Polyester Tennis Strings

Because natural gut tennis strings and nylon tennis strings tend to break frequently, other strings that are more durable have made their way into the marketplace.

Polyester strings  resist notching where the main and cross strings overlap and therefore last longer than nylon strings. Some estimates state that polyester strings may last up to 3 times as long as nylon strings.

But, polyester strings are stiffer than nylon strings. This stiffness explains the increase in durability but also contributes to less elasticity and less playability. And, pure polyester strings like the Polystar Classic or the Kirschbaum Super Smash tend to lose their tension quite quickly. This loss of tension results in  a loss of control. 

During  the last few years a great deal of research has gone into trying to overcome this loss of tension and elasticity that have been the weakness of polyester strings.

Polyester is usually extruded as a single thick filament. Tennis strings made from a single filament are called monofilament strings.

A Belgian company called Luxilon has become a leader in the polyester string market.

Luxilon manufactures the Big Banger Alu Power string. This string has become extremely popular on the pro tour. Although Big Banger Alu Power is a monofilament similar to a typical polyester, it is actually a poly-ether-ether mixed with fluorocarbon. According to Luxilon, characteristics of Alu Power include no noticeable tension loss, less plastic deformation than pure polyester strings, and durability. These characteristics result in astring which retains its playability until it breaks.

Because of the increased stiffness of polyester strings there has been a  concern that this stiffness could lead to arm problems in some players. Thus, it is usually recommended that rackets strung with polyester strings be strung about 10-15%  lower in tension than they would be with nylon strings. 

Another very stiff but durable string is the kevlar tennis string.