Blade charactersistics: TBS

Every blade has its own characteristics, and I think that the characteristics of the TBS are very special, far from being neutral (in the following I will assume a neutral value of 100, values above 120 and below 80 are extreme values).


-Weight: In average a TBS is about 91 gr. Value: 112

-Thickness: 5.8 mm. Value: 97

-Balance: Slightly head heavy, but not excessively head heavy. Value: 103

-Speed (restitution): The TBS is a very fast blade. It is on the border between Off and Off+. Value: 112

-Stiffness: The TBS is a very stiff (stable) blade. Value: 113

-Vibration: I see that vibration is often linked to hardness and consequently a blade with sharp feeling (little vibration) is often considered as a hard blade. This one-to-one interlinking is wrong in general. The TBS has little vibration. High values mean little vibration. Value: 113

-Repulsion: Repulsion represents the feeling of catching the ball. It is equivalent to dwell. Few players can differentiate between vibration and repulsion (usually vibration is the dominant feeling). High values mean high repulsion, i.e. weak catching. The TBS catches the ball deeply. Value: 92

-Overall hardness: This is a combination of stiffness, vibration and repulsion. Many players can not catch the different feelings associated to hardness but just this overall feel. Value: 104


What makes the TBS so special is that it shows high speed, high stiffness, little vibration but nevertheless almost a neutral overall feel and a low repulsion level. The combination of high speed and low repulsion level is what makes it such a great blade for skilled topspin attackers.



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Measurement procedure:

-Speed: A ball of certain speed is shot at the racket and the rebound speed is measured. This is done for three different impact speeds (approx. 5, 25 and 50 miles/hour). For each impact speed, the rebound speed is averaged over 10 shots. The blade is fixed 2 and 8 cm below the handle. The final value is an average over the three impact speed. Reference (100) is Rosewood V.

-Bending stiffness: Measured amount of bending (in mm) vs applied force. The blade is fixed 2 and 8 cm below the handle. Reference (100) is Rosewood V.

-Vibration: This is essentially dampening. The exponential decrease of the vibration amplitude is measured. The blade is fixed 2 and 8 cm below the handle. Reference (100) is Rosewood V.

-Repulsion: The time of the ball on the blade is measured. The blade is fixed 2 and 8 cm below the handle. Reference (100) is Rosewood V.







Edited by High_Arc - 12/16/2011 at 1:49pm

A Touch wrote: High Arc, may you reply or PM  me characteristics of ZJK blade and differences to TBS? Thanks, very much appreciated.

There is some ongoing discussion about the characteristics of the ZJK ALC. First some facts: It is very similar to the Viscaria. The shape of the head is different (both the head and the wings near the handle are less broad as compared to the Viscaria).

TBS
-------------
Weight: 112
Thickness: 97
Balance: 103
Speed (restitution): 112
Stiffness: 113
Vibration: 113
Repulsion: 92
Overall: 104


ZJK ALC
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Weight: 108
Thickness: 97
Balance: 100
Speed (restitution): 113
Stiffness: 113
Vibration: 110
Repulsion: 89
Overall: 100


Overall the ZJK ALC is very similar to the TBS, but it gives more feedback (more vibration, i.e. lower value), it is softer and has a higher dwell (lower repulsion).

It should be noticed that
-weight
-balance
-speed
-stiffness
-vibration
-repulsion
are measured values. The neutral value of 100 (zero point) is set more or less arbitrarily.

-Speed and repulsion were measured with a high speed camera (not state-of-the-art, but very good). The values are averaged over three impact speed. The blade is fixed at the handle and for speed the rebound height is measured (for higher speed the time for a certain distance). For repulsion, the time of the ball on the blade is measured. The blade is fixed at two positions: 2 cm and 8 cm below the top of the handle.

-For stiffness the bending vs the applied force is measured. Blade mounting is like above.

-Vibration is measured as the average exponential decrease in the vibration amplitude.

-Overall feel is my personal impression and therefore purely subjective.

-The standard deviation for two identical measurements (including remounting the blade) is smaller than 1 point (except for vibration, where the standard deviation is 3 points).

-Measurements were done at the ETH.



Edited by High_Arc - 12/16/2011 at 2:02pm

A Touch wrote: Thank you very much.Could tell me which has higher throw? Which has a more comfortable handle and what rubbers would suit it?

ZJK ALC has a higher throw if you have T05 on top (my personal impression). I think that both handles are comfortable, but that's very personal. The FL handle of the ZJK ALC is much broader than the one of the TBS.



Edited by High_Arc - 12/16/2011 at 7:16am

does your measurements get affected by blade weight? In general what would happen to the values if you get a lighter blade of the same model?

