Shortly after this post (link), some whom I regularly string for started re-thinking their setups.
That was totally unnecessary. If they had been accustomed to their unique hybrids, and were playing well, why change? If it ain't broke, don't fix it!
What I intended, was only to highlight the weaker link, should an unequal gauge be used. Nothing more.
Despite that, unequal gauges CAN play well. I absolutely enjoyed the combination of very thin mains with thick crosses to compensate (link), although the durability was terrible. The impeccable feel, spin and comfort more than made up for the need to restring every few hours.
Conversely, a thick mains with a thin cross, using whatever string, usually played dead to me. No feel, no spin and no control.
There is no magical string prescription. It has always been a process to find the balance between spin, control, comfort, power and durability, which are tradeoffs.
Monday 24 November 2014
Tuesday 18 November 2014
Stringing Machine: 2-Points Mount vs 6-Points Mount
A few keen on purchasing their own stringing machines asked me the importance of 2-points mounts versus 6-points.
As with anything else, it always seem the more the better, right?
However, my experience appears otherwise.
Thinking back, I have had many rackets done by others on high-end 6-points mount stringing machines. Yet frame distortion happened. (link)
When tensioning the mains at 50 lbs on a 16 mains racket, the total stress adds up to 800 lbs (16 x 50). Each end of the racket, at 12 and 6 o'clock respectively, would be subjected to a total of 400 lbs of direct pulling force compressing the hoop together.
In my younger days, I often sat on the hoop of tennis rackets with the handle butt on the floor. None cracked. So I have good faith in my racket's construction.
But looking at the mounting posts of ANY stringing machine, can anyone believe that those posts are capable of supporting 400 lbs each?
When stringing mains, hoops often shorten from 12 to 6 o'clock and widen between 3 and 9. When the crosses were strung, the 3 and 9 often narrows back and lengthens 12 to 6 again. I saw that happen and measured it multiple times.
Moreover, other than the mounts at 12 and 6, the other 4 "mounts" are merely supporting arms not fastened to the hoop. So it functioned more like a "safety guide", to prevent the hoop from changing its shape excessively before the crosses are done.
There have also been reports of over-tightened mountings at 12 and 6 causing lots of racket squeaks during tensioning. A few experienced cracks and believed it was due to the over-tightened mounts not allowing the hoop to flex freely.
That said, I am still satisfied with my 2-points mount. YMMV!
As with anything else, it always seem the more the better, right?
However, my experience appears otherwise.
Thinking back, I have had many rackets done by others on high-end 6-points mount stringing machines. Yet frame distortion happened. (link)
When tensioning the mains at 50 lbs on a 16 mains racket, the total stress adds up to 800 lbs (16 x 50). Each end of the racket, at 12 and 6 o'clock respectively, would be subjected to a total of 400 lbs of direct pulling force compressing the hoop together.
In my younger days, I often sat on the hoop of tennis rackets with the handle butt on the floor. None cracked. So I have good faith in my racket's construction.
But looking at the mounting posts of ANY stringing machine, can anyone believe that those posts are capable of supporting 400 lbs each?
When stringing mains, hoops often shorten from 12 to 6 o'clock and widen between 3 and 9. When the crosses were strung, the 3 and 9 often narrows back and lengthens 12 to 6 again. I saw that happen and measured it multiple times.
Moreover, other than the mounts at 12 and 6, the other 4 "mounts" are merely supporting arms not fastened to the hoop. So it functioned more like a "safety guide", to prevent the hoop from changing its shape excessively before the crosses are done.
There have also been reports of over-tightened mountings at 12 and 6 causing lots of racket squeaks during tensioning. A few experienced cracks and believed it was due to the over-tightened mounts not allowing the hoop to flex freely.
That said, I am still satisfied with my 2-points mount. YMMV!
Monday 10 November 2014
Budget Strings?
The lure of fresh strings is difficult to resist. If not for its price, everyone would follow the restringing patterns of their favourite players on tour.
When sufficient unfulfilled needs arise, a business opportunity comes by. So budget strings popped up, some at merely ¼ or less the price of original brand names they claim to replicate.
Since I have yet to figure out how to grow money on trees, I jumped on the bandwagon too. Then got off. And on. And off. Multiple times. (No brands nor models will be mentioned here)
There are multitudes who "swear by" the quality of these strings. And probably an equal number who threw out unused reels.
So far, I have succumbed to cheap natural guts, syn guts, polys and kevlar. Out of about nine different strings I tried (many multiple times), I thought a few polys were not bad, playing almost 70-80% similar to the real deal.
Usually, two similar sticks were strung, one with original strings, one dud. They were rotated during play every fifteen minutes. A single new can of balls was used.
At 15 minutes, both were almost indistinguishable. At 30 minutes, significant tension loss started creeping in. At 45 minutes, control and spin departed to string heaven. Budget price for budget durability too?
The kevlar did not feel like kevlar to me. More like garden wire. (link) The syn gut was completely devoid of any feel or feedback. It gave me the impression it was strung with coaxial cable.
