Warped Hoop - Head Gravity

The recently launched Head Gravity series of tennis rackets are really soft and arm friendly. 

This rare flex got many players on board, especially previous users of the Babolat Pure Drives and Aero Pros.

However, their feedback has been mixed. Some loved the Gravity while many others hated its inconsistency and lack of accuracy.

In stock form, I find the power and stability lacking.

However, it is the incredibly soft hoop that poses the biggest problems. It is almost as soft as the old but very popular Head Prestige.

Maintaining hoop shape while stringing this Gravity is challenging. I received so many badly warped hoops that rendered the racket unplayable.

Take a look yourself at the three videos below...

The stringjob in this first video was done by another stringer. You can see the Head logo stenciled. The hoop was approximately 24.8cm wide.

In the second video below, the hoop width was approximately 25.3cm after the strings were cut and removed.

 

 
The third video showed the width to be almost exactly 25.3cm after I restrung it. No stencil. Almost zero distortion.

Naturally, the player loved the distortion free stringjob.

If you have a Head Gravity playing inconsistently, it could be the stringing. Try measuring the hoop width without and with strings.

PS: Sorry about the lousy video quality...somehow it deteriorated after uploading
 



   

Warped Hoop - Wilson Blade 104 (2013)

Almost all soft hoops rackets sent in to me were strung warped by their stringers.

This Blade 104 has a very soft flex of RA59.

The one with red strings was strung by me about a week ago. The one with black strings was strung by something else. 

The one with black strings has its hoop widened by 5mm. That is a lot!

Both rackets inside hoop width were 26.1cm when strings were cut.

Videos below...

    

Wilson Clash Customization

The latest Wilson Clash seemed interesting. 

Marketing generated so much hype that even during pre-launch in late 2018, I received many questions from players about its potential to up their game.

It did not take long before both versions were sent in to me for stringing and modifications.

I had a few hits with some that were sent to me strung. Surprisingly, many were strung with poly/multi or full multi. Few were with full poly. 

Dampener or not, the feel was very muted yet included a lot of buzz and trembling. This felt exactly like "hoop wobble" (link). Immediately, this hinted a potentially very soft hoop. Extra care needed when stringing. 

When lacing up the centre main, what struck me was how big the modern grommet holes were. Every hole was large enough to be a tie-off hole. That made threading strings very easy.

My earlier suspicions were confirmed when tensioning the mains. Previous soft hoops I worked on warped more when outer mains like 6, 7 or 8 were tensioned. The Clash started warping significantly from inner mains like 3, 4 and 5. That is a very significant change and carries huge implications.

Crosses start very high and have smaller gaps near 12 o'clock. These gaps almost double near the last few bottom crosses. Another hint of potential erratic stringbed response especially nearer the top quarter or top third which most professional players like to contact the ball at.

When weaving the crosses, the gaps kept reminding me of the earlier Burn series. It was so wide it created control issues for many. And those that could somehow control the ball snapped strings too quickly. Would this happen with the Clash open gaps? (I was later updated by several their strings notched extra fast in the Clash compared to their own 16x19 stringbeds)

As I examined the throat area, I noticed a notched recessed area inside the throat. (Somewhere beside the "o" and "n" of the red "Wilson" wordings) This must be where the racket is flexing on impact. Interesting. Few rackets I can think of, other than wood, flex at such a low and faraway point away from impact point.

Not long after, another Clash came in. Brand new unstrung. For very heavy customizations for a touring professional.

Armed with the feedback from the earlier few Clashes, I took up the challenge. 

It was a challenge because the Clash was marketed as a very powerful frame. Many complained of timing issues and erratic hot spots on the stringbed. And it had very open strings coupled with a very soft flex of about 55. All these pointed to control issues.

To add power or weight meant doubling up on these control problems.

Nevertheless, I did the calculations and it all added up nicely. So I proceeded.

First step, strip the grommets.

Now that you see how much lead tape I am adding, can you understand why I said it was a challenge to add control and keep the ball in? For a professional full time tennis player!

(I scribbled on the lead tape too!)

