Technicals

Introduction: Aeron Types

With almost 30 years of production run, the Aeron Chair has received many updated changes and transformations over the years, some external and various others are internal.

 

In a layman’s view, the 2 main versions of the Aeron are the Aeron Classic (1994 till 2016) and Aeron Remastered (2017 till Current).

 

While the 2 versions may look similar at first glance, they are in fact very different chairs, with how they recline, how the mesh feel, how the functions work, and especially the ergonomics of their back support.

 

In a more detailed view, even the Aeron Classic comes in different generations with various updates externally and internally. Most casual buyers and even some veteran pre-owned sellers are unaware of these differences, or otherwise, those who are aware may try to conceal, or even mislead unsuspecting buyers. With over 3 decades of accumulated experience in the office ergonomics and office planning industry, this write up by us at Ergo Supplies Pte. Ltd. will serve as a guide for you to identify the value of the chair that you are purchasing, and prevent yourself from getting misinformed by dishonest sellers.

 

Identifying: Classic vs Remastered

 

The fool-proof method of identifying a Classic and Remastered Aeron would be from the mechanism. The mechanism of the Aeron Classic comes in a Barrel Shaped Casing, with control Pedals on the right side of the seat pan. Whereas the Aeron Remastered mechanism comes in a Flat Shaped Casing, with control Knobs on the left side of the mechanism.

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Identifying: Classic 1st / 2nd / 3rd Generation

Now that you have identified the Classic from the Remastered, and if you have concluded that you are looking at the Aeron Classic, we can proceed to identify the generation of the Aeron Classic that you are looking at.

 

When purchasing a pre-owned Aeron, it is important to identify the age of the chair in order to make a fair valuation of the price you should be paying for. Similar to the pre-owned car market, the pre-owned chair market is equally filled with unscrupulous resellers/scalpers/traders who would use crafty techniques to misrepresent what they are selling, mislead, or trick unsuspecting buyers. In most cases, misrepresenting the age and condition of the chair, replacing faulty original parts with after-market parts, combining parts from different chairs, or hiding faults of the chair. The age of the chair represents the amount of wear and tear on the mesh and mechanism, as well as the replaceability of parts. While the mechanism case may look identical on the exterior, internal parts are not universally compatible between the different generations. Few examples of such differences would be the tilt sector gear, tilt limiter stopper, tilt cable, pneumatic cylinder, and pneumatic cylinder actuator.

 

The age of the chair also represents the costs and serviceability of the chair. The older the generation of the chair, the scarcer are the parts, whereas the newer the chair, the more expensive it is to get the parts. It will be at your own discretion to weigh the cost-benefits.

 

Changes and updates are made over the years, some of which may overlap between the period, hence there is not an officially established cut off timeline that can be drawn to segregate the generations. For simplicity of referencing, we will use the following years to categorise them into 3 different generations:

 

1st Generation Classic (1G): 1994 – 2004

2nd Generation Classic (2G): 2005 – 2012

3rd Generation Classic (3G): 2013 – 2016

 

The next important factor to look at, is the configuration of the chair. Because the Aeron comes in a multitude of combination in adjustability features and materials, as such, the price you should be paying will highly depend on what features the chair is configured with.

At the same time, the features also serve as a guide on areas too look out for, to identify the generation of your chair.

 

Below is the list of default features and add-ons:

 

Default Adjustments

Chair Height (1st Gen vs 2nd Gen vs 3rd Gen Pneumatic Cylinder)

Recline Tension

 

Add-on Adjustments

[Sliding Lumbar Support] or [Adjustable PostureFit Sacral Support]

Adjustable Armrests (Knob Style vs Lever Style)

Tilt Limiter (1st Gen vs 2nd Gen vs 3rd Gen Sector Gear)

Forward Tilt

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1st Generation Aeron Classic

Assuming that all parts are original and they have not been swapped, a simple method to identify a 1G Aeron is by looking at the Adjustable Armrests (if applicable). The 1G Aeron uses a knob style adjustment, where height adjustments are made by loosening the knob on each arm, lifting/lowering arms to the preferred height, and tightening the knob to lock them in place. However, if the Aeron that you are looking at does not come with Adjustable Armrests, you can proceed with the next option, which is to look at the pneumatic height cylinder. The 1G Aeron uses a 2 stage height cylinder, with a plastic bushing cap on the first (lower) stage cylinder.

