which type of racket should string at which tension?

i think it depends on the construction (shape) and the material more than head lightedness/headheavyness. if you look at comparison tables, you will notice that the AT heads can all take 20-25lbs at 3U, but NS can only take 19-24lbs at 3U. BUT, i think all of the MP series and Cab series only go up to about 22lbs at 2U or 3U, so it all depends.this, of course, is based on yonex rackets. pros string just about any racket they use at around 30lbs though, so i dont think its such a huge issue with them (i dont think rackets break during professional level games all that often )

 

I strung so many cabs and MPs above 24-25 lb, and they are fine. Personally, I will say most of the models from reputable brands (in good condition) can take up to 25lb w/o any problem.

 

yep, LB is right. what i was referring to was the recommended stringing tension by Yonex, which is within the warranted range

 

I believe racquet manufacturers' recommended string tensions are based on the assumption that the racquets will be strung on the basic 2-point professional machines and the elastic properties of the frame. 2-point machines are a good test of a racquet's elastice properties, when stringing the crosses. Higher recommended tensions usually reflect better elastic properties, which is different from the more important tensile strength properties, of the frame. This could explain why higher tensile strength, but not necessarily higher elastic properties, nano racquets do not have recommended tensions significantly higher.
With 6-point machines the elastic properties of a frame are not as critical, hence their ability to string at very high tensions. The only limiting factors on such machines will probably be the string itself and the compressive or tensile strength of the frame, especially at parts of the outer frame between the grommets where the string is laced onto.

 

something i dont understand is, how does stringing machine type affect how much tension you can put on the racket? after all, when you lift the racket off the machine at the end of stringing, side supports no longer support the racket.

 

You can actually check this out yourself. Go to a badminton store and see how they string on 2-point machines. Watch carefully as they start stringing the crosses. You will notce the racquet frame "collapsing" inwards and outwards. After stringing compare the strung racquet with an identical unstrung racquet, and 99% of the time you will see a deviation. The deviation could be minor or even very obvious-the frame becomes longer or rounder or distorted in some parts-because the frame's elasticity allows for such deviation without breaking. If it breaks, the frame's elasticity limits have been exceeded. Contrary to what some people believe better elasticity, which gives you higher tension limits, does not necessarily mean better materials.
It is this elasticity, 2-point, and 6-point machines that explains why a racquet strung at say 28/31lbs can show less distortion than an identical racquet at a 20/22lbs tension.