Why a String Always Breaks in the Same Place

Where a string breaks tells you more than when it breaks. A racket that fails in the same spot every time is rarely a string problem and rarely too much tension — it is usually a grommet that has stopped doing its job at that hole.

Nobody checks this when buying. The grommet is the small plastic tube lining each hole in the frame, priced in fractions of a cent, fitted at the factory, never sold separately, and described in the spec sheet with a single word. It also decides whether a string set survives to a natural death.

The string is cut at the hole, not broken in the middle

At impact the string’s deformation concentrates at the inner edge of the hole. It exits through the frame, turns back outside, and re-enters at the next hole — and that short section flexes on every shot. With a healthy grommet, the bend is wrapped inside a rounded tube and the string never touches carbon.

Once the tube wears through, the string sits directly on the edge of the carbon wall. That edge is hard and often retains a sharp lip from moulding, and a string flexed over a sharp lip a few dozen times will fail. This is why the break sits one or two centimetres in from the frame edge rather than in the middle of the sweet spot.

Our STORM CC6.0 lists three things together: 76 string holes, nylon 12 grommets, 11 mm beam. They only mean something as a set — hole count sets the spacing, spacing sets the bend angle at each hole, and the grommet material sets how long that angle can be survived.

Three ways a grommet fails

A grommet does not snap the way a string does. It degrades through three stages, each with a different symptom.

Worn through. The lip is cut away on one or both sides, exposing the carbon underneath. The string still plays, but its life is now counted in weeks rather than months. Test by slackening the string and running a finger along the hole — a hard edge means it is gone.

Flattened. Not worn through, but crushed under sustained tension until the bore narrows and grips the string. The symptom is unusually fast tension loss — a fresh string job goes soft within a week — with no visible break point. This is the hardest to diagnose because the grommet looks intact.

Popped out. The tube has left the hole entirely, leaving bare carbon. Most common on the outer face of the frame, where the string then runs straight over the wall. The most dangerous of the three, because failure tends to arrive mid-match.

Nylon 12 (PA12) is the usual choice because it combines abrasion resistance with recovery: crushed, it regains part of its bore rather than deforming permanently the way plain PE does. A real material difference, not a label — with a limit. After twenty to thirty restrings the set is aged out and should be replaced.

More holes does not mean better

76 holes is the common badminton count; 72 also exists. More holes means shorter spacing, more continuous support around the edge of the bed, and a sweet spot with a little more room to spread. The cost is a sharper bend at every hole — the string has to turn further within a shorter span, which wears the grommet faster.

So “more holes is better” depends where you stand. For a player it buys edge forgiveness. For a buyer or a stringing shop it means more service points, faster wear, longer inspection per restring.

The real variable is not hole count but whether the hole mouth is chamfered. Two frames with the same 76 holes behave differently if one has a radiused transition at the mouth — stress concentration at that edge drops noticeably. It never appears in a spec sheet; you see it on a sample or you ask the factory.

Gauge against hole mouth

Thinner string means higher pressure at the hole. The same tension over a smaller cross-section produces more force per unit area.

Our range runs from 0.66 mm to 0.72 mm. BG66 is 0.66 mm at a 22–24 lb ceiling, BG95 is 0.68 mm at 26–30 lbs, and BG2006 is 0.72 mm. Fine string plays crisp and elastic but demands more of the grommet — at identical hole condition, 0.66 mm will fail before 0.72 mm.

So gauge is not a feel decision alone. Fine string in an old frame stacks two uncertainties. Pragmatic rule: where grommet age is unknown, start at 0.69 mm and move up after the set is replaced.

Four questions that settle it

Grommets never make the sheet, but four questions lead to action.

Is the grommet replaceable, and is there a spare part? A one-piece moulded strip is expensive to renew; segmented strips are cheap but pop out. This decides whether after-sales can repair at all.

What does the material actually say? “Nylon” is a category; PA12 or PA66 is a specification. No grade named usually means a generic compound.

Is the hole mouth chamfered? Ask for a magnified photo of the mouth. This is not something a factory can fake.

Hole count against beam width. 76 holes with an 11 mm beam is one engineered pair; change the beam and the count has to be recalculated rather than copied.

How to put this into practice

Put all four into the structural block of your RFQ, next to the tension ceiling. The reasoning is simple: the ceiling is what the material claims, and the grommet is the condition under which that claim holds. A frame rated to 28 lbs whose grommets wear through in three months cannot actually sustain 28 lbs in daily use.

For stringing-shop customers, add one line to the listing: factory grommet material and hole count, so they can stock the right spare. It costs nothing and removes a recurring complaint — when a customer says “it always breaks in the same place”, the answer is usually written there.