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However, if the Aeron that you are looking at does not come with Adjustable Armrests, you can proceed with the next option, which is to look at the pneumatic height cylinder. The 1G Aeron uses a 2 stage height cylinder, with a plastic bushing cap on the first (lower) stage cylinder. The 2G and 3G Aeron both uses a single stage cylinder with a narrow cut out on the top. While the 2G and 3G Aeron's cylinder may look identical externally, they are entirely different in terms of their cylinder actuating mechanism.

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This 1G cylinder is also known to have wobble issues.

 

To test for wobble:

  1. Raise the chair to the maximum height

  2. Stand behind the chair and hold the top of the chair’s back

  3. Slightly wiggle the chair forward/backwards, and sideways

If the chair is wobbling tremendously, the cylinder requires replacement.

One other important difference in their internal parts that differ from the generations would be the tilt sector gear and cable mechanism. This mechanism being one of the most common faults in the Aeron Classic has been revised over the years to prevent breakage in the rotating stem, and improve on the secure of the cable. To view this however, will require the removal of the tilt case. An honest and sincere seller will be more than happy to open the casing for your viewing before purchase. Below are the different generations of the sector gear, and cable mounting types.

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2nd & 3rd Generation Aeron Classic

The 2G Aeron and 3G Aeron are tougher to differentiate from each other, as they both uses the same Lever Style Adjustable Armrests and similar looking height cylinder. However, a few differences would be in the material of their arm pads and the style of their height cylinder actuation mechanism.

 

The 2G Aeron uses a firmer plastic-like vinyl arm pads, whereas the 3G Aeron in the later years uses a softer and more pliable polyurethane foam arm pads. This can be differentiated by pressing on the pads with your thumb, or removing the arm pads to look at the underside. From the underside, the vinyl arm pads can be differentiated if you are able to see that the material is wrapped as a separate outer layer. The polyurethane foam arm pads on the other hand is a one piece foam without an external wrapped layer.

An alternative more intrusive but more accurate option would be to open up the tilt covers and look at the upper side of the mechanism. The 2G and 3G Aeron chairs uses completely different pneumatic cylinder actuation mechanisms, and these cylinders are not interchangeable.

 

The 2G Aeron uses a top actuated cylinder where a set screw compresses downwards to make the activation and release air into the piston.

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The 3G Aeron however uses a side actuated cylinder, whereby a cable system pulls a lever sideways to make the activation, which requires no set screw adjustments.

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Another less intrusive alternative would be to look at the bottom tilt cover, however this option provides a less definite assurance as the transition was made towards the end of the 2G Aeron, you will therefore be able to find 2G Aeron chairs with 2 different type of bottom covers. By looking underneath the base mechanism, you will be able to observe that the earlier 2G Aeron uses the same closed-style bottom tilt cover as the 1G Aeron, whereas the later 2G and 3G Aeron uses an open-style bottom tilt cover as per photo examples below.

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With the above information, you should now be able to not just identify the Aeron that you are purchasing, but at the same time assess the value you should be paying for a pre-owned unit. This write up by us at Ergo Supplies Pte. Ltd. is an effort to promote market transparency, especially in the pre-owned chair market, and to assist buyers where a brand new Aeron is beyond their budget.

Comparison: Classic vs Remastered

 

In the previous section, we have broken down the differences between the generations of the Aeron Classic, and how to identify the age and features of the chair. In this section we will be breaking down the differences between the Aeron Classic and Aeron Remastered, and make a detailed comparison for individuals who are deciding between a pre-owned Aeron Classic and a brand-new Aeron Remastered.

