Difference between stiffness amd hardness

Hurricane_boss · Nov 11, 2017

Hi all, I am still kind of new to TT blades and can someone please tell me the difference between stiffness and hardness of a blade? For example a hurricane 301 blade has a very low stiffness but a medium hardness?! I want to have hard rubber on a soft blade but does this mean I need a soft AND flexible blade? Help plz

langel · Nov 11, 2017

Stiffness corespondes to the blade flexyness, hardness - to the feel of the outer ply.

Astorix · Nov 11, 2017

langel said:
Stiffness corespondes to the blade flexyness, hardness - to the feel of the outer ply.

good explanation! just wanna ad that the lower stiffness correlates with longer dwell time what makes it easier to impart spin

Hurricane_boss · Nov 11, 2017

wait so aside from the fact that carbon outer plies have a larger sweetspot are there any other differences? Im not really a begginner in table tennis but I just dont know that much about equipment. Thx

Baal · Nov 11, 2017

Hard blades vibrate quite a bit at quite high frequencies when the ball strikes. Soft blades don't. Flexy blades vibrate a lot at low frequencies and stiff blades don't. Blades vibrate at more than one frequency at the same time. (Same reason a guitar and violin sound different even when they play the same note). So soft blades can still be stiff (Butterfly Iolite is a classic example). Some composite materials like arylate have a particular property of absorbing high frequency vibration (and this becomes more noticeable if the arylate is closer to the surface) but in a thin large blade head arylate will still allow flex.

It amounts to the same thing Iangel wrote but this way ofbthinking about it explains why the hard outer ply feels the way it does. The figh frequency vibrations will propagate more through the outer ply I suspect.

langel · Nov 11, 2017

If you build a dynamic graph of stiffness and/or hardness change of a blades with different composition, as a function of speed/angle/hit strenght/vector, you may find a lot of differences.
But besides that stiffness and hardness are just what they are - basic characteristics of a blade.

langel · Nov 11, 2017

Baal said:
Hard blades vibrate quite a bit at quite high frequencies when the ball strikes. Soft blades don't. Flexy blades vibrate a lot at low frequencies and stiff blades don't. Blades vibrate at more than one frequency at the same time. (Same reason a guitar and violin sound different even when they play the same note). So soft blades can still be stiff (Butterfly Iolite is a classic example). Some composite materials like arylate have a particular property of absorbing high frequency vibration (and this becomes more noticeable if the arylate is closer to the surface) but in a thin large blade head arylate will still allow flex.

It amounts to the same thing Iangel wrote but this way ofbthinking about it explains why the hard outer ply feels the way it does. The figh frequency vibrations will propagate more through the outer ply I suspect.

Yes, that's right.
Would like to add that composite blades sometimes react not exactly the way we would expect just looking on the ply composition, especially if we look at them more deeper as I wrote above.
Some brands /like Xiom/ give very good information about blades behaviour depending on basic factors and its always good to consider such info, as just a single value can be a good starting point of consideration, but is not very appropriate in depth.

Hurricane_boss · Nov 11, 2017

I am planning to get a DHS 301 blade for christmas and on TTDB it is apparently the most flexy blade you can buy?! (0.9 stiffness but 4.8 hardness) Is this true? Because I'm planning on putting another hard chinese rubber for forehand and I don't wanna get ripped off XD.

And by the way, from some other articles I read, isn't carbon supposed to be really hard and stiff? So why is this blade still flexy? Thanks

Astorix · Nov 11, 2017

Hurricane_boss said:
I am planning to get a DHS 301 blade for christmas and on TTDB it is apparently the most flexy blade you can buy?! (0.9 stiffness but 4.8 hardness) Is this true? Because I'm planning on putting another hard chinese rubber for forehand and I don't wanna get ripped off XD.

And by the way, from some other articles I read, isn't carbon supposed to be really hard and stiff? So why is this blade still flexy? Thanks

i wouldn`t take those ratings as 100% accurate, these are user made and more or less subjective perception.
just take them for comparison.
when the carbon layer is placed near the core like at the h301 and not directly under the outer ply like most it tends to be more flexible i would say.
i think you can`t do anything wrong with the h301. DHS blades tend to go really well with their rubbers and it is definitely great value for the money.
i play the DHS Fang Bo Carbon as substitute, the two blades differ only in the outer ply and i am very satisfied with it.
im sure you will like the h301 as well.

Hurricane_boss · Nov 11, 2017

WAIT WHAT?!?! The Fang Bo Carbon is 5.0 STIFFNESS?!?! So does that mean the 301 is similar to that too?!?! PLZ HELP

Hurricane_boss · Nov 11, 2017

Okay.... So someone just posted a review of this blade 33 minutes ago... and the guy rated stiffness 5.0?! And the other guy rated it 3.0 and how is the stiffness 1.4?!?! Shouldn't it be 4.0?! OMG Im freaking out

Astorix · Nov 11, 2017

these ratings aren`t accurate. do not take them as the holy crail.

Baal · Nov 11, 2017

Sadly the only way to know is to try yourself.

langel · Nov 11, 2017

You must have in mind that there is no an absolute measuring scale for these characteristics.
The producers gradings are just indicative and the users personal ratings are comparitive, depending on their individual experiance with other setups.
In order to find the appropriate answer you have to do a critical reading upon users information, considering many factors as players style, distance, rubbers used, and reference setups they use to compare with.
When you analyse this info you can compare the results with your feelings about what you have in your hands and estimate what you may have if change something in the system.
Don't think about carbon, limba, koto, tensor, etc. as a single material. In a bat they work as a system and the best system for you is the system you feel the best synergy with. Sometimes it takes a while to find it, but don't give up.

Hurricane_boss · Nov 12, 2017

hey man, thanks for all that! but can you please furthur explain what these different plys do?! Also, what would suggest for me? I want a as flexy blade as possible.,Thanks

PiZa · Nov 12, 2017

Here you have very good explanation of various plies specification.
http://stervinou.net/ttbdb/lexik.php

Also if you want very flex blade you need rather thin one and not stiff.

Difference between stiffness amd hardness

Member

Well-Known Member

Member

Member

Well-Known Member

Well-Known Member

Well-Known Member

Member

Member

Member

Member

Member

Well-Known Member

Well-Known Member

Member

Member

Similar threads