I have Klematch P37, high quality rails with a standard profile (shown in the video).
View attachment 906510
The DIN53512 standard is harmonized with
ASTM D1054 and uses a standard sample to measure rebound with a precision pendulum machine
like this one. I can estimate the immediate rebound by multiplying my measurements by 7/5. So the immediate rebound of my rails are:
47°F: 51.7 x 7/5 =
72.5%
80°F 54.8 x 7/5 =
76.7%
These are both within the manufacturer's spec, and as expected, I get more rebound when the rubber is warmer.
What I've shown is that the DigiBall is capable of making accurate rail rebound measurements.