OK guys, Just like the other guy said, light and zero's cleat is almost identical and I have tesed and it works fine on both.Reviving an old thread just so the information is all in one place
The other difference is the 'C' shape metal piece is made of softer metal and open a little wider. However, the metal 'C' piece zero has same shape as light.
This make the metal easier to 'open' and clip on.
As for the pedal side, there is some slight difference in the opening being the light is earier to clip in...but it don't make much difference.
(cleat work on both).
Since I am a former long-time Zero user I had lots of old spare cleat parts around. But I just got a pair of Light Actions.
I compared the C-springs carefully with calipers. Thaey are absolutely identical. Same width, thickness, shape, angles, etc. They even have the same little star marks stamped on them (I don't know what the star means).
And I seriously doubt they are of softer metal, since all steels have virtually the same modulus of elasticity (stiffness).
I don't have an old Zero pedal to compare, but I suspect he difference must be in the little notch-shaped metal pieces under the bow tie. Those have the "bumps" that spread the C-springs to allow release. The Light actions are definitely easier to unclip, so it must be less dramatic an angle or smaller "bumps" on those pieces.
There is no difference to the security of the setup when you are clipped in. It is still completely impossible to pull out. But the Zeros had a definite unclip force when you moved your heel out to the release point. The LAs have a very small force as you rotate the heal out beyond the release point. The float of the LA's is a little more "ice-like" also, because the surface of the pedal has more surface area, and doesn't have the same cutouts as on the Zeroes.