I got a 2025 Dunlop SX 300 for Christmas and unfortunately it is extremely underspec, 273 swingweight unstrung, 302 swingweight strung. I added 6g of lead at 12 to get it to 321 swingweight, but it feels very strange to swing compared to my mostly on spec 2022 SX 300 and 2025 SX 300 tour as the weight is so concentrated. Does anyone have any experience with adding weight to the hoop of an underspec racquet to make it feel more stock/uniform? The only problem is that I don't want the static weight to be unwieldly.
Adding weight to a very underspec racquet to make it feel stock/uniform
- Thread starter Wscarthy
- Start date
I’ve matched the specs of all three to be generally the same (~321 swingweight, ~32cm balance, ~335g), but because the under spec racquet’s weight is so concentrated it feels much different to swing compared to the other two.
AmericanTwist
Hall of Fame
Add weight to the top of the grip and to the butt cap areas to get the optimal balance point.
anfield
Semi-Pro
Thicker strings are heavier and can help the weight feel more integrated. You might have to change the strings of the other two and bump up the spec a bit. Putting the lead under the bumper seems to help as well. But maybe just sell it and get TW to find one of a similar spec to the others. You will take a hit financially but have peace of mind
_FrankTheTank_
Semi-Pro
I had that on my first two ezone 98 aqua night. Bought them second hand, customized and matched with 3-3.4g of lead at 12 (estimated by looking under the headgurad and measurung the length) to 289SW unstrung.
The Racket stock had very much weight in the throat and below 3&9. It was also unstablke at 3&9, even with the lead at 12. It did not feel uniform, too muchweight centralized at two locations, no conections between.
Sold them and bought three other ez98 which just feld better from the start.
I would recommend to make the offspec one maybe one gram heavier or lower the SW (2-3 pts not more) and move weight from 12 /add weight at 2&10 or 3&9. I would start with 1.5g total. The goal is to connect the two locations where too much mass is located.
It did work on my old Ezones to a certain degree, but they became to heavy overall for me personally (I did not touch the lead under the bumper as they where professionally customized as a pair and I sold them as they are).
But if you feel that the concetrated weight at throat/below 3&9 is blocking your swing, their is not much you can do about it.
The Racket stock had very much weight in the throat and below 3&9. It was also unstablke at 3&9, even with the lead at 12. It did not feel uniform, too muchweight centralized at two locations, no conections between.
Sold them and bought three other ez98 which just feld better from the start.
I would recommend to make the offspec one maybe one gram heavier or lower the SW (2-3 pts not more) and move weight from 12 /add weight at 2&10 or 3&9. I would start with 1.5g total. The goal is to connect the two locations where too much mass is located.
It did work on my old Ezones to a certain degree, but they became to heavy overall for me personally (I did not touch the lead under the bumper as they where professionally customized as a pair and I sold them as they are).
But if you feel that the concetrated weight at throat/below 3&9 is blocking your swing, their is not much you can do about it.
Grafil Injection
Legend
With my sleuthing hat on, since 6g of weight at 12 will add at least about 21sw points, that must be the only point above the handle that you have added weight as your SW increased 19pts. But if the static weight has risen to 335g, you must have added a total of about 17.5g to the SX300 (stock 300g unstrung), so about 11.5g has been added to the handle. Like with a couple of OGs (?).
Hence, you have highly polarised your racket. You should look to spread that weight out more, and accept a lower SW if necessary. Start by spreading the 6g at 12 around the hoop. Say 2g 12, 2g 6, 1g 3, 1g 9.
Hence, you have highly polarised your racket. You should look to spread that weight out more, and accept a lower SW if necessary. Start by spreading the 6g at 12 around the hoop. Say 2g 12, 2g 6, 1g 3, 1g 9.
Irvin
Talk Tennis Guru
What is the mass, balance, and SW of the under spec racket, before or after adding mass at 12. I’m assuming you did not add weight anywhere else.
EDIT: If you know the twist weight that would also be helpful.
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McLovin
Legend
Use the TW Customizer:
You just need to add the balance points, and it will give you a couple options for where to place the lead. If one doesn't feel right, try the other.
I will say, for the record, the new frame isn't "under spec" as there are no published specs for Swingweight by Dunlop. Only unstrung static weight & balance:
us.dunlopsports.com
Tennis Racquet Customization
A tennis racquet customization tool that calculates the amounts and locations of lead tape to place in order to achieve user defined desires for end-result racquet weight, balance, and swingweight.
twu.tennis-warehouse.com
You just need to add the balance points, and it will give you a couple options for where to place the lead. If one doesn't feel right, try the other.
