Racquet Mod Formulas: Matching Specs

[Duzza]

Originally Posted by andrew_b

OK, help please? First, though, thanks for taking the time to provide this to the community! You've obviously put a bitof work into it, and you're not afraid to admit parts have discrepancies and to work to address them.

So, I played with it with my racket settings and a setup I'd like to try out:

weight: 340.48g
Balance: 32
Swingweight: 335

Final weight: 352.48
Final balance: 32
Final swingweight: 365
weight mass 1: 7
weight mass 2: 5

The above give me locations of (roughly) 14 and 57, which is OK.

I, too, get a pretty big difference in swingweight when I plug the starting values, weights, and locations into Steve's spreadsheet. It ends up saying the swingweight is 346.

Sorry I can't post the images like someone else did, don't know how to do that. Any idea why the swingweights are so different, or which one is closer?

Thanks,
Andrew

Andrew, if the 2 spreadsheets don't agree then it's impossible I've found. If you try to get too big a swingweight it may not work and Steves spread is pretty accurate(to about 0.03 off) so 2 things you can do: Lower the desired swingweight unfortunately, or mess around with the mass in location 1(the one in white) until both spreadsheets agree

[Duzza]

Wow that http://specgeek.50megs.com/LeadTapeO...ionApplet.html is quite confusing, the results field is too small!

[stules]

Hi
I have taken a few of the formulas that have been on various threads lately,
and combined them into a more more useable format.
Thanks to all that contributed. Instructions are included particularly Travlerjm, Amone, and TonyB. Should be self explanetory.
I hope this helps............
download it here
http://www.badongo.com/file/1604939
You have to go to the bottom of the page, and read the instruction.

I figure you have Excell on your pc.

open the spreadsheet.

There is no need to copy the formula. Across the bottom of the page are 'tabs. I have inserted about 10 popular racquets there, with the specs off TW. click on the tab, and mod away to your hearts content.

When you wish to use a new racquet,
'right click' on any tab at the bottom of the page,
click 'copy sheet'
tick the sheet you wish to copy
'ok'
'right click' on the new tab and rename to the desired name.

The blue fields need to be filled out, ie if your racqet length is 69.5cm, you need to insert that number in the blue square.

Fill out the blue 'weight added' squares with grams of lead at a distance from the butt (both figures can be varied) but leave the space blank or with a '0' in it if you don't place lead there. Negative numbers work as well, eg if you trim down the grommets, weigh them before and after, and place the difference as a minus figure at the average distance from the butt where you trimmed.

TW's figures are close, but they are averages of that racquet, and not for your specific one. ie if you have a 4 5/8 grip it may be heavier, and slightly more head light. With this in mind I weigh the actual racquet I am modding, measure its actual balance point (with overgrip and dampener on) and check the SW using the pendulum method (as per the bottom of the spreadsheet) and then insert these figures into the start of the spreadsheet instead of TW's. Either way is reasonably close.

Please follow these instructions, and hopefully it will be reasonably self explanatory. If you have any difficulties, please say so, as you won't be the only one. I have tried to label everything on the spreadsheet to make it useable without complicated instructions.

PS, I don't think there are any mistakes, but caveat emptor...
Regards Stuart

[Duzza]

Hey stules nice work, what is the quality index? Also i didnt like the way it rounds up on grams added and fyi a standard racquet is actually 68.58 cm and why would you remove the grip and not add a new one on? And why does, with the balance if you have 12.5 inch balance equal 8.5 points? If its a standard 27 inch racquet surely the balance is (13.5-12.5)*8? Also this one also involves trial and error unlike Amones. Maybe if you asked him if you could include his work in yours? What i mean is with Amones you can choose the desired swingweight, balance and then mix around with the 1st location of weight until you find places that work.
eg.

[stules]

Hi Duzza
Hope you find it useful.
what is the quality index?
http://www.racquetresearch.com/complete_idiot.htm

Also i didnt like the way it rounds up on grams added and fyi a standard racquet is actually 68.58 cm
Actually not... I measure the racauet and use the actual length in cm's and mms.

why would you remove the grip and not add a new one on?
Two reason, to remove abut 13gm from the total weight, and hence give me more room to customise before coming up against my total weight barrier.ie, if the total weight is 343gm and my target total is 346, I can only add 3 gram to the racquet, not much of an adjustment. If I remove the grip, I now get about 16 gram to add anywhere to achieve my atarget weight. Second reason is that I like the feel of the 'sharper edges of the handle with just an overgrip only. It feels to me easier to change grip positons. Personal preference. I buy a 4 5/8, then take off the grip, add an overgrip and have a 4 1/2 handle.