Well, if you have larger hands, ZJK has a better FL handle. Right? Because TBS FL is just way too small for me. Isn't too personal ;)

do you have the values for Ebenholz VII? Would appreciate if you could post that as well. I have an opportunity to get a very light one - under 85g.

ejmaster wrote: the data provided by high_arc are very interesting and imo confirm my feeling about the zjk blade.   Being the tbs (particullarly the last series) quite stiff the zjk is same stiffness but even with more speed and less vibration so it brings a more rigid and overall harder feeling.   but the worst part about the zjk has to do with less vibration and repulsion (the later maybe due to a somewhat softer touch) which brings imo a less lively blade.   less lively blade and with reduced feeling margin.   vibration brings feeling though also brings some disturbing. when drilling with the zjk the feeling is good at first because there is less disturbing feeling. however afterwards you miss that loss of feeling. worse control and less touch margin.   about the handle, the one i got fl handle was same thickness and width than my fl tbs. but i also read from people that one can get different thickness and width zjk handles. there is a deviation.

I should have stressed out a bit more that the way I write the values higher values for Vibration actually mean less vibration. This is confusing but I wanted to be consisting in the sense that loosely speaking faster=harder=less vibration=less dwell (which is of course not always true).

Most values have physical units, but for simplification I chose an arbitrary scale (where only relative changes are truly correct). E.g. stiffness is measured as dx/dF, where x is the amount of bending (in mm) and F is the applied force; Speed is measured as the ratio of incoming ball speed and outgoing ball speed (as determined via time to travel a certain distance), repulsion is measured as the time the ball stay on the blade etc.

You will see that the Viscaria shows more vibration (i.e. has a smaller value) than the ZJK ALC.




Edited by High_Arc - 12/16/2011 at 11:48am

High_Arc wrote: ejmaster wrote: the data provided by high_arc are very interesting and imo confirm my feeling about the zjk blade.   Being the tbs (particullarly the last series) quite stiff the zjk is same stiffness but even with more speed and less vibration so it brings a more rigid and overall harder feeling.   but the worst part about the zjk has to do with less vibration and repulsion (the later maybe due to a somewhat softer touch) which brings imo a less lively blade.   less lively blade and with reduced feeling margin.   vibration brings feeling though also brings some disturbing. when drilling with the zjk the feeling is good at first because there is less disturbing feeling. however afterwards you miss that loss of feeling. worse control and less touch margin.   about the handle, the one i got fl handle was same thickness and width than my fl tbs. but i also read from people that one can get different thickness and width zjk handles. there is a deviation.   I should have stressed out a bit more that the way I write the values higher values for Vibration actually mean less vibration. This is confusing but I wanted to be consisting in the sense that loosely speaking faster=harder=less vibration=less dwell (which is of course not always true). Most values have physical units, but for simplification I chose an arbitrary scale (where only relative changes are truly correct). E.g. stiffness is measured as dx/dF, where x is the amount of bending (in mm) and F is the applied force; Speed is measured as the ratio of incoming ball speed and outgoing ball speed (as determined via heights), repulsion is measured as the time the ball stay on the blade etc. You will see that the Viscaria shows more vibration (i.e. has a smaller value) than the ZJK ALC.

Edited by ejmaster - 12/16/2011 at 1:27pm

thanks for that info. That is indeed surprising that ratios for speed are independent of impact.

stigatt wrote: thanks for that info. That is indeed surprising that ratios for speed are independent of impact.

Just looked up some values. for the offensive classic the rebound speed gets comparably smaller for higher impact speed. if you artificially set the ratio of the rebound speed for offensive classic and TBS = 1 for 5 miles/hour, this ratio is about 0.8 for high impact speed. But the Offensice Classic is the only true exception.

well i had not read your last post.

Edited by ejmaster - 12/16/2011 at 12:54pm

ejmaster wrote: in anycase high_arc it is a nice work what you did. this data is good to work with it.   thank you.

Thanks. I tried to do something objective rather than subjective. I know that there is room left for improvement of the procedure, let's see whether I'll find time or not (it took me and a friend almost two days to do these tests).

I am interested to see the results, too.  

High_Arc, it is interesting you have similar values to IGGSTERN's site at least for the TBS which I checked. If you have similar results for different blades like OC and Rosewood, then we might extrapolate that their results for blades you did not test would have been the same if you tested them also. 

edit: I mean the values are not exactly the same, but the relative assessments are the same. For example, TBS is fast and stiff (not too fast & not too stiff) but low repulsion.

Edited by stigatt - 12/16/2011 at 1:57pm

Thank you for details, High_Arc. I'm especially interested, if you estimated absolute values of the repulsion time. If you did, what are they in average?
Sorry for many questions, but I have another one to ask )) Do you have an idea, what properties of blades define dwell time at low and high speed impacts? I mean, does stiffness of the blade and hardness of the outer ply contribute equally, irrespective of impact speed? E.g., both Viscaria and YE have comparable soft feel and supposedly comparable DT. Nevertheless, spinning ball over the table is much easier with YE.