Suspension Component Technology/Functionality Discussion

1 day ago
iceman2058 wrote:
Introducing the ZETA Damping Cartridge by SIMONS.LABExternally adjustable compression and rebound tunes, Hydraulic Bottom-Out packaged in a drop-in cartridge design: ZETA is now available for...

Introducing the ZETA Damping Cartridge by SIMONS.LAB

Externally adjustable compression and rebound tunes, Hydraulic Bottom-Out packaged in a drop-in cartridge design: ZETA is now available for FOX 38, RockShox ZEB and Intend upside-down suspension forks.

Many riders know the situation: changes to the compression or rebound damping do not produce the desired effect on the trail, or an improvement in one area comes with noticeable compromises elsewhere. This is often caused by the predefined internal base tune found in conventional suspension forks. External adjusters can fine-tune this base tune, but they cannot fundamentally change it. If the tune does not match the spring rate, rider or desired ride feel, the available adjustment range can quickly reach its limits.

ZETA assembly 1.jpg?VersionId=MEZY4IDi2Grp0vMhZq CFl

This is where the ZETA damping cartridge comes in. Its HSC and HSR Tune Adjusters change the base compression and rebound tunes externally - comparable to modifying the internal shim stack, but without having to open the cartridge. ZETA is the first product from SIMONS.LAB, a young suspension start-up based in Freiburg, Germany. The technical foundations of the damping concept were developed as part of Simon Reiberg’s Master’s thesis. Building on this research, more than two years of development, several prototypes, numerous dynamometer tests and extensive testing on the trails have resulted in the now production-ready ZETA damping cartridge.

ZETA riding 1

ZETA IN DETAIL

The compression unit uses a non-preloaded tapered shim stack. This creates a predominantly linear to slightly digressive damping characteristic. As shaft speed increases, damping force builds consistently and predictably, without sudden changes in the force curve. The HSC Tune Adjuster provides seven different base tunes. This allows the overall level of compression damping to be matched to rider strength, personal comfort preferences and trail characteristics. A separate Low-Speed Compression adjuster with 23 clicks then provides the fine adjustment.

SL ZETA HSC Sweep

Seven base tunes are also available on the rebound side. The HSR Tune Adjuster allows the damping to be matched to the spring rate, which is influenced by factors including rider and bike weight as well as the chosen spring setup. At the same time, it changes the overall character of the fork: depending on personal preference, the fork can be set up to feel calmer and more planted or faster and more lively. The Low-Speed Rebound adjuster offers 20 clicks for fine-tuning within the selected base tune.

SL ZETA HSR Sweep.png?VersionId=Va5axzEq

A position-sensitive Hydraulic Bottom-Out system becomes active during the final 25 millimeters of travel. It increases damping force shortly before the end of the stroke, providing additional control during deep compressions and hard landings before the fork reaches a mechanical bottom-out. This allows the regular compression tune to remain more supple throughout the rest of the travel while providing additional reserves near the end of the stroke. Bottom-out resistance therefore does not have to be generated solely through a highly progressive air spring setup.

SL ZETA HBO cycle

The hydraulic foundation of the cartridge is a dual-tube architecture. Displaced oil is directed through separate compression and rebound circuits and partially returned through the space between the inner and outer tubes. A spring-loaded IFP compensates for the oil volume displaced by the damper shaft and keeps the closed cartridge pressurized. This layout makes it possible to combine the two Tune Adjusters, the conventional low-speed adjusters and the Hydraulic Bottom-Out system within a single cartridge.

ZETA Cartridge Detail 2
ZETA Compression unit.jpg?VersionId=mswnqvNp

Despite the wide adjustment range and number of available settings, riders do not have to start from scratch. For every order, SIMONS.LAB provides a recommended starting setup based on rider and bike weight, fork model, travel, intended use and personal preferences. From this baseline, the setup can be adjusted towards greater comfort, more support or a calmer or more lively ride feel.

ZETA riding 6

“Not every rider is looking for the same ride feel. Ultimately, ZETA is not intended to dictate how a fork should feel,” says Simon Reiberg. “The cartridge provides the adjustment range needed to find what actually works for the individual rider and their riding style.”

FACTS AND FIGURES

Adjustability

  1. Low-Speed Compression: 23 clicks
  2. High-Speed Compression Tune Adjuster: 7 tunes
  3. Low-Speed Rebound: 20 clicks
  4. High-Speed Rebound Tune Adjuster: 7 tunes

Features and Architecture

  • Hydraulic Bottom-Out system during the final 25 mm of travel
  • Dual-tube architecture
  • Closed cartridge with a spring-loaded IFP (Internal Floating Piston)
  • Weight: from 390 g

Compatibility

  • FOX 38 (model years 2021–2026)
  • RockShox ZEB (model years 2021–2027)
  • Intend upside-down forks with 35 mm stanchions (excl. Samurai models)
  • Further applications are planned.

Installation

Depending on the fork platform, the ZETA damping cartridge can be installed by the customer. Installation instructions are available online. Alternatively, SIMONS.LAB offers a Factory Installation service for customers within the European Union. The cartridge is installed as part of a lower-leg service, and the complete fork is then returned ready to install on the bike.

Pricing and Availability

The ZETA damping cartridge is now available directly through SIMONS.LAB. Prices start at €486,55 excluding VAT (€579 including German VAT).

TEAMROBOT wrote:
This is a lot of cool stuff packed into one aftermarket damper, and if it works as advertised that would be unreal for puzzlers and tweekers...

This is a lot of cool stuff packed into one aftermarket damper, and if it works as advertised that would be unreal for puzzlers and tweekers like me. I'm really curious to learn more about how the "tune adjuster" works, because I too don't understand what it means when they say the "tune Adjuster provides seven different base tunes."

