Yamaha Secret 04

[nat75]

Continuing the Japanese theme...

Here is a Yamaha EX-110g. I own and have played quite a bit with one of these. It has a box-beam and is more muted and lower powered than the EX-110. It's my favourite Yamaha.

Gaby played with this racket for a short period pre-retirement.

 

[FedererClone]

Gaby played with this racket for a short period pre-retirement.

Gabriella Sabatini?

 

[Virginia]

There's only one Gaby!

 

[nat75]

Gabriella Sabatini?

Yep.

 

[schu47]

The 04, 06 and 10. Same mold, but very different racquets, IMO. All are heavy, stiff frames, but the 04 is much more so than the other two.

IMO, the 04 is a one-of-a-kind powerhouse -- I've never swung another racquet quite like it for controllable power. The 06 and 10 are just average frames, at least that's what they seem to me.

 

[FedererClone]

Gabriella Sabatini?

Yep.

ah, those legs..... loved watching her play. Same with Mauresmo today, but it looks like she's retiring....

 

[gkenney]

I've played the Yamaha Secret 04 and 06 since the late 80's to the present (2020) and more recently the EX. I've temporarily played other racquets such as Prince and Wilson but I'm always happy when I put the Yamaha Secrets back in my palm. I've never been a great tennis player; leveling off at 4.0 and no more. There has never been any serious tennis elbow or wrist problems using these racquets. Quite honestly, the 04 and 06 feel similar to me except for the 04 feeling more dead on off center strikes. It's quite possible I just don't have the feel or touch better players have that allow them to distinguish the difference. The EX is a fun racquet but shouldn't be cut out into the same corral as the other two. I'm now in my mid-60's, I only play doubles, hit heavy forehand topspin from the baseline, a flat drive from my one arm backhand, driving slice approach off both sides (some actually go over the net and stay in play), marginal and undependable drop shots, reasonable volleys but nothing spectacular, etc.

I have a stash of these racquets and recently had to send an 06 to the dump after it cracked at the head. It was a solemn ceremony of one old timer bidding farewell to another. I'm stocky, have compact strokes and a fair amount of muscle mass in my arms, back and legs. I string my own racquets with 17ga mains at 56lbs and 18ga crosses at 58lbs. Any discomfort I ever felt with these racquets disappeared with thinner gauge strings. It may be my build and swing mechanics (or lack of nerve endings) saved me from the joint pain others have experienced.

Someday my stash will run out and I will need to move on or I'll blow out one of my wheels and tennis will be in my past but as long as I'm playing and have my stash I'll stay true to this classic.

 

[gkenney]

The following tabulation was derived using the Stringway conversion chart as a basis. The data points from the Stringway conversion describe a relatively smooth curve so I felt it reasonable to assume the smooth nature of the curve would continue beyond the 13.0 KG/CM shown in the published conversion tabulation and graphic.

I have Yamaha Secret 04 and 06 racquets which have KG/CM stiffness ratings above the 13.0 KG/CM. I measured the Secret 04 at 17 KG/CM and the Secret 06 at 15.4 KG/CM. Others on the TW forum have stated the Secret 04 had an RA ~81 which was taken from an old review of the racquet and the Secret 06 had an RA of 78 (but the reference was even more ambiguous).

I took the conversion graphic provided by Stringway and extended the line further, doing my best to match the slope and curvature. After having done this in Photoshop I pulled the graphic into the Dagra graphic digitizer. This software allows for pulling data from graphs which can be put into spreadsheet applications like Excel.

After exporting the data produced by Dagra I imported it into Excel and (not surprisingly) the graphic produced was extremely similar to the Stringway conversion graphic and was very smooth. I was pleased that the 15.4 KG/CM was very close to the 78 RA provided by another source and the Secret 04 came to 80 RA which is very close to referenced RA noted above.

The utility of this data is perhaps dubious because of the lack of concrete references but it is perhaps better than the nothing I had to use for my racquets previously.