And why does, with the balance if you have 12.5 inch balance equal 8.5 points? If its a standard 27 inch racquet surely the balance is (13.5-12.5)*8?
Easy answer, just adjust the Racquet lenght field to 69cm , if it is a 27" racquet. THat example is 68.58cm ie not 27". hence the discrepancy

Also this one also involves trial and error unlike Amones. Maybe if you asked him if you could include his work in yours? What i mean is with Amones you can choose the desired swingweight, balance and then mix around with the 1st location of weight until you find places that work.
I find trial and error not too hard. I know how much weight I have to play with ie 330 starting weight, aiming for 346, I know I have to add 16 gm.
Preference is at least 6gm at 3/9 for stabilty, then I play with thel last 10 to get the total swingweight and balance, which is the juggle. Try it, not too time consuming.
Regards Stuart

[Amone]

Well, after more consideration, I noticed what caused the problems, and why there were problems:

Having a low resultant-SW caused it to just plain overshoot the numbers, for whatever reason. The Balance and Weight results, however, were approximately perfect.

The cause of this was my original equation: The part of the formula I used for weight placement was horrendously over-simplified, and I'm working now on a new one, using a more proper balance marker.

A new sheet should be out within a matter of hours.

EDIT: No, not tonight. I will spend some time on it tomorrow in my blow-off classes for the day.

[Duzza]

Originally Posted by stules

Hi Duzza
Hope you find it useful.
what is the quality index?
http://www.racquetresearch.com/complete_idiot.htm


Actually not... I measure the racauet and use the actual length in cm's and mms.


Two reason, to remove abut 13gm from the total weight, and hence give me more room to customise before coming up against my total weight barrier.ie, if the total weight is 343gm and my target total is 346, I can only add 3 gram to the racquet, not much of an adjustment. If I remove the grip, I now getabout 16 gram to add anywhere to achieve my atarget weight. Second reason is that I like the feel of the 'sharper edges of the handle with just an overgrip only. It feels to me easier to change grip positons. Personal preference. I buy a 4 5/8, then take off the grip, add an overgrip and have a 4 1/2 handle.

Fair enough, I just thought it would be a waste of time filling in the numbers of removing a grip and then putting it back on, with an overgrip only of course it makes sense.

And why does, with the balance if you have 12.5 inch balance equal 8.5 points? If its a standard 27 inch racquet surely the balance is (13.5-12.5)*8?
Easy answer, just adjust the Racquet lenght field to 69cm , if it is a 27" racquet. THat example is 68.58cm ie not 27". hence the discrepancy


What i mean is with Amones you can choose the desired swingweight, balance and then mix around with the 1st location of weight until you find places that work.
I find trial and error not too hard. I know how much weight I have to play with ie 330 starting weight, aiming for 346, I know I have to add 16 gm.
Preference is at least 6gm at 3/9 for stabilty, then I play with thel last 10 to get the total swingweight and balance, which is the juggle. Try it, not too time consuming.
Regards Stuart

Thanks for replying

Originally Posted by stules

Actually not... I measure the racauet and use the actual length in cm's and mms.

Two reason, to remove abut 13gm from the total weight, and hence give me more room to customise before coming up against my total weight barrier.ie, if the total weight is 343gm and my target total is 346, I can only add 3 gram to the racquet, not much of an adjustment. If I remove the grip, I now get about 16 gram to add anywhere to achieve my atarget weight. Second reason is that I like the feel of the 'sharper edges of the handle with just an overgrip only. It feels to me easier to change grip positons. Personal preference. I buy a 4 5/8, then take off the grip, add an overgrip and have a 4 1/2 handle.

Fair enough, I just thought it would be a waste of time filling in the numbers of removing a grip and then putting it back on, with an overgrip only of course it makes sense.

Originally Posted by stules

And why does, with the balance if you have 12.5 inch balance equal 8.5 points? If its a standard 27 inch racquet surely the balance is (13.5-12.5)*8?
Easy answer, just adjust the Racquet lenght field to 69cm , if it is a 27" racquet. THat example is 68.58cm ie not 27". hence the discrepancy

But adjusting the CM length does nothing different because you're equation for calculating the points involved inches, ie. 27*2.54
EDIT: Hmm I'm a little confused by my own work now, don't worry about it. ALSO: Where do you get the (/0.3) from? Like your equation is Half the length minus the balance point from the buttcap divided by 0.3. I'm sorry but I'm not familiar with why the 0.3 is there. Something to do with the Inch/CM conversion?

[stules]

0.3 is 3mm ie 1/8" ie 1 point
I'll look into the 27" equation. Get back to you on that.

[stules]

But adjusting the CM length does nothing different because you're equation for calculating the points involved inches, ie. 27*2.54

Not sure about that 27. I don't have that number in any equations at all. Just the length that you nominate in the blue box. Its then halved as the basis for the mid balance point.

If you have modified the sheets equations after unprotecting it, you can always download it again.

[Duzza]

Originally Posted by stules

0.3 is 3mm ie 1/8" ie 1 point
I'll look into the 27" equation. Get back to you on that.

Wouldn't it be 0.3175 then?

[stules]

Yep it would indeed. My mistake.

