ERT 300 Tennis Computer

MathieuR

Professional
I use the ERT 700 which I "enherited" when I bought lifestock and barrel from a retired stringer.
I also have the StringLab 2, which is more accurate, but more time-consuming. Measured values are in the same order of magnitude; SL2 always "ERT 700 + 1 " (kg/cm).

Edit: I think every stringer should use "some time" a DT- measuring device. It is the only way to have an accurate quality control on a string job. (apart from the feedback you get on playability)
 

shadow01

Semi-Pro
Are these things that much more precise than racquetune - and if they are - is the cost/benefit really worth it for any player let’s say UTR10 or below?
 

Erhard

Rookie
The ERT 300 results are rule-of-thumb estimate and not precice.
The Babolat RDC measuring results are accurate.
 

MathieuR

Professional
The Babolat RDC measuring results are accurate
Well, I wish that would be true. Thing is, you can only reproduce a consistent measurement from a Babolat RDC on another Babolat RDC.
What the conditions of the measurement are is a mystery.

I use a StringLab 2; gives consistent results. But uses its own set of conditions.
 

struggle

Legend
Are these things that much more precise than racquetune - and if they are - is the cost/benefit really worth it for any player let’s say UTR10 or below?
No comparison. No string factors to enter, no tapping with a spoon, etc.

I had one, sold it because i rarely used it. Sometimes I wish I still had it, but rarely. Hmmmm.
It really is a nice little unit if you're so inclined to use such.
 

shadow01

Semi-Pro
No comparison. No string factors to enter, no tapping with a spoon, etc.

I had one, sold it because i rarely used it. Sometimes I wish I still had it, but rarely. Hmmmm.
It really is a nice little unit if you're so inclined to use such.
Yep - I get that. Makes sense for professional stringers or stringers that are dealing with many different string types and different racquets that they want to track. Its market is definitely not for the hobby / friends & family stringer who has access to other tools that are still decent quality - just from a cost/benefit perspective imo. I do like that people are doing r&d into different technologies and innovating the sport!
 

Erhard

Rookie
Well, I wish that would be true. Thing is, you can only reproduce a consistent measurement from a Babolat RDC on another Babolat RDC.
What the conditions of the measurement are is a mystery.

The Babolat RDC DT mechanical measurement method is clearly defined:
A 40 mm disc pulls the string bed down by 10 mm in the middle. The required force is then displayed on a scale from 0 to 100. The measured value is independent of the tennis racket and the string material. For most players, the midpoint of 50 is a dynamic tension that plays very well.

This measuring method is the most reliable method for the stringer to check his work.
 

Erhard

Rookie
The Babolat RDC DT mechanical measurement method is clearly defined: A 40 mm disc pulls the string bed down by 10 mm in the middle.
The required force is then displayed on a scale from 0 to 100.
The measured value is independent of the tennis racket and the string material.
For most players, the midpoint of 50 is a dynamic tension that plays very well.

This measuring method is the most reliable method for the stringer to check his work.
 

MathieuR

Professional
This measuring method is the most reliable method for the stringer to check his work.
Bullocks!

A scale from 0 -100.....

What is the dimension of this unit? How is it calculated? Is the scale linear, exponential.....
 
Last edited:

Erhard

Rookie
Bullocks!

A scale from 0 -100.....

What is the dimension of this unit? How is it calculated? Is the scale linear, exponential.....
The dimension is actually irrelevant. Call it "Potatoes" ;)
0= no resistance (Hole). 100 = full resistance (Steel plate) .
After the measurement I know in which area my DT lies.
 
Last edited:

uk_skippy

Hall of Fame
IMHO, it makes senses only for a player who travels and has to use on-site stringers to have one.
As long as they know how to use it properly.
Onsite stringers should also have access to them as the number of times we get asked for this info; or to confirm we're hitting the numbers the player wants. They even ask to use 'our' ERT's; and I've had a major player keep hold of mine for 2 days!!
Different locations on the stringbed can give different results.
 

lidoazndiabloboi

Hall of Fame
As long as they know how to use it properly.
Onsite stringers should also have access to them as the number of times we get asked for this info; or to confirm we're hitting the numbers the player wants. They even ask to use 'our' ERT's; and I've had a major player keep hold of mine for 2 days!!
Different locations on the stringbed can give different results.
What is the proper location to measure? If a racket has 19 crosses, I would clip it on cross string 9 and 11, correct? What about a racket with 20 crosses?
 

Rabbit

G.O.A.T.
As long as they know how to use it properly.
Onsite stringers should also have access to them as the number of times we get asked for this info; or to confirm we're hitting the numbers the player wants. They even ask to use 'our' ERT's; and I've had a major player keep hold of mine for 2 days!!
Different locations on the stringbed can give different results.
yeah the instructions say to put it in the center and be consistent
 

uk_skippy

Hall of Fame
yeah the instructions say to put it in the center and be consistent
Definitely be consistent where you place it. We normally go for 9th cross down for the single leg on the ERT; doesnt matter what pattern the racquet is, with an exception of Wilson spin frames where we probably go for 8.

But even then, you need to place it in the exact same location
 

struggle

Legend
You can also compress the unit MORE or less to fit between different cross strings. (usually two options at best)

I've tried it both ways and it seems to remain consistent between the two, so that is good.

I found the unit to be very good/consistent and uses very sound technology. Very repeatable, etc.
 

Rabbit

G.O.A.T.
@struggle - agreed. The only real problem I had with mine was that you had to give it a few between measurements. Mine would crap out even with new batteries.