I have absolutely no idea as to whether this is of any use to anyone but myself, particularly since modern racquets having an RA over 70 are not in abundance. I believe information such as this should be shared instead of sitting on a hard drive. I know there is an equation for this data because the graphic is smooth but it is currently beyond my ability to tease out. I've read several times that the RA scale goes from 1 to 100 which is good information but it does not assist me in deducing an equation for this data. Unfortunately, producing the equation is not in my tool kit but perhaps there is a physicist or clever engineer who could perform the task with little strain just for the fun mental exercise.

The KG/CM data is reproducible by anyone having a Stringway Lab 2 and I admit knowing the RA does little (or nothing) for my game or equipment maintenance but I'm just a curious guy by nature.

KG/CM RA
4.5 => 21.6
5.0 => 29.6
5.5 => 35.9
6.0 => 41.4
6.5 => 45.9
7.0 => 49.7
7.5 => 52.9
8.0 => 55.9
8.5 => 58.6
9.0 => 60.8
9.5 => 62.9
10.0 => 64.7
10.5 => 66.4
11.0 => 67.9
11.5 => 69.3
12.0 => 70.6
12.5 => 71.8
13.0 => 73.2
13.5 => 74.4
14.0 => 75.3
14.5 => 76.1
15.0 => 77.0
15.5 => 77.8
16.0 => 78.6
16.5 => 79.3
17.0 => 80.0

 

[esgee48]

Dump the data into Excel. Then chart the data using col1 as X and col2 as Y. Use LINE type. Select option to display the formula used to fit the line as well as the R² which will indicate how well the formula fitted the data. I saw an R² of 0.993 which is basically right on.

 

[gkenney]

Dump the data into Excel. Then chart the data using col1 as X and col2 as Y. Use LINE type. Select option to display the formula used to fit the line as well as the R² which will indicate how well the formula fitted the data. I saw an R² of 0.993 which is basically right on.

Thanks very much!! I won't be doing anymore on this curiosity quest (actually I did more) but I've seen a number of times where people have asked for this translation/conversion equation and have been told it doesn't exist. Well, it still doesn't (actually) but this is the best approximation I could do. While Excel's trend line utility will display an equation I found it to be erratic (could very well be me) so I used the regression utility on http://www.xuru.org/rt/PR.asp#CopyPaste and increased the polynomial count to 8.

I'm very happy with the accuracy of the equation delivered but the accuracy of this equation and its utility is dependent the following: 1) the original accuracy of the conversion data from Stringway, 2) the assumption the data curve produced using the Stringway data continues smoothly past 13 kg\cm, and 3) my ability to accurately simulate the curvature of the graphed Stringway data past 13 kg\cm. Since the numbers are close to the Yamaha Secret 04 and 06 RA numbers I've seen from other sources I feel there is some hope of accuracy.

I used a 8th order polynomial and it’s within .1 RA for KG\CM values between 4.5 to 18. That is good enough for me but if someone wants it to be tighter they will need to increase the polynomial order until satisfied. Go outside the 4.5 to 18 range and the values are not reliable (producing ridiculous numbers). Inside that range the polynomial has a Coefficient of Determination: R2 = 9.999925589·10-1

The polynomial equation is: y = -2.493577256·10-7 x8 + 2.561143629·10-5 x7 - 1.144037698·10-3 x6 + 2.917184681·10-2 x5 - 4.678339064·10-1 x4 + 4.888608456 x3 - 33.22337151 x2 + 141.2515564 x - 239.9506264

Cut and paste the following Excel formula in cell B1 and put any KG\CM value between 4.5 to 18.0 in cell A1:

=-0.0000002493577256*(A1^8)+0.00002561143629*(A1^7)-0.001144037698*(A1^6)+0.02917184681*(A1^5)-0.4678339064*(A1^4)+4.888608456*(A1^3)-33.22337151*(A1^2)+141.2515564*A1-239.9506264

It will return a value within ~.1 RA of the values listed in the Stringway conversion chart.

 

[Martingale]

The following tabulation was derived using the Stringway conversion chart as a basis. The data points from the Stringway conversion describe a relatively smooth curve so I felt it reasonable to assume the smooth nature of the curve would continue beyond the 13.0 KG/CM shown in the published conversion tabulation and graphic.