[mareli63]

I notice in Steve's spreadsheet one field called "balance" and one "pro balance". What is the difference between these 2? When I do the Safin setup which is 6.6 HL what balance should I consider? the pro balance or the normal balance
Thanks,

[palikero]

Originally Posted by Amone

The fourth whited-out box in that section, labeled 'Weight 1 Mass,' you can enter just about any number lower than the total added mass in grams. If you're not sure how much mass you're adding the spreadsheet provides you with that piece of information. What this is, is the amount of weight to add at the first spot, or 'location 1.'

If either value for 'weight location' comes out as greater than the total length of your racquet, you need to modify your input 'Weight 1 Mass.'

Amone, so make this simple for me, in plain English.
Where on the racquet is Weight 1 Location? (Like, how many inches up from the end of buttcap is it? Is Weight 1 Location on the handle?, on the throat?) ... Same question for Weight 2 Location...

Once I locate on the racquet where Weight 1 and 2 Locations are, I am suppose to add Weight 1 Mass amount of lead tape (in grams, I assume) to this point?

So confused.

[Amone]

The first answer I'll give you isn't an answer at all. The formula's a waste. Doesn't work. It's wrong. I've been working on a new one, but having gotten this close and failed, it's a little difficult.

The second is that whatever answer you get in the box marked 'weight 1 location' and 'weight 2 location,' divide them by 2.54 to get the number of inches from the butt cap they are. In they're current form, they're the same number, but in cm.

[jace112]

spreadsheet is no more available

[Amone]

It didn't work anyways, Jace. I'm sorry. As much as we disagree, if you'd like I can get back to work on it for you. If you want the non-working version, then I could send it to you if you'd like. soulcutterx13@yahoo.com

EDIT: Never mind, I'm trying to fix it anyways. For a second there I sounded kinda pathetic! ^_^;

[jace112]

Originally Posted by Amone

It didn't work anyways, Jace. I'm sorry. As much as we disagree, if you'd like I can get back to work on it for you. If you want the non-working version, then I could send it to you if you'd like. soulcutterx13@yahoo.com

EDIT: Never mind, I'm trying to fix it anyways. For a second there I sounded kinda pathetic! ^_^;

Yes, we sometimes disagree, but it was just to improve our knowledge

I'm also doing some kind of SW and other tennis tools spreadsheet, I was looking for some Trav's formulas (SGPR...). I'll post this tool next week. And maybe we'll merge our files?

Wish you the best for 2007

jace from Paris

[Amone]

Originally Posted by jace112

Yes, we sometimes disagree, but it was just to improve our knowledge

I'm also doing some kind of SW and other tennis tools spreadsheet, I was looking for some Trav's formulas (SGPR...). I'll post this tool next week. And maybe we'll merge our files?

Wish you the best for 2007

jace from Paris

Same to you, Jace. I do have most of those formulas available, if you'd like I can post them here.

[jace112]

THX! here's my email address : jace_dehodossy (a) hotmail.com

[gd!]

Originally Posted by stules

Hi
I have taken a few of the formulas that have been on various threads lately,
and combined them into a more more useable format.
Thanks to all that contributed. Instructions are included particularly Travlerjm, Amone, and TonyB. Should be self explanetory.
I hope this helps............
download it here
http://www.badongo.com/file/1604939
You have to go to the bottom of the page, and read the instruction.

I figure you have Excell on your pc.

open the spreadsheet.

There is no need to copy the formula. Across the bottom of the page are 'tabs. I have inserted about 10 popular racquets there, with the specs off TW. click on the tab, and mod away to your hearts content.

When you wish to use a new racquet,
'right click' on any tab at the bottom of the page,
click 'copy sheet'
tick the sheet you wish to copy
'ok'
'right click' on the new tab and rename to the desired name.

The blue fields need to be filled out, ie if your racqet length is 69.5cm, you need to insert that number in the blue square.

Fill out the blue 'weight added' squares with grams of lead at a distance from the butt (both figures can be varied) but leave the space blank or with a '0' in it if you don't place lead there. Negative numbers work as well, eg if you trim down the grommets, weigh them before and after, and place the difference as a minus figure at the average distance from the butt where you trimmed.

TW's figures are close, but they are averages of that racquet, and not for your specific one. ie if you have a 4 5/8 grip it may be heavier, and slightly more head light. With this in mind I weigh the actual racquet I am modding, measure its actual balance point (with overgrip and dampener on) and check the SW using the pendulum method (as per the bottom of the spreadsheet) and then insert these figures into the start of the spreadsheet instead of TW's. Either way is reasonably close.

Please follow these instructions, and hopefully it will be reasonably self explanatory. If you have any difficulties, please say so, as you won't be the only one. I have tried to label everything on the spreadsheet to make it useable without complicated instructions.

PS, I don't think there are any mistakes, but caveat emptor...
Regards Stuart

Hi, unfortunately your link and file is no longer available. Appreciate if you could mail it to me --> go_deep@web.de

Thanks!