Polyester strings have taken over club and professional tennis — and for good reason. They offer durability, spin potential, and control that no other string type can match. But there’s a catch: if you string poly at the same tension you used for your old multifilament or synthetic gut, you’re almost certainly stringing too tight.
As a stringer, this is the single most common mistake I see. A player switches to polyester from multifilament, keeps the same tension, and wonders why their arm hurts and the ball isn’t going anywhere. Poly is a fundamentally different material, and it needs a different approach to tension.
This guide will give you concrete starting tensions for the most popular polyester strings, explain why poly behaves differently, and help you dial in the perfect tension for your game. For a broader overview of tension principles across all string types, see our complete tennis string tension guide.
The Golden Rule: Drop 10% From Your Multifilament Tension
If you’re switching from multifilament or synthetic gut to polyester, here’s the simplest starting point: take your current tension and reduce it by roughly 10%.
So if you’ve been playing comfortably at 55 lbs with a multifilament, try your new poly at around 50 lbs. If you were at 52 lbs, drop to 47 lbs.
This isn’t an arbitrary number. Polyester is a much stiffer material than multifilament. At the same tension, it deflects less on impact, which means less power and more shock travelling into your arm. Dropping tension compensates for that stiffness, giving you a similar feel and energy return to what you’re used to.
Think of it as a starting point, not a final answer. But it’s a far better starting point than simply carrying your old tension across.
Recommended Starting Tensions by String
Not all polyesters are created equal. Some are softer and more elastic, others are stiff and boardy. The right starting tension depends on which string you’re using. Here are my recommendations for the most popular polys — if you’re not sure which string to choose, our guide on how to choose tennis strings is a good place to start.
Babolat RPM Blast — 48–52 lbs
The benchmark polyester. RPM Blast is a medium-stiff poly with excellent spin potential. Most players do well starting at 50 lbs and adjusting from there. It’s the string Nadal made famous, and it rewards a moderate tension where you get both control and enough power to swing freely. Available from Pro Touch at £40 installed.
Solinco Hyper-G — 46–50 lbs
Hyper-G is a shaped poly that generates huge spin, but it’s on the stiffer side. I’d start most players at 48 lbs or even lower. Stringing Hyper-G above 52 lbs tends to make it feel dead and harsh — you lose the lively snap-back that makes this string special. If you’re after spin, keep the tension modest. Available at £40 installed. See our picks for the best tennis strings for spin.
Luxilon ALU Power — 48–52 lbs
ALU Power is tension-sensitive, meaning small changes in tension produce noticeable differences in feel. This is a string where 2 lbs either way genuinely matters. Start at 50 lbs, play a set, and adjust in 1 lb increments. Many tour players string ALU Power in the high 40s for a reason — it opens up beautifully at lower tensions. Available at £40 installed.
Luxilon 4G — 50–54 lbs
4G is one of the stiffer polys on the market, which means it can handle — and often benefits from — slightly higher tensions than other polyesters. Where most polys feel boardy above 52 lbs, 4G maintains its playability. If you’re a player who likes a controlled, low-powered response, 4G at 52–54 lbs is a solid setup. Available at £40 installed.
Luxilon Element — 50–54 lbs
Element is Luxilon’s softer poly, designed to give you polyester control with more comfort. Because it’s inherently more forgiving, you can string it a touch higher than stiffer polys without the harsh feedback. A great option if you want poly performance but are concerned about comfort. Available at £40 installed.
Head Lynx Tour — 48–52 lbs
Lynx Tour is a crisp, control-oriented poly with a satisfying feel at moderate tensions. Start around 50 lbs. It’s not as stiff as ALU Power, which gives you a bit more forgiveness if you overshoot on tension. Available at £30 installed.
Yonex Poly Tour Fire — 48–52 lbs
Poly Tour Fire is one of the more comfortable polys available, with a softer feel than many competitors. Starting at 50 lbs works well for most players, and you can push to 52 if you want more control without the string becoming harsh. Available at £30 installed.
Wilson Revolve — 48–52 lbs
Revolve is Wilson’s all-round poly — reliable, predictable, and well-suited to intermediate players. It’s not too stiff, not too soft. Start at 50 lbs and adjust based on feel. Available at £30 installed.
Solinco Confidential — 46–50 lbs
Confidential is a softer, arm-friendly poly that plays best at lower tensions. Stringing above 50 lbs starts to negate its comfort advantage. I’d recommend starting at 48 lbs and only going higher if you’re spraying the ball. Available at £40 installed.
Tecnifibre Razor Code — 48–52 lbs
Razor Code is a popular co-poly with a firm, controlled feel. It responds well to the standard poly tension range. Start at 50 lbs. Note: we don’t stock Razor Code, but you’re welcome to bring your own string and we’ll install it for £20.