Obviously we're not changing shim stacks with the turn of a knob, so I'm curious what they mean when they're refering to a base tune vs. an adjustment. 

If it works like they claim they’ll be beating Vorsprung to the punch in fork dampers. Steve stated in the latest podcast with Remy that the fork damper they’re working on is aiming to have similar tune-ability as the Telum. 

4
johnsogr
Posts
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Location
Toronto, ON, CA
1 day ago

Will be really cool to see what Steve comes up with - I implored him to make sure the damper first in an inverted chassis!

2
1 day ago Edited Date/Time 1 day ago
johnsogr wrote:

I wonder if it's adjusting the clamp shim diameter similar to the Vorsprung Telum?

Slavid666 wrote:
Which is what ohlins has been doing since their entrance into the MTB market. From the assembly video it looks like the HSC adjustment is somewhat unique...

Which is what ohlins has been doing since their entrance into the MTB market. 

From the assembly video it looks like the HSC adjustment is somewhat unique. From what I can tell the piston has 3 main ports with a number of smaller ports, on the same BCD, that can be blocked from the flow path decreasing the amount of port surface area of the face shim, very different than the ellipse camp plate on the ohlins HSC circuit which adjusts the clamp diameter and the resulting force curve slope. No idea if it rides the same but I would be interested to get my hands on one for an extra zeb chassis I have lying around. TBH I would really like to try one in a Dh fork over a enduro fork... Will have to email to see if that is ever going to be a possibility. 

Its cool to see where this has come since eurobike last year! Really stoked that it came to market!

TEAMROBOT wrote:
Could you share a little bit more info about how Ohlins does their ellipse clamp plate for HSC? And is that tech included in Ohlins forks...

Could you share a little bit more info about how Ohlins does their ellipse clamp plate for HSC? And is that tech included in Ohlins forks, shocks, or both?

I'm curious how it compares to the Vorsprung Rapid ReValve adjustment. Sounds like it's pretty similar.

Telum Tuning with Rapid Revalve: We're extremely excited to be able to open  up our entire CUSTOM TUNING process to the world! Rapid Revalve and the  Vorsprung Tuning Hub put power in

Vorsprung sorta answered that question underneath the Instagram post your image comes from.

image 777
 

2
Slavid666
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168
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Location
Santa Rosa, CA, USA
1 day ago
johnsogr wrote:

I wonder if it's adjusting the clamp shim diameter similar to the Vorsprung Telum?

Slavid666 wrote:
Which is what ohlins has been doing since their entrance into the MTB market. From the assembly video it looks like the HSC adjustment is somewhat unique...

Which is what ohlins has been doing since their entrance into the MTB market. 

From the assembly video it looks like the HSC adjustment is somewhat unique. From what I can tell the piston has 3 main ports with a number of smaller ports, on the same BCD, that can be blocked from the flow path decreasing the amount of port surface area of the face shim, very different than the ellipse camp plate on the ohlins HSC circuit which adjusts the clamp diameter and the resulting force curve slope. No idea if it rides the same but I would be interested to get my hands on one for an extra zeb chassis I have lying around. TBH I would really like to try one in a Dh fork over a enduro fork... Will have to email to see if that is ever going to be a possibility. 

Its cool to see where this has come since eurobike last year! Really stoked that it came to market!

TEAMROBOT wrote:
Could you share a little bit more info about how Ohlins does their ellipse clamp plate for HSC? And is that tech included in Ohlins forks...

Could you share a little bit more info about how Ohlins does their ellipse clamp plate for HSC? And is that tech included in Ohlins forks, shocks, or both?

I'm curious how it compares to the Vorsprung Rapid ReValve adjustment. Sounds like it's pretty similar.

Telum Tuning with Rapid Revalve: We're extremely excited to be able to open  up our entire CUSTOM TUNING process to the world! Rapid Revalve and the  Vorsprung Tuning Hub put power in

Screenshot 2026-08-11 142936 0.png?VersionId=Q7uPca4gTDbE6uVe.ToIdtNAye
P1
Screenshot 2026-08-11 143004 0
P2
Screenshot 2026-08-11 143211 0.png?VersionId=QATqOcwqZm5JbWr
P3
3
Slavid666
Posts
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Location
Santa Rosa, CA, USA
1 day ago Edited Date/Time 1 day ago

My statement about it being an ellipse is somewhat misleading; it's more of a stepped clamp that mimics changing the clamp shim in that it alters the slope of the force vs velocity damping curve. Hope the pictures help explain what I am describing. 

*EDIT: Yes, this is used in both forks and shocks for HSC adjustment. 

 

3
TEAMROBOT
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Los Angeles, CA, USA
Fantasy
1 day ago
Slavid666 wrote:
My statement about it being an ellipse is somewhat misleading; it's more of a stepped clamp that mimics changing the clamp shim in that it alters...

My statement about it being an ellipse is somewhat misleading; it's more of a stepped clamp that mimics changing the clamp shim in that it alters the slope of the force vs velocity damping curve. Hope the pictures help explain what I am describing. 

*EDIT: Yes, this is used in both forks and shocks for HSC adjustment. 

 

Thanks @Slavid666 and @FrontRangeFriend for the info. That helps!

2
5 hours ago

Want to learn a whole lot about suspension stuff from the guy that designed the Sixfinity for the Yeti LT?

https://youtu.be/URjie8hlZyw?si=_gu7uQ2DmkjfDqZt

 

I have a fairly solid understanding of suspension kinematics and some of this discussion made my head spin lmao

2
johnsogr
Posts
41
Joined
3/31/2013
Location
Toronto, ON, CA
2 hours ago

Just put money down for a Simons.lab damper for my Intend Edge, can't wait, will report back.

2

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