Use polyester if you swing fast, hit with topspin and break strings; use multifilament if you value comfort, play at 3.5 or below, or your arm has ever complained. If you are between the two, hybrid it — poly mains, multifilament crosses.
They are different materials, not different grades
This is the misunderstanding that drives bad purchases. Polyester is not the “better” string and multifilament is not the beginner version. They are built differently and behave differently, and the right one depends entirely on what you need.
Polyesteris a single stiff monofilament, usually a co-polyester blend. It barely stretches. Its surface is slick against itself, which lets the mains slide and snap back — the mechanism behind topspin.
Multifilament is thousands of fine fibres bundled in a polyurethane matrix, engineered to imitate natural gut. It stretches substantially and returns energy elastically. Its fibres grip each other, so the mains do not slide much.
Head to head
| Property | Polyester | Multifilament |
|---|
| Control | High — low power, predictable depth | Lower — lively, balls fly at speed |
| Power | Low | High |
| Spin | High — snapback plus shaped profiles | Low — mains do not slide |
| Comfort | Low — stiff and inelastic | High — stretches and absorbs |
| Durability (breakage) | High | Low — frays under spin |
| Playable life | Short — goes dead well before it breaks | Degrades more gradually |
| Tension maintenance | Poor — drops quickly after stringing | Moderate |
| Cost per job | Low to moderate | Moderate to high |
Note the two durability rows, because conflating them is the most expensive mistake here. Polyester lasts longer before it snaps and dies much sooner as a playable string. A poly bed that has not broken in six months is not a bargain; it is a stiff, dead string bed that is worse for your arm than the day it was strung.
Which one, by level
NTRP 2.0–3.0:multifilament, or a synthetic gut if cost is the constraint. You need the free depth, you are not generating the swing speed that makes poly work, and poly's control is solving a problem you do not have.
NTRP 3.5: multifilament for most, hybrid if you are starting to hit through the court and finding balls sailing long.
NTRP 4.0: the genuine fork. Hybrid is the sensible default. Full poly if you swing fast, hit heavy topspin and have no arm history.
NTRP 4.5+: poly or hybrid. At these swing speeds a full multifilament bed is very hard to control.
The hybrid, properly explained
A hybrid uses two different strings in one frame: typically polyester in the mains (the vertical strings, running handle to tip) and multifilament or natural gut in the crosses.
It works because the two sets of strings do different jobs. The mains do almost all the sliding and snapping back, which is where spin and control come from. The crosses contribute disproportionately to how the bed feels and how much energy it absorbs. Putting the stiff string only where it is needed gets you most of the control with much less of the shock.
Ask your stringer for “poly mains, multi crosses”. It is a standard request, it costs no more than a normal restring, and it is the setup a lot of 4.0 players should be using and are not.
Tension differs between the two
An important practical point. Polyester plays stiffer than its tension number suggests, so it should be strung two to four pounds lower than you would string a multifilament in the same frame.
Stringing a poly at the tension you used for multifilament is a common and painful error: the bed is far too stiff, control becomes harshness, and the arm pays. See the tension guide.
What about synthetic gut?
A third category that gets overlooked: a solid nylon core with a wrap, sitting between the two families. It is cheaper than both, softer than poly, more durable than multifilament, and it has no standout property whatsoever.
For a club stringing dozens of racquets, or a 3.0 player who just needs string in the frame, it is entirely sensible. For anyone making a deliberate choice about how their racquet plays, it is a compromise with no upside.
The honest summary
Most club players are in a full polyester bed because that is what the tour uses and what the shop defaults to, and a meaningful share of them would play better and hurt less in a multifilament or a hybrid. Polyester is a tool for controlling a swing that is already too powerful. If that is not your problem, it is not your string.