Grommet installation was very very easy. Took me about 4 seconds. Fastest I have ever reinstalled top grommets after adding lead tape.

For this ease of reinstallation, I have to thank Wilson for this modern grommet design. The centre pieces always cause the biggest obstructions. So they cleverly separated the centre 10 grommets from the bumper guard. And the drilling featured extra large holes for easy grommet installation. Well done Wilson!! And thank you!!

Typical of a new unstrung before racket, the grommets need to be seated properly to ensure a playable string job. Look at the red circles area below, compare the properly seated grommet with the "unseated" one.

Do not assume this happens automatically when you pull tension. I have several strung frames sent in to me with the grommets still "unseated".
 

Until now I do not understand why so many are enamored and mesmerized by silicone in the butt. Everyone I customize for asked for it!

Final checks before handing the frame over to the player. So far the hoop size QC seems very consistent. All Clash and Clash Tour I worked on measured 326mm length and 251mm width for the inside hoop from base of grommet to base of grommet. Zero hoop distortion achieved.

PS: No details of racket weights, specs nor string tensions would be revealed as these players are still actively competing. So please do not ask. 






    

A Warped Vantage Custom

A ranked tour player, RK, whom I have been working with for the past two and a half years, encountered a rare string snap during a multi-leg multi-country tour.

Down to only one racket, RK decided to send in his stick to the tournament stringer. Something he rarely does.

It was strung alright. As in the strings were filled, weaved properly, tensioned and tied-off. However, he felt it was unplayable. It was his racket indeed but somehow he could not play with it.

Everything felt wrong - feel, sweet spot size/location, stability, accuracy, control and power. His usual serve and volley game fell apart completely. He could not serve with confidence. He could not volley.

Left without any choice, RK relegated that freshly strung stick to be a backup racket of last resort.

And continued using the other racket I had strung for all practices and matches, singles and doubles, for the remaining legs of his tour!

RK was kind enough to withhold this from me until his return to Singapore. I was absolutely stunned and speechless when I heard it!!!

Then he handed me the "odd" racket. The one with green strings. Yes, it was warped. Hoop was compressed 3mm.

In the last post on the Head Prestige S, I had problems with parallax error in the pics. 

So this time, I took two short video clips of the warped Vantage racket. One strung. The other with strings cut. The above two pics were screen prints obtained from the two video clips.

Please watch the two videos below and decide for yourself if the hoop warp was acceptable.

Below video with strings intact

Below video with strings cut

Apologies for the upside down video. Not sure why or how it happened :)




     

Another Warped Head Prestige...

A chap I met recently named "MB" asked me to restring two Head Graphene Prestige S.

When MB first handed me the rackets, I immediately noticed how warped the hoops were. (Link)

The Head Prestige series have very soft hoops. That contributes their signature feel and flex. However, this soft hoop also makes it very challenging to tension properly while maintaining the hoop shape.

When strung wrongly, the hoop narrows and racket length lengthens. This greatly reduces the sweet spot size and also "shifts" the sweet spot downwards nearer the handle.

What one feels with a wrongly strung Prestige is what I would deem "hoop wobble" - a combination of vibrations and frame twisting mixed together during ball impact. 

The racket also becomes very difficult to play with, and almost impossible to volley with.

When tensioned and strung well, the entire frame is very smooth and quiet. The hoop is incredibly stable and the true flex of the racket at the throat area surfaces. An incredibly sweet and addictive frame to play with!

I'll let the pics below do the talking. Note there is some parallax error in the pics. The correct readings are written in blue...

Below pics from racket #1, with snapped old strings, cut out old strings and newly strung, respectively from left to right.

Below pics from racket #2, with old strings intact, cut out old strings and newly strung, respectively from left to right.

Below pics shows a side by side comparison of the hoop shape and width of racket #1 freshly strung (left) and #2 with old strings (right). Even with the naked eye, the discrepancy is visible.

Sometimes when choosing rackets, the challenge is not just whether one can handle the frame. You need to take into consideration if your stringer can string the frame properly too.