Kirschbaum Max Power — 46–50 lbs
Max Power is a smooth round poly that plays well at lower tensions. It’s not the stiffest string, so keeping the tension in the mid-to-high 40s lets it perform at its best. Again, bring your own and we’ll string it for £20.
Why Polyester Needs Lower Tension
The physics is straightforward. Polyester is a stiff, low-elasticity material. When a ball hits a string bed, the strings deflect and then snap back, returning energy to the ball. With a soft, elastic string like multifilament, the strings deflect easily — they act like a trampoline. Polyester deflects far less.
At the same tension, a poly string bed returns less energy to the ball than a multifilament string bed. You’ll feel this as a lack of power and a “dead” sensation. The solution? Lower the tension. This allows the stiffer strings to deflect more on impact, restoring some of that energy return.
There’s also the comfort factor. Higher tension with a stiff material means more shock is transmitted to your arm on each shot. Dropping tension softens the impact, reducing the risk of elbow and wrist problems over time.
How Tension Affects Poly Performance
Getting the tension wrong with poly is more punishing than with other string types. Here’s what happens at the extremes:
- Too high (above 55 lbs for most polys): The string bed becomes boardy and harsh. You’ll feel excessive vibration, lose depth on your shots, and your arm will tell you about it after an hour of play. There’s very little benefit to stringing most polys this tight.
- Too low (below 40 lbs for most polys): The string bed becomes trampoliney. You’ll generate plenty of power, but controlling the ball becomes difficult. Shots sail long, and you lose the precision that poly is supposed to provide.
The sweet spot for most players and most polyester strings sits between 44 and 54 lbs. Within that range, you’re balancing power, control, comfort, and spin in a way that poly does best.
Adjusting From Your Starting Point
The tensions above are starting points. The only way to find your ideal tension is to play with it and adjust. Here’s a simple process:
- String at the recommended starting tension for your chosen poly.
- Play a full set or practice session. Don’t judge after five minutes — give the strings time to settle and give yourself time to adapt.
- Assess how the string bed feels:
- If the string bed feels harsh, stiff, or dead — drop 1–2 lbs next time.
- If you’re spraying the ball or struggling for control — raise 1–2 lbs next time.
- If it feels comfortable and your shots are landing with good depth and control — you’ve found your tension.
- Make one adjustment at a time. Change tension by 1–2 lbs between restrings, not 5 lbs. Small changes make a real difference with poly.
Your racquet matters too. A stiffer frame (RA 68+) paired with a stiff poly at high tension is a recipe for discomfort. If you’re playing with a stiff racquet, err on the lower side of the recommended range.
Tension and Spin
One of the biggest advantages of polyester is spin generation, and tension plays a direct role. At lower tensions, the string bed deflects more, allowing the main strings to slide across the crosses and snap back into place. This snap-back effect is what generates topspin — and it’s more pronounced at lower tensions.
If you’re a player who relies on heavy spin, you’ll generally benefit from stringing on the lower end of the recommended range. Many competitive players deliberately string their polys in the mid-40s specifically for this reason. For more on maximising spin from your setup, read our guide to the best tennis strings for spin.
Pre-Stretching and Tension Loss
Here’s something many players don’t account for: polyester strings lose tension faster than any other string type. Most polys drop 10–15% of their reference tension within the first 24 hours after stringing. After that, the tension loss slows but continues steadily.
What does this mean in practice? If you string at 50 lbs, you’re probably playing at around 43–45 lbs within a day or two. This is normal, and it’s one reason why poly shouldn’t be strung too tight to begin with — the tension you play at will always be lower than the tension on the machine.
Some stringers pre-stretch polyester to reduce initial tension loss. This can help the string hold its tension more consistently, but it also slightly changes the feel of the string. If your stringer offers pre-stretching, it’s worth trying — just be aware that you may want to increase your reference tension by a pound or two to compensate.
Regardless of pre-stretching, poly strings should be restrung regularly — the tension loss compounds over time, and a dead poly is arguably worse than a dead multifilament.
Find Your Perfect Poly Tension
Getting your polyester tension right can transform how your racquet feels. Too many players struggle with poly because they’re stringing too tight, missing out on the comfort, spin, and power that the right tension unlocks.
If you’re in East London — whether you’re based near Mile End, Hackney Wick, or anywhere nearby — book a restring and we’ll talk through the right tension for your string and your game. We stock a wide range of polyester strings from £25 to £40 installed, or bring your own for just £20.
Want to discuss your setup first? Drop us a message on WhatsApp — we’re always happy to help you find the right tension.
