A new approach to string tension?

Foreword:
What I'm putting forward here is anecdotal. That said, I'd ask that people refrain from saying "That's impossible, and here's my linear mathematics on why"; I see this a lot on BC, where people try to explain why something must be true or false using very simple terms. It's often a reductionist view to support existing ideas on why something must be, rather than accepting there may be a factor unaccounted for otherwise. Keep an open mind.

Conventional theories (in simple terms):
Trampoline Effect:
The trampoline effect suggests that at lower tensions, the strings can flex more before they return to their original state. Flexing more results in hhigher energy stored.

Potential Energy
Potential energy suggests that there must be some alignment between a player's swing, and the tension they play at. A tension that matches their swing style and speed will result in the best energy storage. A tension can be too low for a player, where they flex the strings too much, or too high for a player, where they cannot flex the strings.

My theory:
I often subscribed to the potential energy theory, but I've been wondering lately why neither theory seemed to really account for all circumstances I've played under.

My theory in a nutshell suggests:
When strings are of equal qualities, thicker strings will play better at lower tensions, based on the stability of the string bed when flexed.

String bed stability:
When a string bed is unstable, the strings move in unintended ways - for example, lateral movement on the mains whilst performing a shot such as a smash. When we think of potential energy stored, we think about in linear terms - what is deformed must reform, in this case, string stretching backwards and then back into position. If the string moves out of the way, something must be occurring that does not result in the optimal amount of energy being transferred; it is either not efficiently deforming (moving out of the way rather than stretching), or in its reformation, it is not transferring power in the desired direction.

So what does this have to do with string thickness? Friction. Thicker strings have more friction than thinner strings. This means at lower tensions, there is more contact area between mains and crosses to help keep the stringbed stable and in the same position through the shot, ensuring a better transfer of power.

So why wouldn't thicker strings always be better? There's more material, making them harder to deform on the whole. This means at higher tensions, deforming a thicker string takes more effort than deforming a thinner string. We are talking of strings of equal qualities, so we're imagining Li Ning No.1 vs Li Ning No 5 (and producing the same string in different thicknesses has become more of a trend lately).

Thick strings have greater stringbed stability at lower tensions, making it easier to transfer force directly into a shot. Thin strings are easier to deform, but require higher tensions to maintain their stability.

So why have different strings at all?
Power, control, and feel will not be equal. This theory does not suggest that Li Ning No.5 at 22lbs will be better than Li Ning No.1 at 27lbs, rather, LN5 may be preferable to LN1 at 22lbs because the additional string friction makes the stringbed more stable.

For a long time, Yonex were the only real competitor for performance quality strings. Li Ning and Victor made some strings, but they had low wide scale adoption. Yonex typically make a string, rather than a line of strings; where you have Ashaway ZM62F, 66F, and 69F which are largely similar in their properties, Yonex only makes BG66UM, or Aerosonic, or BG80. Yonex's strings are more unique, in that there is only one thickess for a set of properties.

With that in mind, what are YY's most popular strings? BG80, 66UM, and 65/65Ti. In recently times, Aerobite, but I want to cover hybrids separately. YY have never really pushed to make a 'thin 65Ti', or 'a thick 66UM'. 80 is perhaps, even today, one of the most stable stringbed choices. 66UM is widely renowned as a popular performance choice, but known for its poor durability. 65Ti is an incredibly popular string amongst casual and professional players. None of these strings are comparable, really, in terms of their properties (such as core, friction etc).

Until we started getting thin and thick versions of the same string, something Yonex hasn't readily done, we only really had an apples and oranges comparison. We could compare BG80 with 66UM or 65Ti, but they are so wildly different that we could never firmly say what it is about the string bed that makes it the 'most playable'. We never had the opportunity to say why a thicker string was a better choice than a thinner string, or vice versa.

Hybrid strings:
Hybrid strings increase the string bed stability of the thinner string accompanying it. The stiffer main string allows for more stability than normal string options, which can help to make power more accessible. However, the crosses do not provide better stability for the mains as we might see in a string like BG80; this results in BG80 having better stability at lower tensions. Note, that having tried ABBT, I can also say that ABBT has much better stringbed stability than regular Aerobite.

Friction, friction, friction:
Not all strings are equal. If we consider strings with relatively similar thickness, such as LN No.1 and Gosen G-Tone 5, then at lower tensions the rougher version will have better stringbed stability. They bite into themselves more, making the strings less likely to have unintended movement.

Skill vs Power
When the smash speed of players was studied, they found the players that could hit most consistently hit the best smashes. It is possible for a player to possess a lot of skill, whereby they are very consistent, but not a lot of power - this is also true in reverse. We have some very physically strong players on here that don't have the skill of a professional player.

If you're constantly finding your stringbed has moved (with strings being bowed outwards by your shot), then you may have a gap in power and skill that does not suit your current string choice for the best stringbed stability.

Again anecdotally - and I am not the strongest physical player by a long shot - but if I used something like Li Ning No.1 at 22lbs, I would constantly find my strings displaced/bowed outwards. That would say to me, that my power is too high for the string bed. If I move up to LN No.1 at 26lbs and decide I can't access that power in out of place positions, then I have a serious gap. What if I change to 24, and I still find my strings heavily displaced? Well then, the stringbed stability isn't suitable for the alignment of my power and skill, and I'd be better off choosing a string that has greater stability at lower tensions.

(EDIT) Settling:
Stringbeds naturally settle over time. In fact, most stringers on here will vouch for letting a racket sit for a day or two after being strung. I believe that as the strings bite into each other and settle, this too increases stability, increasing the the playability of a stringbed. This may be especially true of strings that truly bite into itself, such as BG80.

Other factors for consideration:
There are a number of other factors that could influence stringbed stability:

• Racket head shape
• Width and angle of grommets
• Stringing pattern (Is it 72 holes? 76 holes? 3+2? 4+2?)

These may attribute to the feel of the racket/stringbed, but are difficult to account for overall.

Conclusion:
This does not discredit previous theories, rather, seeks to evolve on them given newer trends. You will still require the power to flex a string, and the skill to do so consistently.

Thicker strings perform better at lower tensions.
Hybrid strings perform best at mid-high tensions. (Est. 23+)
Thin strings perform best at high tensions. (Est. 25+)

Therefore, if you know you do not have the skill requirement to play with your racket strung at 29lbs, but you have the power requirement, you might consider using a thicker string at lower tensions. The thicker string will give you higher stringbed stability for when you're using more powerful shots, but still be forgiving enough to account for your skill level.

 

I'll let you know when I have the facilities to remotely test it :'D

It's no better founded nor proven than the previous theories, just asking that people don't start telling me about YM etc because that really does depend on the force being applied in 1 direction.