BEERS ERT 3000 User manual
Microprozessor gesteuertes
Messgerät zur Bestimmung der
Besaitungs- und Spiel-
eigenschaften an jedem
Tennisracket. 1
Micro ordinateur destiné à
déterminer les caractéristiques du
cordage et du jeu pour chaque
raquette de tennis. 11
Uno strumento altamente
tecnologico per la misurazione
della caratteristica d'incordatura
delle racchette da tennis. 21
Micro computer for precise
determination of strings and
playing characteristics of any
Tennis Racquet. 31
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31
All string materials start loosing tension after the racquet is strung through repeated
impacts and through aging even if it has not been used
Restring the racquet when the DT-value has decreased
by 10% to maximum 20%
Never play tennis when the DT-value below 28 !
(Low ball control, risk of tennis elbow and back problems)
Technical data ERT 300 TENNISCOMPUTER
Field of application Tennis racquets
Dynamic system Electronic simulation of ball impact
Measuring of the resonance frequency Converting the string bed stiffness DT
DYNAMIC TENSION DT 20...65 DT (kp/cm; Newton/mm)
Accuracy +/- 1 kp/cm (+/- 1 digit)
Display Measurement 4...6 sec., Display 8 sec.
Dimensions 110 x 50 x 25 mm
Weight 50 g
Ambient temperature 5...45˚ Celsius / 40...115˚ Fahrenheit
Relative humidity 20%...80% (not waterproof)
Batteries 2 x CR 2032 coin type
Replace batteries when battery sign appears in display.
Caution: Do not loose the tiny screws.
Always use a proper desk top. plus pole up
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BEERS Technic GmbH
Professional Sports Equipment
CH-6330 Cham, Switzerland
www.beers-technic.ch
Know when to restring
2032
40
Product information - Manual - English
BEERS Technic GmbH, 6330 Cham, Switzerland
All rights reserved
DT range / Power of play
Lo DT 28...34 Defensive play
Mid DT 35...41 Dynamic, offensive play
Hi DT 42...46 Fast, aggressive play
Hi+ DT 47...54 Very fast, extremely
aggressive play
ERROR
No DT detection
Tension to low or incorrect handling
Place the device again
DYNAMIC TENSION DT (DT-value)
DT is the string bed stiffness
Higher DT for more control
Lower DT for more power (ball speed up)
Replace the batteries 2 x CR 2032 coin type
Restring the racquet at the latest
(Not recommended to play tennis when DT below 28)
kp, lbs.String tension kp, lbs.
To be read out at the DT system disc
DT is the string bed stiffness. The DT-value is the ball force in kilopond (kp) that is
needed to deflect the string bed 1 cm at the sweet spot (ball impact).
Internat. standard. units: kp/cm or Newton/mm.
DT determines the playing characteristics POWER and CONTROL.
What information gives the ERT 300
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33
LCD Display
Push button
Lever
Claws
Batteries 2 x CR 2032
ERT 300 Tenniscomputer
32
Product information - Manual - English
BEERS Technic GmbH, 6330 Cham, Switzerland
All rights reserved
1. Clip the ERT 300 in the center of the string bed
2. Push the button
3. After a few seconds read out the values determing the playing characteristics
How to measure the string bed stiffness
34
Hold the racquet at throat as shown
During the measurement hold the racquet steady, do
not touch or put down the racquet
Clip the ERT 300 in the center of the string
bed
The 3 claws hold the device parallel to the strings by
gentle spring tension (jump one cross string).
Push button to start the DT test
The ball impact is simulated electronically
(gentle vibrations).
The exact readings are displayed after 6...8 seconds.
(The device switches-off automatically)
DT-range / Power and aggressiveness of play
Example: Mid, dynamic and offensive play
DYNAMIC TENSION DT
Example: 38 DT
String tension kp, lbs.
To be read out at the DT-disc (page 38)
Important: The ERT 300 Tennis computer must be clipped at the center of the string
bed. If it is placed outside the center, e.g. towards the top or bottom, the measured
value will change. Normally in such a case the stringing appears to be tighter. This
corresponds to the reality. We however are interested in the impact zone. Variations
can also occur as a result of incorrect or defective stringing. For exact comparative
measurements (rechecks) the ERT 300 must always be applied to exactly the same
point, count or mark the strings.
Instructions
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2
1
3
Product information - Manual - English
BEERS Technic GmbH, 6330 Cham, Switzerland
All rights reserved
DYNAMIC TENSION DT
The DT-value is the stiffness of the string bed that
effects during the ball impact of any racquet.
DT determines the playing characteristics POWER
and CONTROL.
Higher DT provides more control
Lower DT provides more power (ball speed up)
DT is ball power in kilo pond (kp) required to depress the string bed 1 cm at the
sweet spot (ball impact).
Internat. standard units kp/cm or Newton/mm
The DT-value is measured with the ERT 300 Tennis computer by electronic simulation
of the ball impact (vibrations). All factors of influence such as racquet type, racquet
size, string pattern and string characteristics are automatically taken into account.
