When a rubber is finished

Section 7.5 described the signs that warn a rubber needs changing: loss of grip, falling liveliness, marks on the surface. The question here is more specific. It is not about when to change, but about how to confirm that a rubber has reached the end of its working life and does not simply need a clean or an adjustment of expectations. The difference matters, because replacing a dirty rubber is an unnecessary expense, and playing on with a dead one is a handicap the player compensates for without realising.

The first step in any diagnosis is to rule out dirt. As explained in 13.5, a film of grease and dust reduces grip reversibly. Before declaring a rubber dead, it has to be cleaned thoroughly with the right product, left to dry, and assessed again. If the grip improves after cleaning, the problem was not the rubber but the maintenance. If it does not improve, what remains is real degradation.

Once dirt is ruled out, three hand tests help orient the diagnosis.

• The slide test. A ball is rested on the clean rubber and the bat tilted slowly. On a healthy rubber the ball holds to steep angles before slipping. On a spent one it slips with little tilt. The test is most expressive on inverted tensor rubbers; on tacky Chinese rubbers the reference is whether the ball stays put when the bat is turned fully upside down. If it no longer stays, the topsheet has lost the plasticisers that 4.6 described as irreplaceable.
• The bounce test. The ball is dropped onto the rubber from a fixed height — a hand's span is enough — and the rebound observed. A fresh sponge returns the ball with liveliness; a fatigued one damps more than expected. It is not a laboratory measurement, but comparison with a new rubber of the same model reveals differences the ear confirms: the impact sounds drier, less percussive.
• The visual test. The topsheet is examined under raking light. Areas of mechanical wear show up as shiny or smooth patches where the original microtexture has disappeared. On inverted rubbers those areas coincide with the usual point of impact — slightly off-centre towards the head and the dominant side — and are more extensive the more aggressive the playing style. Fine cracks, stiff rubber that does not recover its shape when pressed with the thumb, or edges of the topsheet separating from the sponge are signs of advanced degradation that leave no room for doubt.

Each type of rubber ages with an accent of its own. European and Japanese tensors lose the liveliness of the sponge first — the mechanical fatigue described in 4.6 — and the surface grip afterwards. Chinese rubbers with a tacky topsheet lose surface grip sooner, because their performance depends more on plasticisers that migrate and evaporate. Pimpled rubbers — short and long, covered in 6.2 and 6.3 — show wear differently: the cylinders deform, lose stiffness and stop reversing or cancelling spin with their original efficiency. A long pimple whose columns bend without recovering when pressed with a finger has exhausted its elastic capacity.

One phenomenon is worth naming: unnoticed adaptation. Wear does not happen overnight, and the player gradually adjusts the strokes — more force, more angle, more wrist — to compensate for what the rubber no longer gives. The result is that the loss of performance stays hidden until a new rubber goes on and the contrast makes plain how far the old one had deteriorated. If changing rubber brings back sensations the player thought were lost, the old one had been asking to be replaced for some time.

The diagnosis requires no instruments and no exceptional experience. An honest clean, the three hand tests and the occasional comparison with a fresh rubber of the same model are enough to tell whether the fault lies with the equipment or with the maintenance. When the tests confirm what the game suggests, prolonging the use serves no practical purpose: the rubber has given what it had, and the player deserves a surface that answers to what the arm puts in.