations, including increasing the overall length of the racquet.
The racquets are shipped in the lightest (285 gram), 16×19, 27.0-inch length format, and swing weight 287.
The Adaptive Tuning Kit is required and costs $29.00. In the “kit” you will find a “heavy” butt cap insert, three (3) sets of grommet inserts to add weight and change string pattern, and three (3) sleeves that go onto the shaft to create length.
The length modification can be made quickly by the player, if necessary, however, the other modifications require the racquet to be unstrung.
These modifications should be left to your racquet technician.
Below is a spreadsheet representing the various combinations as they are applied. This does not include all the options because the 16×16 grommet set did not participate in this session.
This was done at Racquet Quest, LLC and represents actual data, not calculated characteristics.
What is “soft”?
In 1994 I did a presentation for the USRSA in Atlanta. What was the topic?
It is now 2016 and we are still trying to understand string! Especially “soft” polyester based string.
In 1994 PolyStar was the only polyester based string I was familiar with. Since then there are dozens of offerings from anyone that can afford to purchase from manufacturers and market the string. If you have a desire to do it I applaud you!
In 1989 I started testing string and calculating “power potential”. Why “power potential”? Because “modulus”, “elongation” and “elasticity” didn’t get to the bottom line of string performance quickly enough! The steps to arrive at power potential are many.
For the testing, several calculations take place including “stretching” the string as in a ball impact. The difference between the first calculation and the “stretched” calculation is the power potential!
I have calculated hundreds of power potentials but have not until now quantified “soft”.
I think now is the time!
Dr. Rich Zarda has done a tremendous amount of work on this issue so we can now distill this work into the following explanation.
So, what is a “soft” tennis string?
Strings in a tennis racquet carry the ball impact load in two ways:
1) Via the pre-load string tension placed in the strings caused by a stringing machine (and the racquet frame “holding” those tensions in place) and
2) Via additional tensions that develop in the same string caused by the elongation of the strings as they deflect with ball impact.
Both of these conditions occur simultaneously and contribute to the string bed stiffness (SBS, units of lbs./in). Racquet technicians measure SBS by applying a load to the center of a supported string bed and measuring the resulting deflection. Dividing the load by the deflection provides the SBS (lbs./in). The lower the SBS, the more power you have (power here is the ability of the ball to easily rebound from the string bed), but the less control (presumably); the higher the SBS, the less power you have but the more control you have (presumably).
One more point about SBS: the lower the SBS, the less the load your body will feel for a given swing. But for an SBS too low (less than 50-80 lbs./in), balls will be flying off your racquet going over the fence; and for an SBS too high (greater than 200-240 lbs./in), the racquet will hit like a board with significantly less ball rebound. So the most common SBSs are between 100-200 lbs./in: a balance between control and power.
As already expressed, SBS is a function of the pulled string tension and the string elongation. Here is what is interesting: For large string elongations (for example, greater than 15%) and reasonably pulled string tensions (greater than 30-40 lbs.), SBS only depends on the pulled string tension and it does not depend on string elongation. Additionally, for this condition, SBS, for these high elongation strings, does not change as a ball is hit with more impact.
But for a string bed with low elongation strings (less than 5%) under low pulled tensions (less than 20 lbs., or tensions that have been reduced due to racquet deformation and/or string tension relaxing with time), the SBS additionally depends on the string elongation and will significantly increase, in a nonlinear ever-increasing way, for harder ball impacts.
In order to achieve a repetitive feel for a player when hitting with a racquet, it is best to have a SBS that is independent of an increasing ball impact force. This will lead to a more consistent playability of the racquet, which includes a more repetitive feel. This desired “feel” implies using high elongation strings (greater than 10%). If low elongation strings are used (less than 4%), the SBS will significantly increase as the ball impact force increases, resulting in a racquet feeling “boardy” for higher impact loads. And low elongation strings will cause un-proportionally increasing load into the body.
As you can see by the graph, elongation contributes to SBS in a big way. The red line indicates a stiff string, about 4%, and the blue line indicates a “soft” string, about 15% elongation. You can see the loads increase dramatically as the impact increases. So the harder the hit the higher the loads on the body.
So to the question asked at the start “What is a soft tennis string?” In the context of the SBS discussed above, I would suggest that a soft tennis string is one whose elongation is 10-15%, and a stiff tennis string is 4-6%. And any string under 4% should be categorized as ultra-stiff.
String elongation (soft, stiff, ultra-stiff), stringing machine strung tension, and string pattern(s) all contribute to SBS and SBS is an important measure of how a racquet plays and should be adjusted for an individual player, stiff and ultra-stiff strings can lead to less-repeatable racquet performance and player injury.
