Zeb always harsh and can’t get setup right

[weiran]

I have a 2021 Zeb Select that came with my Vitus E-Sommet VRS that I just can't get setup right, it's always harsh even with too little or too much pressure, and I'm now wondering if I have a faulty fork.

The main issue seems to be a relatively strong force sucking it into it's travel. This means with no load on the forks (bike is lifted up), it sits at about 10% sag even with plenty of pressure in the shock (60psi+). The fork feels incredible stiff and takes out almost none of the low level chatter on trails. Probably the opposite of plush, you really have to ride it hard before the fork begins to come alive.

My internet research suggests this is a problem with the negative air chamber being unbalanced, and I've tried various tips to equalise pressure without success: zip tie in stanchion gap while fork is at 30% sag, pumping from 0psi in 10psi steps and cycling the fork every time.

Any other suggestions of what I can do, or do I have a faulty fork I need to get replaced or is this just expected for the budget Zebs?

 

[irie]

This thread might help.

Zeb ultimate 2023 170mm harsh ride

I just upgraded my forks at the weekend to 2023 Zeb Ultimate 170mm I used the trailhead app to get my recommened psi (120kg -99psi) Worh refund on -6 as recommended also by the app and hs and ls compression open , the ride was harsh, really hard and unfor giving . After reading on some us...

www.emtbforums.com

 

[Rod B.]

I have a 2021 Zeb Select that came with my Vitus E-Sommet VRS that I just can't get setup right, it's always harsh even with too little or too much pressure, and I'm now wondering if I have a faulty fork.

The main issue seems to be a relatively strong force sucking it into it's travel. This means with no load on the forks (bike is lifted up), it sits at about 10% sag even with plenty of pressure in the shock (60psi+). The fork feels incredible stiff and takes out almost none of the low level chatter on trails. Probably the opposite of plush, you really have to ride it hard before the fork begins to come alive.

My internet research suggests this is a problem with the negative air chamber being unbalanced, and I've tried various tips to equalise pressure without success: zip tie in stanchion gap while fork is at 30% sag, pumping from 0psi in 10psi steps and cycling the fork every time.

Any other suggestions of what I can do, or do I have a faulty fork I need to get replaced or is this just expected for the budget Zebs?

Weiran,

Here are some some suggestions for you:

Did you buy your E-Sommet VRS new? I mention this because if you bought the bike used, it's possible a previous owner may have installed additional air volume spacers on the fork's air spring side. This will alter the fork's spring rate and can cause the fork to ride stiff. You may want to pop the air cap off and see how many volume spacers are installed. I would suggest starting off with zero air volume spacers and see how your fork feels. If you find the fork is bottoming out on your rides despite having set correct sag, i.e. 30%, then add a volume spacer.

I would not pay particular attention to Rockshox's suggested starting air pressures. It's been my experience that they are way too high. With your ride gear on, set your ZEB to correct sag, i.e. 20-30% using whatever air pressure works for you and not what Rockshox suggests.

If the fork is used and you don't know it's history, or you've put a few hours on your fork since it was new, you may want to perform a 50 hour fork service on your ZEB. The 50 hour service involves removing the lower fork assembly and re-lubing the foam wiper seal rings. The foam wiper seals on your ZEB will eventually become caked with dirt and dry out. When this occurs, your ZEB will lose small bump compliance and it will ride harsh and stiff. Occasionally you want to turn your bike upside down and let it sit for about 30 minutes. This will allow the oil in the lower fork tube to rehydrate the foam wiper seals. Performing a 50 hour service will greatly improve small bump compliance and make your fork feel nice and plush.


Whenever I have a situation where my fork feels like it's imbalanced, i.e. "Suck Down", I will let all of the air out of my fork and cycle it a few times. I will then add two to three BAR and cycle the fork up and down about ten times. When you do this, it will even out the pressure in your fork as you add air. You do not want to add air to your ZEB all at once, this will cause an imbalance in the fork. Add air in small increments as you cycle the fork. Do this until you reach correct pressure.

Occasionally, things can go wrong with your ZEB, i.e. an "O" ring on the air spring piston is cut or goes bad from lack of lubrication, etc. When this happens, it will cause suck down. Here's a GMBN video which describes suck down and how to fix it. Before you disassemble your fork, try letting all the air out of the fork and then gradually add air while cycling the fork up and down.


Lastly, here's a great article on volume spacers and air spring curve rate.

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[Tooks]

I’ve found over the years that sending troublesome under performing forks to a reputable service centre is the most cost effective way to go.

They’ll ask for the bike details/weight/riding style etc, and it should come set up nicely.

I’ve used TF Tuned in the past, and JTech, and both times the fork or shock came back performing like new, or sometimes better than.

If you do fancy a go yourself first, the links and advice that @Rod B. Has posted is great.

 

[weiran]

Thanks all for your advice.

I tried the various tips like taking some air out the fork and pulling it up and down, and they helped but didn't fully fix it.

I ended up doing a lower leg service which solved the problem - basically did the same as that GMBN video Rod posted. There was a huge blob of grease around the top of the air spring which I assume was blocking the bleed port. I cleaned it up, regreased and oiled and now it works perfectly.

As a bonus I can now do lower leg services myself!

 

[Bndit]

Everyone who has problems with forks should start with the service, even if the fork is new. Just got my Fox 36 back from first service and it had also lots of grease blocking air flow…from the factory Same thing with new brakes, if there`s any problems, bleed them, evan as new