REXIS SPEED puts a monofilament component inside a multifilament string

REXIS SPEED gives a useful example of why a string label needs more than one word. Yonex places it in the multifilament category, while its US material field lists nylon, polyester and FORTIMO. The Japanese launch announcement of January 7, 2021 goes further: the centre of the core contains a nylon–polyester monofilament component. These descriptions address different levels of the same product, from the complete string to one part inside it.

The complete string and the central component

The launch explanation calls the central arrangement a sea-and-island structure. Nylon forms the surrounding sea and polyester forms the islands. Yonex presents the nylon as a rebound-oriented material and the polyester as a way to restrain deformation and sharpen response. The physical point for a buyer is the combination and its location: the polyester appears within a composite centre, while the finished product remains listed as a multifilament.

A useful product note therefore reads “REXIS SPEED, multifilament, nylon/polyester composite centre” before adding diameter. A note containing only “polyester” would discard the architecture that distinguishes this product. Equally, “multifilament” alone leaves out the centre. Keeping both fields is especially useful when a shop search filter offers only a short material category and a longer description appears elsewhere on the product page.

The same 2021 announcement describes COMFORT through another design change: it keeps the earlier REXIS basic structure and introduces a lower-friction coating. Yonex attributes smoother string movement and a softer holding sensation to that coating. SPEED’s central composite and COMFORT’s coating are two distinct parts of the design story. Their names point toward different intended sensations, supported by different construction descriptions.

What the current product sheets actually identify

FEEL broadens the comparison. Its material field adds rubber polymer and capsule to nylon and FORTIMO, and the US performance field says Control. That gives a buyer a third concrete specification to discuss, rather than treating every REXIS package as the same string with a different label. The table records the variants actually checked: COMFORT 125 and FEEL 130 also differ in diameter, which matters when planning a comparison.

FORTIMO is the polyurethane material identified in Yonex’s February 28, 2017 REXIS introduction. That explanation describes FRF, Fusion of Resin Filament, as filling gaps between nylon filaments with resin. It also describes plasma bonding of filaments and resin. The current US SPEED, COMFORT and FEEL sheets retain FRF, plasma bonding and FORTIMO in their technology fields, connecting the family’s manufacturing vocabulary with the individual material lists.

The dates are useful because the comparison baseline changes between announcements. For SPEED, the January 2021 launch names AERON SUPER 850 as the comparator and reports manufacturer gains of 5% in ball speed and 3% in string recovery speed, the latter labelled power. Those are two different stated outputs. Carry the named comparator and date with the numbers; a personal hitting comparison should record its own frame, setup and outcomes.

Choose the comparison before choosing the package

The current US SPEED 125 sheet identifies 1.25 mm and model RTGS125; SPEED 130 identifies 1.30 mm and RTGS130. Both carry the same listed material combination and Power emphasis. This offers a straightforward way to hold the model constant while changing diameter. By contrast, switching from COMFORT 125 to SPEED 130 changes both the model and diameter, so a purchase record should name both changes explicitly.

Start with the reason for changing. A player who already likes COMFORT’s response but wants to investigate SPEED’s more lively positioning can begin by matching the nominal diameter. A player happy with SPEED who wants to compare its two thicknesses can keep SPEED as the model. These are different decisions, and each needs a different second package. Write one desired change, such as easier rally depth or a more predictable block return, beside the current setup.

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For a practical comparison, give the stringer the same frame model, chosen diameter, full-bed or hybrid arrangement, reference tension and any installation preferences already used. Record the date and playing time for each installation. If the frames or installation conditions differ, keep those differences beside the observations. This turns a vague preference into information you can use for the next order without assigning every change in the shot to one ingredient.

Use a few repeatable playing situations that matter in your matches. Compare a controlled rally toward a deep central target, a compact return against a familiar serve and a short volley requiring a quiet racquet face. Record where the ball finishes and what adjustment you made. A string that helps one situation but requires a larger correction in another presents a concrete tradeoff to discuss, alongside the manufacturer’s intended feel.

Keep wear in the same record. Photograph the same part of the string bed after comparable playing time and note where surface fraying, notching or a break appears. Record the location as well as the elapsed hours. This gives the stringer something specific to inspect when deciding between another identical installation, a different gauge or another construction. A repeated break near the frame calls for attention to that location during the equipment check.

Finally, distinguish the material combination inside SPEED from a hybrid installation. The former is part of the manufactured string. The latter is your choice of one string for the mains and another for the crosses. A full bed of SPEED uses one named model throughout, despite its multiple listed constituents. A hybrid order should name each string, diameter and position separately so that the intended arrangement survives the trip from shopping note to stringing machine.

1. For product identity, record REXIS plus SPEED, COMFORT or FEEL, then the exact diameter and package code.
2. For the reason to switch, choose the response you want to investigate and the match situation in which it matters.
3. For comparison, keep the frame and installation record beside playing time, shot observations and visible wear.
4. For a repeat order, give the shop the successful complete setup; use the full construction description when considering a substitute.