Soft = 10 -15% Elongation Power Potential Range = 10.0 – 16.0
Stiff = 4 – 6% Elongation Power Potential Range = 4.0 – 7.0
Ultra Stiff = Less than 4% Power Potential Range = .65 – 3.96
Racquet Quest, LLC, with the help of Dr. Rich Zarda and myself, invite you to meet us at the World Headquarter’s of Racquet Quest, LLC on Thursday, October 20th at 7:00 PM for an open discussion on tennis racquets, and, strings technologies. We expect to finish no later than 9:00 PM.
This first discussion is open to the first twenty (20) that respond, and, are attending. If this discussion is worthwhile, we plan on supporting larger groups in the future.
Racquet Quest, LLC is located at 3490 US 17-92, Casselberry, FL 32707, directly across from the Home Depot. You can find directions at www.racquetquest.com.
This is a “discussion” not a “sales” meeting, so your questions are solicited. If you want to send your question to me, email@example.com before the meeting date, please do so.
We will answer any prior questions at the discussion so everyone in attendance will hear the same answer.
Light refreshments will be served.
We look forward to seeing you here! Please RSVP with a phone number and/or email address. Time and space is limited.
Thank you for your interest…
Building a “custom” racquet is exciting not only because of the work involved but from the “joy” of the finished product!
When I receive racquets similar to the state shown the first thing that happens is numbering and characterization so it can be tracked throughout the process.
The first piece of equipment I use is the Ereca Balance System. Here is why. The two (2) scale system is fast and extremely accurate. This first “pass” tells me how much work is required to get the racquets to the customers specification.
These racquets had an average deviation of 1.69 grams! Other specs were also very close. Knowing this when I start the process means I can pick almost any of the racquets with confidence that I can achieve the desired “finished” specifications.
As you know I insist on swing weight as a major racquet property but this system gets me off to a great start and saves considerable time.
Each client has a specific specification they want in terms of length, swing weight, overall weight, grip size, grip material and where any modifying material, if required, will be added.
Adding string is a big factor because of the different weights of various string. Stringing is, typically, the final step in customization if any material is under the bumper guard
Custom racquets are not only fun to build they are fun to play with!
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…
Racquet Quest is in the racquet technology business! What does that even mean?
It means we devote a great deal of our time to understanding racquets and what makes them ”tick”. Of course, it is fun and meaningful but sometimes not well understood.
Hardly a week goes by that I don’t have a request for “Pro Stock” racquets of some sort. But what does that mean?
To help sort out this question I reached out to one of the people in this industry that knows the answer! Jerry, I will call him, works for a major racquet manufacturer and is responsible for racquets for professional players. I asked him to comment on the following narrative. The responses are in red.
Pro Stock Racquets. What does that even mean?
“Rackets which have been customized to players need.”
“Many people believe that pro players are using different construction, which is actually not true; a reason to think so is that these people have no idea about racket production.”
For years, it has been the position of manufacturers that the “retail” version of racquets did not work for the top world ranked player(s). So what to do?
“Players need different weight/balance/swing weight than regular players due to their fitness and technique.”
Many “pro” players prefer the model they started their career with but those racquets have long been replaced by newer, and mostly, better technology regarding materials. Of course, it is “possible” to use the older mold, (the mold is not the graphite tube), to re-create the preferred geometry and feel. I doubt that the materials I used in our racquets many years ago are still available.
“If players are used to their old/first racket as their extension of the arm/hand in many cases they don´t want to switch unless they feel they have to!”
Probably the most important consideration is the third paragraph. “Players need different weight/balance/swing weight than regular players due to their fitness and technique.” Why would I even think I can play with the “same” racquet as Roger, Novak, Andy, Rafa, and the rest of the top players! It is simply not possible.
Yesterday I finished an “evaluation” racquet for a pro player with a swing weight of 400 kg/cm2 with an “even” balance. Is this a “pro stock” racquet, or just a racquet that has been radically customized?
I can, however, make my racquet the best it can be for ME! So, let’s go back to the top of the page,“Rackets which have been customized to players need.”
It doesn’t matter to me at what level you play but as racquet “technoligsts” we can help you be a better player.
Well, I made it to see 2016 arrive! I am not sure why I stayed up but it does commit me to pay attention to what may happen in the coming year.
I think the big story for 2016 is going to be more string related than racquet related. Why? Because manufacturers can “turn around” a string model much quicker than a racquet model, and, there are significant areas for improvement in selecting the correct string material for each player physicality and style.
String characteristics, materials, tensions, and applications are confusing to many and rightly so. This year I want to continue the “educational” effort and invite anyone with something to contribute to speak up.
My motto for 2016 is “Speak Up…Then String Up”