If you observe carefully how a racquet is strung and the route the string takes, you might notice that the 4 tie-off knots in 2-piece stringing and the route the strings take before being tied off is a potential area for tension loss from tension creep. An unusually loose cross string at the first and final cross string is a symptom of this. Also the absence, or rather non-utilization, of "braking systems" along the path of a strung string is also a cause of tension loss. Current so-called good practices of ensuring that when two strings come out from a shared grommet they must be neat and parallel, instead of being crossed with the cross being overlaid by the main, on the outside of the frame are counter-productive. I hope you are with me up to this point. Next, a strung string, say the main string that has been strung from the middle, has a tendency to pull from the side to the middle initially, meaning tension creep or loss will be inwards oriented, at least initially. Knowing the above, there is an arguement that optimizing the locations of the tie-off knots, where possible, and if not possible because of the racquet's limitation then using such "braking systems" alluded to above, will go some way to reducing tension loss. Any thoughts on this? Or do you think I am talking nonsense?
Perhaps. Most of the stuff in my thread is based on input from Yonex Japan R&D dept on how to avoid/minimize tension loss from tie-off knots location. The bit about "braking systems" has no Yonex input, and is strictly my own which I think is an elegant solution to the inherent weakness in using grommets 8 for the two mains tie-offs.
So, you saying 1 piece 2 knots would be the best. What I think, is apply 20% more on the last string, will be no tension loss.
If you use 2-piece stringing following the Yonex pattern, you will string the main string from the middle towards the sides, with the two tie-off knots at the bottom grommets 8 after coming out from grommets 10. Have a look at the main strings on the outside rim of the frame, coming out through the grommets. The spaces under the strings between the grommets are a potential problem area of tension creep/loss. A muscle power grommet system helps but more could be done. For this, why don't we call upon the cross string for a little bit of help? As the cross string is strung after the main string, can we not use the cross string at all locations on the outside of the frame to jam the main string whenever the two come near each other? Any thoughts on this so far before I go any further? Would like some input or rebuttal.
I don't overlap the strings on the outside of the racket as there is less chance of the strings abrading against the frame's paint work. Yonex pre-strung rackets tuck the mains tie off strings through the mains running on the outside of the racket, but I can't see how this can be achieved without the risk of string abrasion. The Carltons and Brownings appear to use 1-piece, in the majority of cases, without any string overlap on the outside of the frame.
I don't see how the strings can scratch the frame's frame work if you string the Yonex stringing pattern. The overlapping occurs at specific places. They are between grommets 6 and 7, 8 and 9, 10 and 11, at the racquet top on only the side of the top starting knot. Ther is no overlap on the opposite side. At the throat end on the side which does not have the final cross tie-off knot, you overlap between grommets 12 and 11, and 10 and 9. At the throat end with the final cross tie-off knot, you overlap between grommets 10 and 11, and 9 and 7. All the overlaps are done with the cross on top of the mains, and none of the overlap crosses sit on any paint work, they sit on top of the mains, which is the whole idea here, thereby jamming them.
taneepak, by your estimate, how much tension can be lost from inappropriate tying at the knot ends? if you average that over the whole length of the string, is it still a lot? interesting that you mentioned a braking system. i think it was in the proportional stringing thread that i found a US patent on a braking system. basically on each grommet hole there is a small wedge shaped contraption that stops the string from moving. the intention of the patent is to have variable tension across the string bed, but will certainly apply here too.
I believe a considerable percentage of tension loss is from the three tie-off knots and the one cross starting knot, although all the tension loss has been blamed on tension creep. Tension creep does contribute to tension loss, but I think most of the tension creep comes from these four "leaky" knots and a little comes from real tension creep. All the racquets that I string for friends and for myself do not lose much tension over a period of two months, afterwhich I just cut the strings on my own racquets. Even those that I string for others do not lose any appreciable amount of tension over 3-4 months. FYI none of my strung racquets exhibit any loose slack on the first and last cross strings, which almost all other racquets suffer from, when the racquets are newly strung. The patent braking system you mentioned sounds interesting, and if doesn't add to the cost or the racquet weight, it could be worthwhile. My system is free and allows you to use what you have.
I believe I did touch on some special techniques to tie the knots and to handle the cross starting knot to avoid or at least reduce tension loss recently. There is no magic in these techniques, but I believe they do reduce tension loss.
there is a way to verify that tension are indeed lost in the tying process. it is quite simple. everytime you finish tightening each string, use a permanent marker to mark where each string are. you can either do it in the stringbed right next to the grommet, or on the small string segment at the outter frame between two grommet. when you are done with tension the whole racket (before knotting), examine the marks, and then tie the string end and then examine the marks again. see if there are significant difference. i tried it once but as i wasn't the stringer, it was too late when i got my hands on the racket. let us know what you find out..
I recently ordered some stuff from Gefen Sports in the UK, and when it arrived it came with a catalogue and some photocopied pages of stringing patterns and string info etc. Anyway, on one of the patterns for a Carlton oval head, a 2-piece pattern, the mains are tied off as follows: main comes out of B12 goes underneath the piece of main outside the frame between B3/B4 goes back to B5 to tie off it looks like the source for this was Carlton
