Stiffness Ratings

[StreetFighter]

All DA

Babolat AeroPro Drive GT 75
Babolat Aero Storm GT 75
Babolat Pure Storm GT 68
Babolat Pure Storm Tour GT 70
Babolat Pure Drive GT 75
Babolat Pure Drive Roddick GT 75

Dunlop Aerogel 4D 300 Tour 72
Dunlop Aerogel 4D 200 71

Head YouTek Prestige Pro 72
Head YouTek Radical Pro 72
Head YouTek Speed MP 71

Prince EXO3 Graphite 100 Mid+ 72
Prince EXO3 Rebel 95 72
Tecnifibre TFight 320 VO2 Max 75
Tecnifibre TFlash 315 SpeedFlex 78
Tecnifibre TFlash 315 VO2 Max 68

Volkl Power Bridge 10 Mid 71

Wilson BLX Six.One Tour 73
Wilson BLX Six.One 95 75

Yonex RDiS 100 Mid 73
Yonex RDiS 100 Midplus 72

 

[marsh]

Where did these come from? The 4d 200 is advertised at 62.

 

[StreetFighter]

Where did these come from? The 4d 200 is advertised at 62.

The advertised ratings are RA. I have listed DA ratings which are much more accurate.

 

[dekko1]

Prestige and Radical Pro at 72 and Yonex RDiS100 mid at 73?
I don't know but that does not sound right.

 

[StreetFighter]

Prestige and Radical Pro at 72 and Yonex RDiS100 mid at 73?
I don't know but that does not sound right.

Its not a typo. Radical Pro is listed as 58 RA (which is not stiff at all), but in playtests and DA ratings, it is more stiff. Same as the prestige.

 

[ChipNCharge]

What's the difference between RA and DA?

 

[El Diablo]

"Accurate" is meaningless unless you indicate what the measurements are standardized against and why the standard should be accepted is valid. The data here is otherwise of no value.

 

[bsandy]

Is RA standard against something or just relative to itself?

Trying to do some research on DA and cannot find anything.

and . . .

To say the YouTEK Radical Pro and the YouTEK Prestige Pro have the same stiffness is not believable to me.

. . . Bud

 

[AceInYourFace]

DA= dumbass ...dunno?

 

[rich s]

All DA

Babolat AeroPro Drive GT 75
Babolat Aero Storm GT 75
Babolat Pure Storm GT 68
Babolat Pure Storm Tour GT 70
Babolat Pure Drive GT 75
Babolat Pure Drive Roddick GT 75

Dunlop Aerogel 4D 300 Tour 72
Dunlop Aerogel 4D 200 71

Head YouTek Prestige Pro 72
Head YouTek Radical Pro 72
Head YouTek Speed MP 71

Prince EXO3 Graphite 100 Mid+ 72
Prince EXO3 Rebel 95 72
Tecnifibre TFight 320 VO2 Max 75
Tecnifibre TFlash 315 SpeedFlex 78
Tecnifibre TFlash 315 VO2 Max 68

Volkl Power Bridge 10 Mid 71

Wilson BLX Six.One Tour 73
Wilson BLX Six.One 95 75

Yonex RDiS 100 Mid 73
Yonex RDiS 100 Midplus 72

How is DA measured?

We know how the Babolat RDC measures RA.... show us or explain how DA stiffness is measured!

thanks

 

[flashfire276]

I don't know man. Those ratings sound a bit too crazy.

 

[Hidious]

Here are my measurements in PA ratings.

Babolat AeroPro Drive GT 55
Babolat Pure Drive GT 55
Babolat Pure Drive Roddick GT 55
Dunlop Aerogel 4D 300 Tour 52
Head YouTek Prestige Pro 52
Prince EXO3 Rebel 95 52
Tecnifibre TFight 320 VO2 Max 55
Volkl Power Bridge 10 Mid 51
Wilson BLX Six.One Tour 53
Wilson BLX Six.One 95 55
Yonex RDiS 100 Mid 53
Yonex RDiS 100 Midplus 52

 

[bsandy]

Here are that BUD ratings:

YT Radical Pro - MMM
YT Prestige Pro - OOH
Babolat Pure Drive Roddick GT - MF That Hurts

 

[tennis005]

^^^ Best rating system ever!

