I said I'd do this for a while now, and since I'm up and bored I'll do it now.
There have been many (and I mean MANY) questions about adding lead tape and so on. Their effects, their benefits, suggestions on locations, and so forth.
In this thread, I have posted most of my knowledge on the subject, some of which I will reiterate here.
I will try to outline most of the information to simplify the reading and understanding process. I'm not the best writer (English is my worst subject and "basic math" is my best), so it still might be a bit foggy. So feel free to ask questions for clarification. Hopefully I won't be the only one to answer because that would put a heavy burden upon myself to constantly check here and answer everything. With this, I can also easily edit information should I learn anything new or a previous conception be wrong (I am human after all). Hopefully all edits will be for the former reason, not the latter.
I might also edit this from time to time just to reorganize the information and make it more readable, because I'm too lazy to do it on the first go. So let's begin shall we?
I) General Lead Placement Locations:
) 12 o'clock (top of the hoop) - Lead at this location improves power and plow through more than any other location.
) 11&1 or 10&2 - Improves power and plow through significantly but also increases stability slightly.
) 3&9 o'clock - Improves power and plow through and increases stability by the maximum value.
) 6 o'clock - Improves power and plow through slightly.
) Throat or handle - Improves power and plow through very slightly. Generally used as counterbalance locations. (Lead on the handle is placed UNDER the replacement grip.)
) Buttcap - Used as a counterbalance location.
II) General trends based on placement:
) The farther away from the balance point you add weight, the more dramatically the balance will chance in that direction. Also, increasing the amount of weight added at that location will also increase the change in balance. Basically lead at 12 changes balance towards head heaviness most dramatically. However, 1 gram at 12 won't do as much as 10 grams at 3&9. By the same token, lead in the buttcap changes balance towards head lightness most drastically. And 10 grams at the top of the handle has more effect than 1 gram in the buttcap.
) The higher you add lead, the greater the increase in swingweight. Anywhere from where your dominant hand is located and lower has either negligible or no effect on swingweight.
) Where you add weight affects the "sweetspot". For example, lead at 12 drags the sweetspot up, while lead on the handle drags the sweetspot down. This is also a change that changes more dramatically based on how much weight and how far it is from the sweetspot. This is why players rackets have tiny sweetspots, as they have a general trend of having very headlight balances. Also, weight on the sides of the sweetspot stretches it. So lead at 3&9 basically makes the sweetspot a little wider, adding forgiveness.
III) The Two Different Setups
This is the real juicy part of the post. Generally on the tour, there are 2 types of setups. Most advanced setups will be geared into the "Swingweight 2" range. Now what does SW2 mean? Basically, when you add weight, the racket will produce more power, resulting in more depth. As you add weight, the ball goes closer and closer to the baseline when you hit it. Finally, you get to the point where the ball barely lands in every time. This is swingweight 1 status. As you keep adding lead to that, the ball starts going long. Eventually, you reach the amount of weight that the ball won't go any farther. If you keep adding weight, your swing will be slowed down and the ball will land shorter and shorter as a result. Eventually, it comes back to landing inside the court. This is swingweight 2 status. Pros who use heavy rackets are usually using rackets in the SW2 range like Djokovic, Sampras, and Murray's old racket (I'm not sure what he's using now, but he supposedly uses less weight now). The SW2 range varies based on the player's physical strength.
) Depolarized Setup - Basically, this setup has the most stability and power. Weight will generally be added lower on the racket, resulting in a lower increase in swingweight per gram. This means you can add a LOT of weight, and still not exceed your SW2 range. More mass means more stability and power. Usually the added power means a higher tension is required to control it.
---1) Examples of users of this setup: Sampras, Djokovic, Agassi, Courier, Edberg, Becker, Connors, and Blake.
---2) Types of players supported:
------a) Aggressive Baseliner - Blake, Roddick, Lendl
------b) Big Server - Roddick, Becker
------c) Counterpuncher - Agassi, Hewitt
------d) Serve and Volleyer - Sampras, Edberg
------e) Big-Hitting All Court Player - Sampras, Becker
------a) Increased stability
------b) Increased power and plow through
------c) Increased forgiveness
------d) Heavier shots off the racket
------e) Increased control
------f) Better volleys
------g) Better returns
------a) Tends to flatten out your stroke a little
------b) The excessive power requires higher tensions to control
shows how to create this setup. Basically, you add lead to 3&9 to improve stability and power, then counterbalance it with weight somewhere on the handle. The above link supplies an equation to find your ideal counterbalance location given a specific amount of weight you want to add and a specific balance you want. Of course, you can do that yourself without that equation, it's not all that hard. Most people on this board like to apply counterbalance weight for this setup at 7 inches above the buttcap. Why? Don't ask me, but a lot of people like it. There have been multiple theories such as the location is equidistant from the balance point compared to lead at 3&9, that it's the perfect distance away from the hand such that it doesn't hinder mobility much and offers the best amount of power as a result of the combination of mass and mobility.
) Polarized Setup - This setup provides the most spin and power at a given weight. Nowadays, as the game moves towards a more spin orientated game, this setup has become increasingly popular. Because a majority of the added weight is placed towards the poles of the racket (at 12 o'clock with counterbalancing in the buttcap), the SW2 range is reached more quickly, resulting in a low static weight racket. However, as a result of the lower static weight (less power from mass) and increased spin production, lower tensions are usually required to make up for the overall lack of depth and power (which further assists in spin generation).
---1) Examples of users of this setup: Nadal, Federer, Wawrinka, Safin, and Rafter.
---2) Types of players supported:
------a) Any player that relies on using heavy spin - Nadal, Federer, Wawrinka
------a) Most added power and plow through with minimal weight added.
------b) Increased spin potential (heavier spin shots off the racket)
------c) Increased consistency for baseliners
------a) Requires the use of heavy spin to control trajectory of your shots
------b) More difficult to volley with
---5) To create a polarized racket, basically add weight at 12 (you can use long strips that go from 10 to 2 o'clock or longer, or short strips layered at 12) then counterbalance with weight in the buttcap. Sometimes you might feel that you're lacking in stability, so add some lead at 3&9 to fix that. Nadal uses 9.5 grams under the bumper and 2.5 grams in the buttcap. Federer adds a little lead under the bumper to a hand-picked, stock [K]Six.One Tour (now, perhaps to a hand-picked, stock BLX Six.One Tour).
) Final notes: Do you have to use one setup or another? No. Not even all pros fall into one of these categories or another (at least, not purely). Not even all pros use racket customized to SW2 status (Verdasco comes to mind). Like in the polarized setup, I suggested that if you required more forgiveness and stability that you add a little lead at 3&9. You can combine setups. Safin had quite a bit of lead at 12, and in addition had strips at 3&9 (though less than at 12; I have no idea about what he does for counterbalancing, if anything). Do you need counterbalancing? No. But should you? Probably use at least a little. Use whatever you feel works best for you and don't be afraid to tinker with it a little. However, you want to write down the setup you like so should you experiment from there, you know how to go back to it. You want to write down the placement locations, amount of lead added, and the overall specs.