I think it's a fine unit and better than any phone app. However, all it did was get between my ears and dance. I sold it for what I paid for it and haven't missed it (until this thread ;) ).
 

struggle

Legend
Mine never never had a "crap out".

Similarly, don't miss it but wish i still had it....

When is Marietta gonna chime in?
 

Rabbit

G.O.A.T.
I'm still a relatively new stringer so maybe I'm wrong, but I just dont see any need for a device that measures DT.
If you were a touring professional forced to use a different stringer/machine at each stop, they are of use. You tell the stringer you want it strung at 58 pounds -- reference tension. The target for your dynamic tension is 52 pounds. So you tell the stringer 58 pounds and test the string bed when it comes back. If it's 54 pounds, then on your next restring you tell the stringer 56 pounds. Basically, the pro is trying to get a consistent feel from one stop to the next. Some pros really care about that, the majority I've strung for don't.

Please note these are only examples. no real data was used in the composition of the above statement.
 

struggle

Legend
I'm still a relatively new stringer so maybe I'm wrong, but I just dont see any need for a device that measures DT.
its the simplest, most straightforward way to “compare” and/or monitor tension trends (loss) over time. @Rabbits point above is spot on.

there are other ways, but they are not as repeatable or “accurate”. (Racquet tune, string meter etc…… in fact those are both pretty bad but better than nothing)
 

Pumpkin

Semi-Pro
If you were a touring professional forced to use a different stringer/machine at each stop, they are of use. You tell the stringer you want it strung at 58 pounds -- reference tension. The target for your dynamic tension is 52 pounds. So you tell the stringer 58 pounds and test the string bed when it comes back. If it's 54 pounds, then on your next restring you tell the stringer 56 pounds. Basically, the pro is trying to get a consistent feel from one stop to the next. Some pros really care about that, the majority I've strung for don't.

Please note these are only examples. no real data was used in the composition of the above statement.
Which professionals have you strung for?
 

Pumpkin

Semi-Pro
its the simplest, most straightforward way to “compare” and/or monitor tension trends (loss) over time. @Rabbits point above is spot on.

there are other ways, but they are not as repeatable or “accurate”. (Racquet tune, string meter etc…… in fact those are both pretty bad but better than nothing)
If I took a reading with the ERT300 three times a day, morning, noon and night after stringing a racquet, everyday for two weeks, would I get the same reading every time? This is without using the racquet.
 

MathieuR

Professional
If I took a reading with the ERT300 three times a day, morning, noon and night after stringing a racquet, everyday for two weeks, would I get the same reading every time? This is without using the racquet.
I think yes, if you pre-stretched the string (really pre-stretched, so ref.tension + 15-20kg).

In all other cases you will see a decline. Most of it first 24hrs. I think it will stabilize after 3 days.
(But if you would start playing, it will again have a decline. Most of it the first 2-3 hours)
The decline is very much string and gauge dependant.
 

Rabbit

G.O.A.T.
Which professionals have you strung for?
Pre-pandemic, we had a WTA ITF tournament here in town. The pros you may have heard of include:
Eugenie Bouchard (possibly - she played the tournament when I was stringing for it, nobody knew who she was then and I didn't write her down [dammit])
Johanna Konta
Jarmilla Wolfe
Laura Siegemund
Allie Kiick
Irini Falconi
 

struggle

Legend
Heck, I might buy it again. I rather enjoyed having it, just didn’t use it enough. For me it provided really solid data for personal use. Granted, I don’t really need that.
 

struggle

Legend
For example, my racquet freshly strung would DT at 40-41. Settled in at 37 or so for a prolonged period (NG mains, red Devil cross 60/56 reference)). Once at 34 DT it was noticeably done. Less control, I don’t break them often, but primarily because I don’t need to.
 

Pumpkin

Semi-Pro
Pre-pandemic, we had a WTA ITF tournament here in town. The pros you may have heard of include:
Eugenie Bouchard (possibly - she played the tournament when I was stringing for it, nobody knew who she was then and I didn't write her down [dammit])
Johanna Konta
Jarmilla Wolfe
Laura Siegemund
Allie Kiick
Irini Falconi
Oh cool. That's mad that you worked for them. Yeah, anyway, my last stringer put the DT on a sticker on my racquet. I never used it. For me, playing with the racquet tells me if I need an adjustment in tension. But pros are fussy. Sometimes they seem superstitious more than having true knowledge about equipment.
 

shug

Rookie
No need for it. Simply use the racquet to determine whether a tension adjustment is needed.
I will use it as a reference for my clients. It's not needed for me seeing's that I restring after every use, unless I'm exercising my serving muscles and don't expect my serves to drop.
 

Pumpkin

Semi-Pro
you’re all over the place. Never used one but then telling people there’s no need for one. I’d check out of this thread if I were you.

TIA
There's no need for threats. I asked you if the device would give the same reading if you took a reading 3 times per day for 14 days without using the racquet and you didn't answer? This makes me think it would give different readings.

If it says 50, then 48, 46, back to 48 is it really any use? Many a time I've taken a racquet out on court and felt the stringbed was too firm, but then after 20 minutes it settles in and feels good. This is in my opinion the best way to tell.

I'm just asking people to think twice before rushing out to spend their hard earned money on what appears to me to be an expensive little toy.
 

koolio

New User
I have one (borrowed from a friend) and have been using it to measure my stringing consistency since I just started stringing 2 months ago. It’s been very helpful to confirm my consistency.
Sometimes I use it to measure tension loss after playing xx hours
 
Top