 

[StreetFighter]

It originated from the old "RA Machine" which was a mechanical machine made by Babolat back in the late 70s and early 80s. Pacific, the German company who were leaders in stringing machine technology with the first computerised electronic stringing machine in the early 80s, came out with an electronic version of Babolat's RA machine called the "Multi-Test-Computer", an all in one racquet diagnostic machine.

Babolat named their stiffness rating "RA points" so Pacific named theirs "DA points" to differentiate between mechanical (reading from a simple dial) and electronic (digital) readings.

Neither scale is in any standard units of measurement, i.e. they are both independant scales ranging from 0-100 with 100 meaning no deflection.
Please note, there is no correlation between the two scales, i.e. it is not possible to convert from RA to DA or vice versa - like I said they are totally independant scales.

As for how are they measured? ... they are both a measure of the deflection at the tip of the head of the frame when a force is applied at that point and the frame is supported in two locations, at the shaft and at the handle.

Please note that this does by no means give an accurate indication of what is going on in various locations along the beam in regards to vibration frequencies - e.g. you could have two different racquets with the same stiffness rating and yet they could feel totally different to hit with because what you feel is actually the vibration frequencies along the frame.

 

[cellofaan]

Neither scale is in any standard units of measurement, i.e. they are both independant scales ranging from 0-100 with 100 meaning no deflection.
Please note, there is no correlation between the two scales, i.e. it is not possible to convert from RA to DA or vice versa - like I said they are totally independant scales.

As for how are they measured? ... they are both a measure of the deflection at the tip of the head of the frame when a force is applied at that point and the frame is supported in two locations, at the shaft and at the handle.

Could you elaborate on this a bit further?
You say they measure basically the same thing, deflection at the tip. Is the frame supported at the exact same places as on a babolat rdc machine? In that case I would expect there is some way to convert them, like Celsius to Fahrenheit.
But as it is not convertable, something would be (even slightly) different, like the support points.
Am Icorrect, and if so, what is the difference?

 

[origmarm]

I've always struggled with the difference also. It seems to me from what I remember that they essentially measure the same thing, just the DA scale was 'tighter' i.e. 0 was different if that makes sense. Is this correct?

Your measurements or from another source? Re the numbers some of them do seem to correlate to what I've felt playtesting. I've always felt the new 6.1s were right up there with the PDRs in terms of stiffness.

Some of the comments in this thread are distinctly unhelpful to someone trying to share information with the board. Just because you don't understand it does not make it redundant information. Thanks Streetfighter for the post.

 

[rromeo]

I am also very interested in how to get more info on the DA ratings of various racquets. Currently experimenting w/various racquets and customizations to find the combo that "feels" best. Also what do the acronyms RA and DA stand for? Thanks for the info.

 

[Hidious]

I do have to apologize to StreetFighter for my childish post. I had never heard of DA ratings and couldn't find any info on the net so i assumed it was a hoax.

Sorry and thanks for posting!

 

[ollinger]

We've still not been told why we should consider DA data "much more accurate." Because it is electric and the other is mechanical?? I don't think so. Mechanical (mercury tower) blood pressure machines are universally regarded as more accurate than the electric machines, for example.

 

[flashfire276]

We've still not been told why we should consider DA data "much more accurate." Because it is electric and the other is mechanical?? I don't think so. Mechanical (mercury tower) blood pressure machines are universally regarded as more accurate than the electric machines, for example.

Agreed. How can we trust his findings that its so much more accurate than from the information what we already know? So if an arm friendly racquet (Pure Storm) is rated to be 68, then do we have to redo our whole opinion on what rating is way past our limit (for example: anything 67 and higher is stiff for me)?

 

[corbind]

Why did this thread die? Someone must know more about RA and DA and be able to contribute...

 

[li0scc0]

Agreed. How can we trust his findings that its so much more accurate than from the information what we already know? So if an arm friendly racquet (Pure Storm) is rated to be 68, then do we have to redo our whole opinion on what rating is way past our limit (for example: anything 67 and higher is stiff for me)?

Yet I know quite a few people who say the Pure Storm GT is horribly stiff and painful. For many of us it has all the negatives of 'stiffness' (vibration, stiff feel) without the positives (Gamma T-5 or Babolat Pure Drive power).
Also, for me, the 6.1 is the most stiff and powerful racquet I have used.