I have Yamaha Secret 04 and 06 racquets which have KG/CM stiffness ratings above the 13.0 KG/CM. I measured the Secret 04 at 17 KG/CM and the Secret 06 at 15.4 KG/CM. Others on the TW forum have stated the Secret 04 had an RA ~81 which was taken from an old review of the racquet and the Secret 06 had an RA of 78 (but the reference was even more ambiguous).

I took the conversion graphic provided by Stringway and extended the line further, doing my best to match the slope and curvature. After having done this in Photoshop I pulled the graphic into the Dagra graphic digitizer. This software allows for pulling data from graphs which can be put into spreadsheet applications like Excel.

After exporting the data produced by Dagra I imported it into Excel and (not surprisingly) the graphic produced was extremely similar to the Stringway conversion graphic and was very smooth. I was pleased that the 15.4 KG/CM was very close to the 78 RA provided by another source and the Secret 04 came to 80 RA which is very close to referenced RA noted above.

The utility of this data is perhaps dubious because of the lack of concrete references but it is perhaps better than the nothing I had to use for my racquets previously.

I have absolutely no idea as to whether this is of any use to anyone but myself, particularly since modern racquets having an RA over 70 are not in abundance. I believe information such as this should be shared instead of sitting on a hard drive. I know there is an equation for this data because the graphic is smooth but it is currently beyond my ability to tease out. I've read several times that the RA scale goes from 1 to 100 which is good information but it does not assist me in deducing an equation for this data. Unfortunately, producing the equation is not in my tool kit but perhaps there is a physicist or clever engineer who could perform the task with little strain just for the fun mental exercise.

The KG/CM data is reproducible by anyone having a Stringway Lab 2 and I admit knowing the RA does little (or nothing) for my game or equipment maintenance but I'm just a curious guy by nature.

KG/CM RA
4.5 => 21.6
5.0 => 29.6
5.5 => 35.9
6.0 => 41.4
6.5 => 45.9
7.0 => 49.7
7.5 => 52.9
8.0 => 55.9
8.5 => 58.6
9.0 => 60.8
9.5 => 62.9
10.0 => 64.7
10.5 => 66.4
11.0 => 67.9
11.5 => 69.3
12.0 => 70.6
12.5 => 71.8
13.0 => 73.2
13.5 => 74.4
14.0 => 75.3
14.5 => 76.1
15.0 => 77.0
15.5 => 77.8
16.0 => 78.6
16.5 => 79.3
17.0 => 80.0

Thanks for the hard work!

 

[Sanglier]

That was a lot of work indeed! Personally, I didn't go that far. For my own spreadsheet, I was content to fit my equation to Stringway's conversion table as it is, without extensions, and found that a 5th order curve was more than adequate for the job. My curve begins to do funny things at the extreme ends (stiffer than the Wilson Profile, softer than the Lafourcade Aquillon), but we are guessing what the real curve should look like beyond those points, and no playable racquets live in those zones anyway, so I was not too concerned by that. In any case, flex measurements can vary much more than 0.1 RA even on the same racquet measured on different days, so anything that doesn't deviate noticeably from Stringway's table is definitely good enough for the sort of things we hobbyists want these values for.

This is my (somewhat inferior) equation, which I have used to collect data on over 800 racquets so far: RA = -159.7395 + 76.68511*X - 11.59075*X^2 + 0.9463168*X^3 - 0.03958306*X^4 + 0.0006626032*X^5 where X = Stringlab reading in kg/cm

 

[BorgCash]

The 04, 06 and 10. Same mold, but very different racquets, IMO. All are heavy, stiff frames, but the 04 is much more so than the other two.

IMO, the 04 is a one-of-a-kind powerhouse -- I've never swung another racquet quite like it for controllable power. The 06 and 10 are just average frames, at least that's what they seem to me.

I have 10 model and like it.

 

[Mig1NC]

I miss my Yamaha racquets. I don't remember selling them, I think they got lost when moved out of Florida. I think I had a crush on Sabatini, but didn't we all?

 

[Passingshot78]

Today i got my Secret04 and hit with it for couple minutes.

Extremely stiff frame especially when string with polly.
My only expiriance with Yamaha rackets is testing Secret ex almost 35 years ago as candidate for my regular frames but finally i end up with Head Elite pro widebodys. No regrets but kinda feel now that my choice (or rather my coach choice) was kinda conservative But maybe it looks like this from.time perspective now when we know that Yamaha was more modern racket even if Head was half/widebody But well in 1990 widebody looked like future right?