DT is the only realistic (since close to play) and precise value that can be measured
directly at the strung racquet.
What is the DT-value
36
The DT can be mainly determined by 4 ranges:
Lo, Mid, Hi, Hi+
(not to be mixed with the racquet size)
Each player determines his DT reference value respectively DT playing rang best
suited for his power level and style of play (overlapping possible). Optimum stringing
ensures play with maximum ball control and power reducing fatigue and the rebound
shock.
The string bed is the heart of the racquet. The proper combination of string and
Dynamic Tension DT suited for a specific style of play is necessary to obtain maximum
player performance.
How to find the optimum DT-value
DT 47 - 56DT 42 - 46DT 35 - 41DT 28 - 34
PLAYING Know your best DT
Defensive
from the
baseline
Dynamic
and offensive
Fast and
aggressive
Very fast and
extremely
aggressive
MORE CONTROL
MORE POWER
ENGLISH
37
Club / WTA Club / WTA / ATP ATP (mostly jused)Club Club / WTA Club / WTA / ATP ATP
HiMidLo Hi+
Product information - Manual - English
BEERS Technic GmbH, 6330 Cham, Switzerland
All rights reserved
Use the enclosed DT-disc for reading out the currant string tension kp (lbs.)
Example:
Racquet size MID+ (98 sq.in.)
string tension 25 kp (55 lbs.)
Measured DT-value
Set the measured DT-value 38 DT
Read out the average string tension 25 kp (55 lbs.)
After the stringing process, the tension of an individual string can no longer be measured
directly. The string bed stiffness DT is measured precisely by electronic simulation of the
ball impact. The corresponding string tension kp (lbs.) can be read at the DT-disc as an
average value.
25.0
55
TENNISCOMPUTER
DT is string bed stiffness
kp/cm, N/mm
(internat.standard.units)
DT determines the
mode of play.
kp/lbs. Average string tension. Deviations may occur depending
on string materials and stringing technic.
Restring the racket when DT tension loss 10% max. 20%.
All rights reserved
BEERS Technic GmbH
681 - 740 cm2
106 - 115 sq.in.
611 - 680 cm2
95 - 105 sq.in.
540 - 610 cm2
83 - 94 sq.in.
Racket SizeTension
kp
lbs.
kp
lbs.
kp
lbs.
OVER
MID +
MID
STRING
TENSION
kp
DYNAMIC
TENSION
DT is the only realistic and precise value
to be measured at the strung racket.
Defensive
from the
baseline
Dynamic
and offensive
Fast and
aggressive
Very fast and
extremely
aggressive
DT 47 - 56DT 42 - 46DT 35 - 41DT 28 - 34
PLAYING
Know your best DT
MORE CONTROL
MORE POWER
How to know the string tension kp (lbs.)
38
After determing of the suitable DT-value the corresponding machine pull tension set
in kp (kilopond) or lbs. (pounds) is to be read out at the DT-disc.
Example:
Racquet size MID+ (98 sq.in.)
pull tension 25/24 kp (55/53 lbs.)
Required string bed stiffness of
DT 38 which means dynamic
and offensive play
Set the required DT-value 38 DT
Read out the corresponding string tension 25 kp (55 lbs.)
String the racquet with 25/24 kp (55/53 lbs.)
The effective resulting DT-value may deviate slightly. This is not unusual and is
subject to string material, racquet design, string pattern and stringing technique etc.
The experienced stringer will adjust the tension on his stringing machine accordingly.
Check periodically the machine pull tension.
Do not forget: Within the first 2 to 4 hours after stringing, there is often a remarkable
tension loss of 2...4 DT, called the stabilization losses.
How to obtain the required DT-value
25.0
55
TENNISCOMPUTER
DT is string bedstiffness
kp/cm, N/mm
(internat.standard.units)
DT determines the
mode of play.
kp/lbs. Average string tension. Deviations may occure depending
on string materals and stringing technic.
Restring the racket when DT tension loss 10% max. 20%.
All rights reserved
BEERS Technic GmbH
681 - 740 cm2
106 - 115 sq.in.
611 - 680 cm2
95 - 105 sq.in.
540 - 610 cm2
83 - 94 sq.in.
Racket SizeTension
kp
lbs.
kp
lbs.
kp
lbs.
OVER
MID +
MID
STRING
TENSION
kp
DYNAMIC
TENSION
DT is the only realistic and precise value
to be measured at the strung racket.
Defensive
from the
baseline
Dynamic
and offensive
Fast and
aggressive
Very fast and
extremely
aggressive
DT 47 - 56DT 42 - 46DT 35 - 41DT 28 - 34
PLAYING
Know your best DT
MORE CONTROL
MORE POWER
ENGLISH
39
Product information - Manual - English
BEERS Technic GmbH, 6330 Cham, Switzerland
All rights reserved
