There's been some buzz around a tennis string company called Diadem Sports and their star-shaped co-poly string Solstice and although I was supposed to test the string already at its release last year, I forgot my set of demo strings in a hotel room in LA and then other strings and things came in the way.
Now I've tested Solstice Pro in my Prince TeXtreme Tour 95 for a couple of months and here are my conclusions:
Control is the primary feature I'm looking for in a string. A lot of strings give you control, but often coupled with arm pain due to string stiffness. Diadem Solstice Pro is definitely control-oriented yet comfortable, in my arm and mind very similar to another favorite string of mine, Solinco Tour Bite Soft. The star-shaped string really bites into the ball and delivers a predictable response. At least for the first 8-10 hours of hitting.
I think Diadem Sports has really managed to create a spin-friendly yet comfortable string. It's stiffness rating is remarkably low for a polyester string and your arm will feel it. I wouldn't hesitate to try this even in a stiffer frame such as the Pure Aero (although I personally avoid stiff racquets myself).
The point of the so called “Star core technology” is of course to create more rotations on the ball. And Diadem Solstice Pro is definitely a spin-friendly string. Does it offer more spin than Solinco Tour Bite? I would say pretty much the same. Looking at string performance in the Tennis Warehouse database, they're ranked on almost exactly the same score.
I wouldn't say that Diadem Solstice Pro is the most durable string I've ever tried, but I feel I get a few more hours out of it than the very much comparable Solinco Tour Bite Soft. The shape is fading a bit after eight hours of play and control is reduced, although not to the degree of immediately cutting it out. It is however not as durable as my two favorite strings in that department: Solinco Hyper-G and Volkl Cyclone.
Diadem Solstice Pro is definitely a must-try string if you're shopping for a polyester string that's comfortable yet spin-friendly. Together with Solinco Hyper-G it is one of my favorite poly strings at the moment.
Buy Diadem Solstice strings at Tennis Express (affiliate link)
From Diadem Sports:
What is Star Core technology?
Six equally spaced 60 degree ridges around a circular body offers the best possible combination of ball bite and minimum string to string friction. Solstice string has a larger surface area then a round or edged string with the same diameter, due to the geometric properties of a star (hexagram) shape. Furthermore, the sharp points of the Solstice string combine with the enhanced friction due to surface area for lethal bite.
Conversely, the Solstice shape allows for less friction between the cross and the main strings due to minimum contact as the points of the star interact with each other. This reduced frictions results in explosive snap back, a key component in spin generation.
This phenomenon takes place regardless of the gauge, as the edges come to the same 60 degree angles no matter the diameter of the overall string. Therefore, extreme spin is capable with any gauge of Solstice strings. Our Star Core Technology is found in all our Solstice line of strings, and is Patent Pending.