Buying and stringing the budget natural gut was like playing russian roulette. One batch was kinked with white fold-lines straight out the package. Could have been the shipping, so after some negotiation, I settled on 50% price for a replacement and some freebies.
Nevertheless, I strung it up at 52 lbs. And it snapped in the bag overnight, right at the kinked spot. The replacement arrived in better shape. However, my gripe was the huge variability in gauge from start to end. I think it ranged between a 15g to 17g. And it was uncoated.
As it is, my tennis game is pathetic enough. Add to that my Mr Bean styled footwork is enough to make anyone collapse in laughter. Unless I'm bent on working towards ntrp 0.0, I would be giving all these budget strings a miss.
Or I could save them for competitors who beat the crap out of me everytime...
When sufficient unfulfilled needs arise, a business opportunity comes by. So budget strings popped up, some at merely ¼ or less the price of original brand names they claim to replicate.
Since I have yet to figure out how to grow money on trees, I jumped on the bandwagon too. Then got off. And on. And off. Multiple times. (No brands nor models will be mentioned here)
There are multitudes who "swear by" the quality of these strings. And probably an equal number who threw out unused reels.
So far, I have succumbed to cheap natural guts, syn guts, polys and kevlar. Out of about nine different strings I tried (many multiple times), I thought a few polys were not bad, playing almost 70-80% similar to the real deal.
Usually, two similar sticks were strung, one with original strings, one dud. They were rotated during play every fifteen minutes. A single new can of balls was used.
At 15 minutes, both were almost indistinguishable. At 30 minutes, significant tension loss started creeping in. At 45 minutes, control and spin departed to string heaven. Budget price for budget durability too?
The kevlar did not feel like kevlar to me. More like garden wire. (link) The syn gut was completely devoid of any feel or feedback. It gave me the impression it was strung with coaxial cable.
Buying and stringing the budget natural gut was like playing russian roulette. One batch was kinked with white fold-lines straight out the package. Could have been the shipping, so after some negotiation, I settled on 50% price for a replacement and some freebies.
Nevertheless, I strung it up at 52 lbs. And it snapped in the bag overnight, right at the kinked spot. The replacement arrived in better shape. However, my gripe was the huge variability in gauge from start to end. I think it ranged between a 15g to 17g. And it was uncoated.
As it is, my tennis game is pathetic enough. Add to that my Mr Bean styled footwork is enough to make anyone collapse in laughter. Unless I'm bent on working towards ntrp 0.0, I would be giving all these budget strings a miss.
Or I could save them for competitors who beat the crap out of me everytime...
Saturday 1 November 2014
Difficulties of Hybriding Strings
Many asked for recommendations how to hybrid and pair strings.
Most commonly:
- What tensions for mains and crosses? Any differentials?
- Which string for mains?
- Which for crosses?
- What gauge?
- Prestretch?
Personally, I do not enjoy hybrids. (I have even tried tri-brids and quad-brids!) No matter what I pair together - kevlar, syn gut, multifilament, natural gut, soft poly, stiff poly, fishing line, steel wire or grass trimmer line, it was extremely difficult to balance them well.
Inevitably, one string would dominate over the other. Usually, the feel and playing characteristics of the mains prevail. Once in a while, the crosses.
I am far from solving this puzzle, but I believe it has something to do with how the strings behave at different tensions.
When pulled to 55 lbs, the amount of total stretch observed in the following strings were:
- natural gut 6~7%
- synthetic gut 9~10%
- multifilament 10~12%
- poly 3~4%
- kevlar 1~2%
The numbers were in a range due to different batches and brands.
These same strings, when pulled an extra 10 lbs, bringing them to 65 lbs, yielded an incremental stretch of:
- natural gut 0.4~0.7%
- synthetic gut 0.8~1.1%
- multifilament 0.5~1.2%
- poly 0.1~0.3%
- kevlar 0%
The conventional wisdom is to string the softer string a couple pounds tighter. Using poly/syn gut at 53/55 lbs for example, would see them stretch about 3.5% and 9.5% respectively when strung.
However, during ball impact, the amount of additional poly stretch available is less than half that of the syn gut. Even though the strings are inter-weaved together, hard impacts bring the poly into deformation territories.
In other words, poly gets stretched beyond its elastic range and loses tension. Over time, the feel of the syn gut increases. (see "Impact Loss" in table below)
And that's only assuming one plays with the racket immediately off the stringing machine.
When allowed to rest from being strung at 51 lbs each, the "Actual Pre-Impact Tension" has already dropped to 30/39 lbs! This differential would only get wider with every ball hit.
Having established this, then how about we string poly higher instead? Would that help to compensate for its larger pre-impact tension loss compared to syn gut?
Probably yes. But only for a while before impact tension loss brings down the tension again. How fast this happens depends on how tightly strung it initially was and how hard one hits the ball.
Another often overlooked factor is string gauge while pairing. Many choose the same gauge for hybrids, typically 17g or about 1.25mm.