 

The Aeron Classic has held its general design and mechanism for almost 3 decades, and has organically evolved into a recognisable icon in some of the world’s largest financial and tech organisations, even in the Museum of Modern Art. With competition pulling along and expiring patents, the largest change and overhaul took place in 2016 when Herman Miller introduced the new generation Aeron, the Aeron Remastered. While keeping the same design language, and staying true to its original silhouette, the Aeron Remastered however is an entirely different chair from the Aeron Classic. These differences include the recline ergonomics, mechanism workings, weight balance, mesh form, back support, and the armrests ergonomics.

 

Recline Ergonomics – Kinemat Tilt

The Aeron chair famed for its unique Kinemat Tilt has held its top position in the seatings industry, and this still holds true till today. While the name remains unchanged, the mechanics were further improved through it transition into the Aeron Remastered. The entire overhaul of the base mechanism entirely changes the mechanics of how the chair reclines. The changes were made to allow better control of recline through the user’s body movement, hence reducing the need for adjustments through the tilt limiter and tilt tension. Herman Miller have managed to achieve this by shifting the recline pivot point from the front of the chair, to the center of gravity point below the user’s body weight.

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When seated on the Aeron Classic, the recline pivot point was designed to be at the front of the chair (i.e. Infront of user’s center of gravity), where the recline is activated by the downwards force of your body weight (i.e. sitting force). This also means that without locking the tilt limiter or tightening the tension knob, the chair will always be in recline as along as the user is seated. Users who switch between upright and recline seating positions will find themselves having to make changes to the adjustments very frequently. On the Aeron Remastered, the recline pivot has been shifted rearwards, close to the center of gravity of the user. This improvement created an extremely responsive recline, controlled simply through the user’s leaning movement and allowing for upright seating without frequent changes to the tilt settings nor constant adjustments of the tension knob.

Mechanism Workings & Tension Balance

Apart from the change in pivot position, the entire overhaul of mechanism takes place internally as well. Switching over from the traditional torsion spring and extension spring mechanisms, Herman Miller engineered the recline system to take advantage of a much more simplistic leaf spring mechanism. This change has made multi aspects enhancements, in durability, ease of service, cost of service, as well as the fluidity of recline.

 

Traditional torsion spring mechanisms provide torque through rotational movements and are prone to wear and tear. Good examples can be found from old samples of the Aeron Classic, whereby squeaks and creaks (on slow recline movements) are often heard from the main barrel which is sealed for safety and cannot be lubricated. These squeaks and creaks develop from wear and tear in the internal main spring, which causes friction and micro vibrations being amplified through the hollow plastic casing.

 

The switch to leaf springs similar to those used in vehicular suspension systems, reduces the number of moving parts, contact points, friction and therefore wear and tear in the entire mechanism. The minimalistic system also improves the ease and cost of parts replacement for the Aeron Remastered. This is done so through the improved modularity, where individual tension plates can be replaced, instead of the entire sealed barrel in that of the Aeron Classic. With the reduced number of moving parts, contact points and friction, recline fluidity is also greatly increased. 

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Another design drawback of the traditional torsion spring system is the tension imbalance on each side of the chair, caused by its asymmetrical layout. The usage of a single spring for both the rear recline and forward tilt mechanism only allows for a one sided support on the swing arm (yoke), for each rotational direction. Rearward rotation is supported by the left swing arm, and forward rotation by the right swing arm. Because of this asymmetrical design, when reclining rearward you will notice that the left rear end of the seat sinks slightly lower than the right rear end. This is because the right swing arm is supported by the forward rotational tension from the main spring for forward tilt, whereas the left swing arm is free to rotate only rearwards. To better understand the imbalance of tension, you may do the following test in the illustration below.

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Classic Pellicle Mesh vs Remastered 8Z Pellicle mesh

Improvements in the mesh is another major difference between the Aeron Classic and Remastered chairs. These improvements enhanced the durability of the seat, improved the comfort, and an overall better distribution of body weight over the Pellicle mesh material.

