PUSH RockShox FAQ
How does the PUSH Factory Tuning improve the harsh feel during high-speed repetitive bumps?
On standard forks, if you have the rebound speed nice and slow for the first 50mm of travel, it will be too slow when you go deep into the travel, and the fork can’t return quickly enough. The PUSH Factory Tuning system has a high-speed shim stack which allows the fork to return quicker deep in the stroke, giving a much better response and feeling of more travel.