Even if my memory after 34 years might be not totally correct and EX is a different racket somehow the feel and sound is familiar for me
Very firm very heavy (366 Gramm string with tourna mega tac overgrip) and very stable frame Yet still kinda fast thru the air for its specs

 

[georgeyew]

Today i got my Secret04 and hit with it for couple minutes.

Extremely stiff frame especially when string with polly.
My only expiriance with Yamaha rackets is testing Secret ex almost 35 years ago as candidate for my regular frames but finally i end up with Head Elite pro widebodys. No regrets but kinda feel now that my choice (or rather my coach choice) was kinda conservative But maybe it looks like this from.time perspective now when we know that Yamaha was more modern racket even if Head was half/widebody But well in 1990 widebody looked like future right?

Even if my memory after 34 years might be not totally correct and EX is a different racket somehow the feel and sound is familiar for me
Very firm very heavy (366 Gramm string with tourna mega tac overgrip) and very stable frame Yet still kinda fast thru the air for its specs

Yours looks like a very clean frame with minimal defects. Take good care of it!

 

[Casey 1988]

Hi Ace,

I wish this help:

TENNIS RACQUET SPECIFICATION TABLE
Brand: Yamaha Secret-04 Racquet
Short Description: Players with big ground strokes will appreciate the frame’s solid and predictable performance. Yet it also delivers nice touch on volleys and a comfortable overall playability. Its design and construction make the racquet surprisingly quiet with little shock or vibration.
(1988 Tennis Magazine)
Head Size: 100 in2 / 645 cm2
Length: 27 in / 686 mm
Unstrung Weight: 12.3 oz / 350 g
Unstrung Balance: 6 pts HL / 315 mm
Composition: High Modulus Graphite / Hi-Resonant Frame Design
Beam Width: 25 mm Straight Beam
Power Level: Medium – High
Stiffness: 81 (Very Firm)
Swing Type: Moderate - Fast
Swing Weight: 327
String Pattern: 16 mains / 18 crosses
Grip Type: Yamaha synthetic grip
String Tension: 50 - 60 lbs / 22.7 – 27.2 kg recommended

I got one from my ex-boss (saying more than 10years ago) which he left behind for me. (At that time I knew nothing about tennis!)

This racket is really really stiff! I gave it a RDC check few months ago while having a new string job and still records 72! (Original is 81!!!) Very stable frame and must use some soft string on it. Anyway, the material which YAMAHA using is really amaze me. It absorb most of the shock from playing which this technology / material is using in 20 years ago!

Unluckily I found some cracks on it after the string job!

Anyway, while using this stick, I will found myself feel like using a shock-less and heavier version of Babolat PD.... (Roddick PD + Cortex? I can't tell)

Just my 2 cents.

This Raquet is as old as I am.

 

[Passingshot78]

Yours looks like a very clean frame with minimal defects. Take good care of it!

I will!

It looks like it wasnt played much

Ps: It says high modulus graphite but the look, weight and stifness tell me its rather concrete

 

[georgeyew]

I will!

It looks like it wasnt played much

Ps: It says high modulus graphite but the look, weight and stifness tell me its rather concrete

They are build like tanks. But because of the stiffness, it could be very brittle. I have heard of cases where the frame cracked from hitting the ground.

 

[michael valek]

Concrete is an accurate description. I love them. The yellow ex110 tour are also awesome. I just wish there was a racket which felt like the 04 but was 310/315g unstrung.

 

[kevin qmto]

That is indeed in fantastic shape. Much better than mine. Mine comes in at 368g strung, easily within the margin of scale or differences in grip weight/size, A+ quality control by Yamaha.

 

[Grafil Injection]

Mine is also 366g. I guess when you can make motorbike engines to 1/1000th inch accuracy, a racket is child's play.

 

[Passingshot78]

That is indeed in fantastic shape. Much better than mine. Mine comes in at 368g strung, easily within the margin of scale or differences in grip weight/size, A+ quality control by Yamaha.

I'm pretty sure that with new base grip minę would be around 368 Strung balance is 315 mm