The material and manufacturer of the mesh material are kept the same for both the Aeron Classic and Aeron Remastered, using Hytrel Polymer by DuPont de Nemours Inc, and manufactured by Quantum Materials LLC. However, the process of how they are stretched over the frame has been reengineered to create the 8Z (8 Zone) Pellicle. Unlike any mesh chair in the market, the 8Z Pellicle is stretched to different tensions in different regions of the seat and back panels. The variable tension zones are engineered to serve different purposes, namely support, soften and stabilize. These tension zones allow the mesh to evenly distribute the user’s body weight, hence eliminating pressure points that causes sciatica pains common with users of the Aeron Classic.

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With the improved engineering in construction, Herman Miller has also eliminated the need for a foam cushion at the front edge of the Aeron Remastered. This foam on the Aeron Classic has been known to breakdown, disintegrate, and form a harvesting spot for dust mites and fleas. When purchasing the Aeron Classic from a pre-owned chair seller, it is important to check on the condition of its foam, and the existence of mites and fleas that may invade your home or office. Pre-owned chairs that causes redness, itchiness and patches on the under thighs are usually caused by mites and fleas from the foam padding.

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Industry standards of mesh durability rating is evaluated through the Wyzenbeek and Martindale abrasion tests. These tests measure the cycles of abrasions being put through the materials, reflecting their resistance to tear. The Aeron’s Pellicle mesh is measure with the Wyzenbeek method, and rated at 200,000 cycles of double abrasions, reflecting a total of 400,000 abrasion counts, whereas generic brands are usually rated at 50,000 double abrasion cycles. This best-in-class rating has been kept consistent from the Aeron Classic, to the Aeron Remastered, and it has been recognized as the benchmark in the seating industry.

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Changes in weaving on the mesh material has also been improved to increase contact comfort and reduce snags in the material. The tighter weaving allows creates a less abrasive texture on the material, and hence greater comfort on the skin when user is in shorts. The double strand weaving on the Aeron Remastered’s 8Z Pellicle reduces perforations on the mesh, hence decreasing the likelihood for snags and breakages by objects that may get caught in the material.

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Armrest Ergonomics

Armrest adjustments on the Aeron Classic armrest was previously limited to height and a 3-angle pivot adjustment. The improved 3-way armrest adjustments on the Aeron Remastered allows for an additional depth adjustment and increased precision on the pivot angles of the armrests. Having an additional depth adjustment allows the user to slide the armpads backwards to reduce obstruction, and sit closer to the desk for tasking purposes. The enhanced 9 angle pivot adjustment from the previous 3 angle adjustment allows a more precise adjustment of the armrests to fit the user better.

Back Support - Posturefit vs Posturefit SL

Known for their industry leading back support, the Aeron's PostureFit system is designed to provide lower spinal support in the sacrum instead of the more commonly found lumbar support in most generic ergonomic chairs. The transition to a sitting position from a standing position causes a rearwards rotational movement in the pelvis, and therefore directly changes the spinal curvature in the lumbar region L1 to L5. The sacrum being the mid point of connection between the pelvis and spine upwards from the lumbar, serves itself as the foundation of the entire spine, especially in the lumbar region. By providing support in the sacrum, the PostureFit prevents this rearwards rotation of the pelvis from causing the common C-shape slouching posture in the lumbar region, and puts the spine in its S-shaped natural state lumbar posture.

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In 2016 along with the collaboration from expert such as Dr. Walker, Herman Miller made further improvements to the PostureFit, and created the PostureFit SL (Sacral & Lumbar). The PostureFit SL included an additional support padding in the lumbar region, hence creating a more extensive vertical spinal support in contrast to the more common horizontal spinal support in most generic ergonomic chairs. These separate paddings allow for independent movement and flexes, with the sacral pad moving first and hence driving the lumbar pad to support the upper lumbar regions. This vertical back support system with depth adjustability further allows the user to fill the control the pressure of the support and hence generates a seamless fit to the contour of the user's spine.

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