Rod B.
Well-known member
Mcharza,Thanks for really good info.
Also, at least my Zeb Ultimate 2023 does the following.
When I slowly let the air out, it sucks itself in. After that, you have to forcefully pull it to its full length, letting the air out of the negative side.
I do this from time to time and sometimes it's really tight.
After this, when you add air to the desired pressure, the fork works sensitively again.
There are a number of reasons for "Fork Suck Down." I've experienced the issue on several occasions. If the factory over greases the air spring piston it can cause a suck down issue due to too much grease.
Every air chamber/air spring fork, has a "Negative" and "Positive" side to the air chamber/air spring. The two chambers must be balanced. Most of the time, when I've encountered suck down, its because I was in a hurry after reassembling a fork and did not adequately cycle the fork up and down to balance out the two air chambers as I pumped the fork back up. If you have air bleed ports on your fork, they will help with balancing the air chambers.
There are other issues that can also cause chronic fork suck down, this includes a bad O Ring on the air spring shaft or air piston, etc. Instead of writing a novel, here's a good video on "Fork Suck Down."
Be safe,
Rod