Has anyone ever done a comparison between the old and new style of HW seal?
The previous type had a much thinner and more flexible sealing lip than the current ones, at least the 26 and 30mm versions.
My hypothesis is that the earlier flexible lip seal should give higher friction at high pressures, and thereby slow piston bounce.
Someone on here made up a test rig (BTDT?) that was able to measure action movement and therebay document piston bounce/slap/surge.
Swapping between the two styles of HW seal and doing this measurement would be a very interesting topic for a basement mechanic like me.