Using the same example of poly/syn gut earlier, from my own measurements, the 1.25/1.25 mm combination would thin out to about 1.20/1.13 mm.
Below pic shows a 1.40mm syn gut became 1.25mm strung.
Below shows a 1.25mm syn gut thin to 1.10mm strung.
An easy way to calculate this diameter change would be to use the percentage stretch as a proxy. A 1.25mm string with 10% stretch, usually becomes 1.13mm (0.90 x 1.25) strung.
Simple engineering dictates, the thicker the material, the stronger the support. This could be another factor why the poly mains dominate when paired with syn gut in the same gauge. Well, but many people like it, so it's their choice.
Perhaps after reading this, one could start deducing why Federer is touted to be using 1.30mm gut mains and 1.25mm poly crosses:
0.93 x 1.30 = 1.209 mm
0.96 x 1.25 = 1.200 mm
The same gauge combination of 16G gut and 16L poly for Serena Williams as well? (link) And Sharapova? (link) And Nishikori? (link)
That said, my personal preference is still a full bed of the same string. Primarily for its ease of adjustment and consistency after play. If I were to cut strings out after every hour of play, then it might change.
After all, according to the Luxilon String Analysis at the 2013 US Open (link, refer pg 6-10), more than 70% of the competitors used the SAME STRING in both mains and crosses.
Special thanks to Irvin for highlighting that report. (link)
Most commonly:
- What tensions for mains and crosses? Any differentials?
- Which string for mains?
- Which for crosses?
- What gauge?
- Prestretch?
Personally, I do not enjoy hybrids. (I have even tried tri-brids and quad-brids!) No matter what I pair together - kevlar, syn gut, multifilament, natural gut, soft poly, stiff poly, fishing line, steel wire or grass trimmer line, it was extremely difficult to balance them well.
Inevitably, one string would dominate over the other. Usually, the feel and playing characteristics of the mains prevail. Once in a while, the crosses.
I am far from solving this puzzle, but I believe it has something to do with how the strings behave at different tensions.
When pulled to 55 lbs, the amount of total stretch observed in the following strings were:
- natural gut 6~7%
- synthetic gut 9~10%
- multifilament 10~12%
- poly 3~4%
- kevlar 1~2%
The numbers were in a range due to different batches and brands.
These same strings, when pulled an extra 10 lbs, bringing them to 65 lbs, yielded an incremental stretch of:
- natural gut 0.4~0.7%
- synthetic gut 0.8~1.1%
- multifilament 0.5~1.2%
- poly 0.1~0.3%
- kevlar 0%
The conventional wisdom is to string the softer string a couple pounds tighter. Using poly/syn gut at 53/55 lbs for example, would see them stretch about 3.5% and 9.5% respectively when strung.
However, during ball impact, the amount of additional poly stretch available is less than half that of the syn gut. Even though the strings are inter-weaved together, hard impacts bring the poly into deformation territories.
In other words, poly gets stretched beyond its elastic range and loses tension. Over time, the feel of the syn gut increases. (see "Impact Loss" in table below)
And that's only assuming one plays with the racket immediately off the stringing machine.
(from Tennis Warehouse University String Performance Database link)
When allowed to rest from being strung at 51 lbs each, the "Actual Pre-Impact Tension" has already dropped to 30/39 lbs! This differential would only get wider with every ball hit.
Having established this, then how about we string poly higher instead? Would that help to compensate for its larger pre-impact tension loss compared to syn gut?
Probably yes. But only for a while before impact tension loss brings down the tension again. How fast this happens depends on how tightly strung it initially was and how hard one hits the ball.
Another often overlooked factor is string gauge while pairing. Many choose the same gauge for hybrids, typically 17g or about 1.25mm.
Using the same example of poly/syn gut earlier, from my own measurements, the 1.25/1.25 mm combination would thin out to about 1.20/1.13 mm.
Below pic shows a 1.40mm syn gut became 1.25mm strung.
An easy way to calculate this diameter change would be to use the percentage stretch as a proxy. A 1.25mm string with 10% stretch, usually becomes 1.13mm (0.90 x 1.25) strung.
Simple engineering dictates, the thicker the material, the stronger the support. This could be another factor why the poly mains dominate when paired with syn gut in the same gauge. Well, but many people like it, so it's their choice.
Perhaps after reading this, one could start deducing why Federer is touted to be using 1.30mm gut mains and 1.25mm poly crosses:
0.93 x 1.30 = 1.209 mm
0.96 x 1.25 = 1.200 mm
The same gauge combination of 16G gut and 16L poly for Serena Williams as well? (link) And Sharapova? (link) And Nishikori? (link)
That said, my personal preference is still a full bed of the same string. Primarily for its ease of adjustment and consistency after play. If I were to cut strings out after every hour of play, then it might change.
After all, according to the Luxilon String Analysis at the 2013 US Open (link, refer pg 6-10), more than 70% of the competitors used the SAME STRING in both mains and crosses.
Special thanks to Irvin for highlighting that report. (link)
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