Updated: Nov 6th, 2020
When it comes to tilt mechanisms on office chairs, there are many types, and selecting the right one can make all the difference for long term comfort.
From single point pivot, synchronous tilt, to knee tilt, while each tilt mechanism reclines the backrest of a chair, the difference in experience can be dramatic, and as such, has a direct bearing on comfort as well. Let’s take a look at all the major tilt mechanisms out there, and how to pick the best one for your needs.
This article is part of our “Choosing an Ergonomic Office Chairs” Series:
- What is Seat Pan?
- Synchro Tilt and Other Tilt Mechanisms in an Office Chair Explained
- Types of Lumbar Support for Office Chairs (and What to Choose)
- Armrests on Ergonomic Office Chairs- What You Need to Know
If you’ve ever shopped for an ergonomic chair before, undoubtedly you’ve seen this feature mentioned, especially in higher end chairs. So just what is synco tilt?
In Synchronous tilt, the backrest and seat pan of a chair reclines at a different ratio (usually 2:1) as you lean back. For every 10 degrees of recline in the backrest for example, the seat pan only tilts back 5 degrees.
Ergonomic Rating: Good
Analysis: Synchro tilt provides quite a few ergonomic benefits and should be the de facto choice when picking out an office chair:
- Minimizes the seat pan rise as you tilt, allowing your feet to remain on the floor while your gaze remains straight ahead
- Stretches the chest without applying excess pressure on your thighs
Single Point Tilt
Typically found on less expensive office chairs, single point tilt employs a basic tilt mechanism that’s located in the center or back of the seat to tilt the seat pan and backrest in tandem. The recline ratio is usually the same.
Ergonomic Rating: Basic
Analysis: Single point tilt is generally not recommended for any chair that tilts more than 5-10 degrees backwards. In a single point tilt, the angle of the front of the seat increases at the same rate as the backrest, leading to increasing pressure in the underside of your thighs as you recline. It also exasperates the feeling of falling backwards.
With Knee tilt, the pivoting point is located near the very front of the seat, resulting in a wide angle tilt that still keeps the front of the seat relatively level. This type of tilt is usually found on conference room and executive chairs, such as the Flash Furniture executive chair.
Ergonomic Rating: Basic to good
Analysis: Knee tilt combines some qualities of synchro and basic single point tilting. With the pivoting point near the front of the seat, your feet remains on the ground even with a larger recline in the seat pan and backrest. Due to the location of the mechanism however, knee tilting chairs usually lack more advanced ergonomic features such as seat depth adjustment.
In forward tilt, the edge of the seat pan is able to dip below the horizon around 5 degrees as you lean forward and apply pressure. The Herman Miller Aeron is among one of the few chairs with this extra mechanism.
Ergonomic Rating: Excellent
Analysis: Forward tilting is a great ergonomic asset for people who tend to sit at the edge of their seat or lean forward a lot. According to OSHA, a forward sloping seat pan helps increase blood flow to the lower extremities all the while reducing lower back pressure and pain in the forward leaning position.
Forward tilting seldom exists by itself in a chair, and is typically found as part of a multi-tilt mechanism to provide a balanced range of adjustments. Currently few ergonomic chairs on the market support forward tilt. The Herman Miller Aeron and some of its alternatives are among the elusive list that do.
With forward gliding, the seat pan actually shifts forward and down as the backrest reclines. Such a mechanism can be found in the Steelcase Leap Chair, for example.
Ergonomic Rating: Good
Analysis: Forward glide goes against how most tilt mechanisms in an office chair work. Instead of reclining backwards, the seat pan moves in the opposite direction and downwards in relationship to the recline angle of the backrest.
Forward glide can be advantageous in that it keeps your lower body in a constant flat to slightly downwards sloping angle. It enables your arms and gaze to comfortably stay within the work zone even with a heavily reclined backrest, which is great for people with back pain where the ideal backrest angle is around 135 degrees.
Multifunction Tilt Mechanism
Multifunction tilt, or asynchronous tilt, refers to a mechanism where the backrest and seat on the chair can be tilted independently of each other. This lets you customize the exact angle of the two components to find the most comfortable sitting posture.
Ergonomic Rating: Excellent
Analysis: Multifunction tilt in theory offers the best level of ergonomics, though the added levers and time required to find the perfect angles for both parts needs to be taken into consideration. If you’re not happy with the tilt mechanism found in synchronous tilt or forward glide, this is a next logical step to try.
An affordable office chair with asynchronous tilting is the Hon Network Task Chair.
Seat Angle Lock
Finally, there are chairs that come with seat angle lock. which is great for working in a highly reclined position, by angling your whole body upwards, and not just your back.
Let me explain.
Whichever type of tilt an office chair comes with – synchronous, knee tilt ectara – typically only the angle of the backrest itself can be locked in. The seat angle once you stop applying pressure to the backrest reverts to a flat angle:
In chairs with seat angle lock, the angle of the seat as it points upwards (when you recline the backrest) can also be locked in:
The biggest advantage of such a feature is that it facilitates working in a highly reclined position from time to time, which greatly reduces back pressure.
Here is me in the Andaseat Kaiser using seat tilt lock to do just that: