**Short Answer**
Yes it's a real thing. Thinner sponge can *sometimes* result in far more speed (than you would otherwise normally get), if teamed with a Hinoki blade.
All that being said, here come the disclaimers:
- it depends an lot on the particular blade and rubber involved,
- the amount of extra speed you get varies widely, depending on the combined density and overall elastic potential of both sponge and blade,
- the results you get with this method can (and do) vary widely as a result of all the above,
- it's typically a tricky situation to try and get all the various factors 'just right' so you end up seeing the desired speed boost, and...
- the particular blade/rubber combo you describe is far from the only (or the best) way to see this particular phenomenon in action.
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**Much Longer More Detailed Answer:*"
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Most of the time, these kind of claims are referring to a physics phenomenon I call 'blade effect', for want of a better term (it's a highly misleading term IMO that was first coined by 729 ages back, but I still use it here anyway, as nothing better at describing the necessary physics seems to have been invented yet).
Blade effect basically refers to an extra "kick" of rebound speed that a blade can add to your strokes, thereby making your shots faster than what your rubber should theoretically otherwise be able to provide.
Blade effect often *feels* most pronounced when thinner sponge rubbers are combined with Hinoki blades (especially one ply blades), as this combination of blade and rubber allows blade effect to be detected far more clearly (this is not however the ideal way to achieve it... More on this later).
You can usually get some level of blade effect out of almost *any* blade, depending on the rubbers you've attached to it. You don't need to use Hinoki per se, It's just a lot easier to create the effect while using a super springy wood like Hinoki.
Blade effect is the reason why some specific rubber and blade combinations really 'click' well together and just feel fantastic (it's also the reason why others rubber / blade combos never quite gel properly and just feel kind of 'off'.)
With blade effect, rubber and blade synergistically become more than the sum of their parts, and perform better as a team. They are basically feeding off each other, and helping each other out more
When lots of blade effect is present between rubber and blade in your set up, other 'better and typically more expensive rubbers' can sometimes feel a bit dead and lifeless in comparison when strapped to the exact same blade.
I've meet hosts of players over the years who have found that for them personally, "Rubber A" performs better, and feels faster on their normal blade that Rubber B does ...even though on paper, Rubber B may be a far better product.
In most cases, they can have trouble pinpointing exactly why some rubbers just perform a lot better on their blade than other similar ones do.
The answer in my experience typically comes down to how much blade effect is present in their set up, (though there may be other factors at work too).
Blade effect, is basically a function of the relationship that exists between your rubber's average density & elastic potential on one side, and the density / hardness / elastic potential of the wood in your blade on the other.
Sponge thickness plays a part in this relationship yes, but the respective density and elasticity present in both your rubber and blade (and how they interact) matters far more than rubber thickness.
In its simplest terms, to create good blade effect, your playing rubber has to kind of 'partially bottom out' a lot during play... with emphasis on the word 'partially'.
To create blade effect, **just the right amount** of impact forces from ball hitting rubber, has to pass through the rubber completely and reach the outer surface of your blade.
"Regular" bottoming out tends to slow your shots down, as the hard surface of your blade stops your rubber stretching, and this limits the amount of elastic rebound it can impart to the ball.
With the "partial and synergistic" bottoming out that occurs with blade effect, the ball actually speeds up, because your blade basically starts acting like an extra layer of sponge, adding it's own catapult effect to the mix.
In this scenario, the wood of your blade blade (assuming it has just the right properties) will gets just enough impact energy from the ball, and is just flexible and elastic enough :
A: to allow your rubber to stretch and contract properly, without being hampered by the blade, while...
B: ...at the same time, adding its own inherent elastic reaction and extra energy into the mix, via elastic deformation the wood undergoes during impact, imparted by the energy that managed to reach the woods surface.
While this sort of reaction happens to some degree during every ball impact, that occurs on every blade and rubber, the elastic reaction of the blade and rubber often partially interfere with each other a bit, and get in each other's way. ie: their elastic reactions are slightly out of synch.
Good blade effect comes from rubber and blade being similar enough to work together, stretch together, and push back against the ball together, WITHOUT interfering with each other in the process.
When this happens, your blade's surface starts acting exactly like an extra layer of sponge underneath your playing rubber.
Instead of feeling like your playing with regular 1.5mm, 2.0mm or 2.2 mm rubber glued to a hard, immobile lifeless surface, your blade and rubber push back against the ball, at the same time in a highly cooperative manner, which feels a bit like you're actually using 3mm, 4mm or even 5mm sponge.
Blade effect happens more often with Hinoki blades, because hinoki is naturally springy and bouncy -- ie: it has greater elastic potential in a blade than most other woods.During impact, the Hinoki adds it's own elastic potential to the elastic potential inherent to your rubber, and you get that extra speed.
Now then -- in the situation you described in your post, all that thinner rubber is doing, is providing less resistance to the ball's impact forces than a thicker rubber would.
More impact force reaches the wood's surface with thinner sponge, so more energy is free to be returned to the ball by the blade's elastic potential.
The whole set up feels fast and lively as a result, even though the rubber itself is only very slow...but using thin sponge isn't really the best way to do it.
Really, to get the blade effect speed boost you're after, instead of using thinner sponge (which is always inherently slower than thicker sponge), you should instead use rubbers:
- that have thick sponge,
- that are springy and linear,
- and that are bit more towards the medium-soft / less dense end of the spectrum.
Just because a sponge is thinner, doesn't mean enough energy is going to reach the surface by default.
Dense dead sponge can still block a lot of energy from reaching the blade. For example, try strapping a regular H3, or 729 Super FX with blue sponge to a Hinoki one ply and see for yourself.
Even with 1.5mm sponge, it's still not going to feel like a very lively set-up -- the sponge is just too dense to allow much energy to get through easily.
These old dense rubbers are actively designed to act as impact dampers for your blade. They never really bottom out, so very little energy ever reaches the blade's surface.
Additionally, any extra rebound energy that actually does manage to reach the wood and bounce back, is just going to be dampened again even further as it passes back through that hard, dense, inelastic sponge on its way back towards the surface... The blade still feels dead as a result.
WIth thicker, springy, lower density sponge however (as opposed to thin sponge) you're still getting lots of impact energy reaching the blade's playing surface.
Low density sponge has more air in it... so just like with your thinner sponge scenario, more energy reaches the playing surface, as there is less intervening mass between ball and wood.
But in my scenario with the thicker less dense sponge, you're also not lumbered with trying to get more speed out of a thin sponge... You're still using thicker sponge, which always has higher net elastic potential and greater inherent speed to it than thinner sponge does, simply because there's more of it.
Granted, some softer low density sponges are inelastic, and feel downright 'mushy' to play with.
These rubbers are great at absorbing impact energy, but lousy at returning it, because the sponge simply isn't very elastic, and doesn't want to quickly snap back into its original shape.
These sort of low density sponge rubbers actively fight against and interfere with blade effect as well, as they prevent energy from reaching the blade's surface, and should therefore be avoided if you're seeking that extra speed (I'm looking at you 729 Top Point!).
The most efficient blade-effect combo I've personally ever seen, I discovered purely by accident, while developing up my own line of one-ply blades.
The wood I use is hugely springy and very similar to hinoki. I tried fitting the blade with regular T05 rubbers, but it really didn't feel particularly different or distinctive -- it was no faster than any regular standard blade would be, when fitted with butterfly Tenergys.
When I swapped the T05s out for a set of Palio AK-47 Blues however, the blade just went nuts! Speed and spin were off the charts, and the consensus was that the palio rubbers were clearly faster than the T05s, when fitted to this particular test blade.
Nobody in their right mind would expect AK47s to outperform T05s under normal circumstances... but here, the springiness of the blade, and the springiness of the rubber, were in perfect synch.
They pulled together, combined their elastic potential without impediment, and the ball went zooming away at bloody ridiculous speed.
They only out-performed the T05s, because their respective densities and elastic potential were a closer match for each other. The butterfly speed sponge however was just a little bit too thick and dense... The blades elastic potential wasn't engaged, not enough impact energy reached the blade, and speed was lower as a result.
Getting just the right combination of sponge thickness, sponge density, sponge elasticity, wood density, wood Janka rating (hardness) wood MOR (stiffness) and Wood MOE (elasticity), in order to get maximum blade effect with your set up, is a process of pure trial and error.
It's often (but not always) a long-term, Goldilocks-type of bat-tuning endeavor frankly, and I wish you luck with it.
The good news however, is you always know when you finally get all the various factors above 'just right', ...because your entire set-up suddenly turns into a goddamn rocket launcher.
With my one-ply blades I got lucky - the AK47s really are a gift from God when strapped to those particular blades, and using them together is just a downright hoot.
Hope all my blathering makes sense to you, hope it helps you out more that it confuses.
Further questions are welcome, best of luck with it all.
