New vs. Old Golf Ball: When should you switch golf balls?
With this test we want to find out how worn out a ball can be before it is unplayable. For this purpose we take a worn out Titleist ProV1 X that can no longer be used for fittings. The wear happens relatively quickly in our fittings, as the ball hits a curtain at full speed and is slowed down there. As we can see, this ball is actually completely worn out and the print is barely visible on the cover. Usually our balls burst at some point if they are not changed in time and this ball looks like it is about to burst very soon.
When we hold such a ball in our hands at the tee, we immediately head for the rubbish bin. But the question is whether this is really justified and whether the ball is possibly still playable.
It is time to find out and so we hit a number of balls alternately with a 6 iron, taking great care to have a sample that is large enough and that the strike pattern is consistent. We are particularly interested in the spin and therefore pay close attention to the dynamic loft.
Our result is as follows:
The differences are marginal. The club head speed was minimally higher with the new ball and the dynamic loft 0.5° flatter. The launch angle was also 0.5° flatter.
What interests us most is the backspin because it is to be expected that this is unplayably low with the old ball. However, the difference is only 43rpm. Now we have to take into account that the dynamic loft with the old ball was 0.5° higher and therefore about 60-70 rpm more spin would be the result. If we add this up, we get a result of about 100rpm difference in spin. At 5300rpm this is certainly not much.
Also interesting is the fact that the difference in launch is exactly the same as the difference in dynamic loft. What doesn't seem to happen is that the old ball develops less grip on the clubface and slides "across the clubface" - as in a wet clubhead.
What you also can't necessarily say is that the standard deviation of the results is higher with the old ball. Here one would think that the fluctuations are greater because the used ball reacts differently depending on where it was struck. However, this is only partly the case. In terms of launch and spin, the deviation is even lower than with the new ball. Only in ball speed and carry length the variance is higher with the old ball. However, it is difficult to draw conclusions from this because this trend is not statistically significant.
Our conclusion: Does a worn ball become unplayable?
Definitely not - at least not if the ball is worn out like ours and the core is still intact. Only a worn out cover doesn't seem to make much difference - to everyone's astonishment. A spin difference of a good 100rpm with a 6 iron and 1m less length is really not that meaningful. Even good amateur players should have no difficulties with this.
What we have not tested here, of course, is the behaviour around the green when even small differences in spin play a role. And we must not overlook the fact that our test ball was worn very evenly. There are also balls that have a cut in certain spots and therefore may not fly as they should.