New Zeb 2023 doesn't stay at full extension

[torabora851]

Hi, I've just installed the 170mm Zeb, and found that it doesn't stay in a fully extended position (like the previous Zeb, or Lyrik I have). Under the bike weight, just staying on the ground the measurement is 160mm, when I lift the bike up, under the wheel weight it shows 165. Only if I forcefully push the wheel out, it reaches 170mm, but it doesn't stay in that position and returns back to 165mm. So basically 170mm Zeb stays on the same level as Fox Rythm 160mm it replaced.

Is it normal for the debon air+ or should I send the fork back under warranty?

 

[Dax]

Has it got the air relief valves on the legs? If so let the air out, otherwise check out YouTube on burping forks with a cable tie

 

[irie]

The ZEB A2 has air release valves on the legs.

 

[Cb750stu]

So is it sucking up the fork without weight on the front ??

 

[steve_sordy]

Did you inflate the fork in stages, compressing the fork half a dozen times between each step? How to do it should be in the manual. Also on YouTube.

 

[torabora851]

Did you inflate the fork in stages, compressing the fork half a dozen times between each step? How to do it should be in the manual. Also on YouTube.

Yep, I can hear the sound of equalization.

So is it sucking up the fork without weight on the front ??

Yep, around 10mm.


Actually, after a day of riding rough trails today (it was the first ride after I installed it) it stays almost fully extended. So probably it was not equalized lower legs (but I pressed release valves! no hissing sound). Thanks all for the help

 

[head]

I had a similar issue with Fox 38. I equalized everything a few times, but it did not help. Then I rode it a few times, and it worked as expected!

From what I read on forums, there could be too much grease from the factory that blocks something. I don't know, I'm not a suspension nerd. However, riding the fork helped .

 

[irie]

I had a similar issue with Fox 38. I equalized everything a few times, but it did not help. Then I rode it a few times, and it worked as expected!

From what I read on forums, there could be too much grease from the factory that blocks something. I don't know, I'm not a suspension nerd. However, riding the fork helped .

My Zeb A2 works fine for now, but wouldn't be surprised if the first time I do the lower leg service I'll find too much grease ...

Edit 25 Oct 2023: did find too much grease when did lower leg service ...

 

[Stoneilove]

I had a similar issue with Fox 38. I equalized everything a few times, but it did not help. Then I rode it a few times, and it worked as expected!

From what I read on forums, there could be too much grease from the factory that blocks something. I don't know, I'm not a suspension nerd. However, riding the fork helped .

I had the same thing with my 38, after the first ride it was fine.

 

[EnduroDad2k]

If these were motorcycle forks it would likely indicate a bad air seal. Hope it resolves itself!

 

[Bones]

Welcome to the world of mtb forks. If you are not heavy enough to have at least 100psi in the fork to get your sag right then it's going to drop under the weight of the bike. These forks are a generic setup. Even if it's got an emtb shim stack the air side is standard . So stick a motor and a 4.5kilo battery into the equation and something has to give. Just my way of thinking about it having the same issue with fox 38's.

 

[torabora851]

I found a previous DebonAir, and compared it with the new DebonAir+. Interesting that the air piston ring on the new DebonAir+ is located lower by 10mm than the previous one. Taking that the equalizing dimple is located exactly on the level of the previous air spring piston the new piston is ~10mm lower than the equalizing point. That means that on the maximum extension, the negative spring has higher pressure than the positive and this explains why the fork sits lower than the maximum travel.

 

[toniobr]

Hi, I've just installed the 170mm Zeb, and found that it doesn't stay in a fully extended position (like the previous Zeb, or Lyrik I have). Under the bike weight, just staying on the ground the measurement is 160mm, when I lift the bike up, under the wheel weight it shows 165. Only if I forcefully push the wheel out, it reaches 170mm, but it doesn't stay in that position and returns back to 165mm. So basically 170mm Zeb stays on the same level as Fox Rythm 160mm it replaced.

Is it normal for the debon air+ or should I send the fork back under warranty?

I have the same problem.
I compared my ebike with Zeb A2 with my friend's ebike with Zeb A1 and my fork is more inside. The other day my bike was on a pikup along with other bikes with the wheel out and all the other 170 Fox bikes were visually longer than my zeb 170.

 

[parkp81]

I had the same issue after I completed a lower leg service and came across the following possible solution which resolved the issue.

Remove pressure from the fork.

Cycle the fork every 10 psi down to equalize the chambers. Pressed release valves after cycling.

When it was at 0psi I pressed the release valves on the back of the lowers while pressing down the fork to max travel until I could hear no more air being released.

Then inverted the process on the way back up.

 

[toniobr]

I had the same issue after I completed a lower leg service and came across the following possible solution which resolved the issue.

Remove pressure from the fork.

Cycle the fork every 10 psi down to equalize the chambers. Pressed release valves after cycling.

When it was at 0psi I pressed the release valves on the back of the lowers while pressing down the fork to max travel until I could hear no more air being released.

Then inverted the process on the way back up.

is your Zeb fork the 2023?
Anyway the equalization should be automatic when we move the fork up and down, only if there should be more pressure in the negative chamber than the positive one you need to lock the wheel and pull from the handlebars.
After a service there may be grease clogging the equalization channel so the fork has problems balancing itself however this is not my case.
I think our problem is as torabora851 said.

 

[parkp81]

is your Zeb fork the 2023?
Anyway the equalization should be automatic when we move the fork up and down, only if there should be more pressure in the negative chamber than the positive one you need to lock the wheel and pull from the handlebars.
After a service there may be grease clogging the equalization channel so the fork has problems balancing itself however this is not my case.
I think our problem is as torabora851 said.

Mine is the 2023 Zeb Ultimate 170mm on my non ebike that I had an issue with and corrected. Zeb Select on my Giant Reign E+ ebike is showing correct travel as well. Additionally when it was having an issue now showing full travel, I did notice the fork was very stiff, even with lowering the psi, now that is no longer an issue. It's worth a shot to give what I did above a try as it worked for me and others.

 

[toniobr]

I found a previous DebonAir, and compared it with the new DebonAir+. Interesting that the air piston ring on the new DebonAir+ is located lower by 10mm than the previous one. Taking that the equalizing dimple is located exactly on the level of the previous air spring piston the new piston is ~10mm lower than the equalizing point. That means that on the maximum extension, the negative spring has higher pressure than the positive and this explains why the fork sits lower than the maximum travel.

View attachment 110191

I think you are right and if the probla does not occur at all it is because Rochshox later may have moved the balance hole and the problem is only on the first 2023 forks. My fork is from September 2022.
Have you written to Rochshox infernational for clarification?
Thank you and have a nice day
Tonio