I will say, for the record, the new frame isn't "under spec" as there are no published specs for Swingweight by Dunlop. Only unstrung static weight & balance:
SX 300 Tennis Racket | Dunlop Sports US
Tennis has evolved. With SX you can hit with confidence. It's not just about more spin, it's about more in. Welcome to the Spin Generation.
us.dunlopsports.com
Irvin
Talk Tennis Guru
Thanks for the replies!
The unstrung specs are: 297g, 31.2cm, 273sw. I don't know the twistweight unfortunately.
Yes, you are correct that the racquet is very polarized currently, much more than my other racquets. In the handle, I added about 10g to the buttcap and an overgrip. As you suggested, I think I will try smaller amounts of weight all around the hoop and adjust the tail weight as needed.
Irvin
Talk Tennis Guru
Irvin
Talk Tennis Guru
You need to add as much weight as needed to make all rackets the same. No more no less. Unless it is impossible to add weight to your under spec racket and not reach the balance and SW you want.
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Grafil Injection
Legend
Yeah, in general Spin rackets are designed to be somewhat polarised, but not as extreme as you've done. I'd move the weight around the hoop as mentioned, and lose 6g from the handle.
McLovin
Legend
I misspoke. What I meant to say was “in addition to your weight and swingweight values, you just need to add the balance point”.
Shroud
Talk Tennis Guru
adding at 12pm is going to make it feel very different. Best to do 11 & 1 even if you have to add a tad more weight.
anfield
Semi-Pro
Does it feel more integrated into the frame, if so can you explain how so?
Shroud
Talk Tennis Guru
Yeah I suppose it can be described like that. Lead at 12 will almost always be to the side of the ball on impact so the racquet will have a tendency to twist more on impact. With it at 11 & 1 its less of an issue and one reason people do 3&9. Maybe 10 & 2 is a good choice as well.
Probably not describing it well but while I put lead at 12 I don't recall ever liking lead ONLY at 12 and now will do 11 @ 1 always before 12. Though I do end up with lots at 12.
Compared to stock the weight will be more distributed than just lead at 12 added.
I've been messing around with a number of racquets and have come to the exact same conclusions. I think you explained it perfectly - thanks!
Shroud
Talk Tennis Guru
Good to know i might not be the only crazy one. I think that is why the pros often do strips of lead that are several inches long instead of just one location. I used to do that but the lead came off and was in the way of stringing , so have been working on ways to get the lead to say on and was inspired by travlerajm going outside of the frame but he was using gorilla tape and I needed a bit more weight. So ended up at 11,12,1 locations (between the grommets and around the hoop), instead of lead going from 10 to 2 along the frame. This shows the 11,12,1 locations:
Though now its just on the top half of the frame.
I believe Dunlop conforms to industry standards, which is +/-7 mm for balance. OP’s frame is 8mm HL from Dunlop’s published specs.
The Dunlop website has 320 mm as the published spec. Not surprisingly, most manufacturers don’t publish their spec tolerances. The industry standards are usually +/-7 grams for weight (which is ridiculous) and +/-7 mm for balance.
Like I said, you should contact the retailer, who will then contact the manufacturer. Most are reasonable because they want happy repeat customers that will buy multiple frames. That’s hard to accomplish when you’re selling essentially two different frames with the same paint job.
Like I said, you should contact the retailer, who will then contact the manufacturer. Most are reasonable because they want happy repeat customers that will buy multiple frames. That’s hard to accomplish when you’re selling essentially two different frames with the same paint job.
TheNadural
Rookie
Is this right? If I take two identical rackets and add 5g @12 to one, the one with 5g at 12 will twist more from off center contact? I don’t think that sounds right, but I may be wrong or misinterpreting.
Like I said, manufacturers don’t generally publish their tolerances, but they exist. Every source I could find says Dunlop adheres to general industry standards, which I cited above.
OP said his frame’s balance is 31.2 cm. Dunlop’s website says the balance is 32.0 cm. 8 mm > 7 mm. It doesn’t cost anything to call the retailor and see what they say.
Shroud
Talk Tennis Guru
It not right exactly. It would be more correct to say it would twist more than a racquet with 2.5 g at 11 and 2.5g at 1. Its really more about the weight distribution. But i can see where what I wrote might sound like I was saying weight at 12 would make it twist more just by adding the weight. I could have been clearer.
Another way to think of it, is if the factory got it right the 5g would have been distributed throughout the frame and not just at one point. That is why its different and what I was proposing would be closer to a more distributed weight.
