String Construction

String construction

String construction is changing as rapidly as advances in technolgy allow. Most racquet strings have 2 main components: the core and the sheath. Some consist of a core only.
The core is principally responsible for strength, stiffness and resilience while the sheath provides abrasion protection to the core and depending on its construction can also provide grip to enhance feel.

Cores are either monofilament (a single thread of “thick” material) or multifilament (multiple, sometimes a few and sometimes thousands of threads of “thinner” material). The terms microfilament is now common and such strings visibly have hundreds if not thousands of core filaments - typically they go "furry" as they wear.
 - Monofilament is cheaper to make, more durable, stiffer, retains tension better, can be strung faster without damage, provides good elasticity & resilience at lower tensions and will not take high string tensions.
 - Multifilament is more expensive, less durable, softer, loses tension faster, cannot withstand the fast stringing processes used by manufacturers in the far east and provides good elasticity and resilience at higher tensions. Multifilament string beter emulate the physical properties of natural gut (particularly the pocket elasticity - see glossary of terms) which is still considered to give the ultimate sting performance

Sheaths are usually either a single or multiple wrap or a single or multiple braid - see diagram below courtesy of Ashaway.
 - Wrap is cheaper than braid and smoother providing less grip on the ball, is less durable and easier to string.
 - Braid is more expensive, more textured so it grips the ball providing better feel, more durable and requires more care when stringing in order to avoid string damage.
A broken fibre in a wrap can easily unravel exposing the core whereas a broken fibre in a braid tangles with adjacent fibres exposing less of the core thus providing better overall durability to the string.

The diagram on the left, borrowed with permission, from an Ashaway article on string construction, shows:

Top: a multifilament core with a multi braided sheath. The inner braid is tighter to provide more complete protection to the inner filaments of the core while the outer braid is more open to provide a more uneven surface and give better grip on the ball as used in their SuperNick XL PRO string.

Bottom: A monofilament core with a single wrap sheath.
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