Office Chair Adjustments Explained: Gas Lift, Tilt Lock, Rocking and Recline
By Furniture1004 min read
Underneath most office chairs is a small set of levers and knobs, and the listing describes them in a language of its own: gas lift, tilt lock, tension, rocking mode, recline. None of it is complicated once you know what each part does, and knowing it tells you which chair suits the way you actually work.
Here is each mechanism in plain terms, with the stated figures for our chairs.
Seat height: the gas lift
The gas lift is the cylinder under the seat that raises and lowers it. Press the lever and sit down to lower the seat; press it with your weight off the chair to raise it. It is what lets one chair suit different desks and different people, and it is why most desk chairs have one.
The number that matters on a listing is the height range. The stated ranges for some of ours:
A lower range suits a standard desk and a shorter person; a higher range suits a taller person or a higher desk. Most desks stand at roughly 72cm to 76cm. Sit with your feet flat on the floor, then check your forearms rest level with the desk. If they do not, the range is the thing to look at.
The Aero states that its gas lift is certified to SGS Grade 2. SGS is an independent testing body.
Fixed height
Some chairs have no gas lift at all, and that is a choice rather than a shortcoming. Without the mechanism, a chair looks far more like furniture, and there is nothing to sink over time.
- The Kasper has a stated fixed seat height of 48cm and a total height of 80cm, and swivels on a black metal base.
- The Ornix swivels a full 360 degrees on an X-shaped metal frame with no gas lift and no tilt.
With a fixed-height chair, check the stated seat height against your desk before you order, because you cannot adjust your way out of a mismatch.
Tilt, and the tilt lock
A tilting back leans with you when you sit back and returns when you sit up. The Denton and the Nash both tilt.
A tilt lock adds control. On the Otis and the Vaughn, a lever switches the back between locked upright and free to rock, and a tension knob sets how hard you have to lean before it gives. That is the difference between a chair that moves at the slightest shift and one that only moves when you mean it to. If you type upright for hours and lean back for calls, a tilt lock is worth having.
Rocking
A rocking back gives a gentle movement when you lean and settles when you sit up. The Aero has a rocking mode. The Aston rocks gently when you lean back, and the Oliver's backrest gives as you lean and returns as you sit up. It suits someone who likes a little movement through the day rather than sitting fixed.
Recline
Recline goes further than a rock. The Carter's backrest reclines from 90 degrees, bolt upright, to 135 degrees, well back, so you can type at one end and take a call at the other. Its headrest and armrests are both removable. It is the only chair in our office range with a stated recline range.
Castors, locking castors and feet
Most desk chairs roll on a five-point base with castors, which lets you turn to a shelf and back without getting up. On a hard floor, check the castors are the soft kind or use a mat.
Two variations are worth knowing about:
- Locking castors. The Nash's castors lock, so the chair stays put at the desk and rolls when you release them.
- Feet instead of wheels. The Ornix stands on an adjustable anti-slip pad on each leg, so it sits level on an uneven floor and does not creep.
Weight ratings
A weight rating is the maximum load the maker states the chair is built to take. The stated figures for ours: 125kg for the Aston, 136kg for the Ornix, and 150kg for the Carter and the Oliver. The Dexter and the Kasper are both stated at 300 pounds, which is roughly 136kg. The Aero's page gives test results instead: a push-back test at 102kg and a static pressure test at 950kg.
Which mechanism for which desk
- One person, one desk, on show in a living room: a fixed-height chair, or a gas lift with no tilt, looks the least like office equipment.
- A shared desk: a gas lift, so each person can set their own height.
- Long days of typing with calls in between: a tilt lock with tension control.
- A chair to lean right back in: the Carter's recline.
- A hard floor, or a chair that keeps rolling away: locking castors, or feet.
Find yours
Free UK delivery and 30-day returns on every chair, and you can Make an Offer on any of them.
For what the chairs are covered in, read our office chair materials guide, and for fitting one into a bedroom or an alcove, office chairs for a small home office. Or browse all the office chairs.
Frequently asked questions
What does a gas lift do on an office chair?
It is the cylinder under the seat that raises and lowers it. Press the lever and sit down to lower the seat; press it with your weight off the chair to raise it. It is what lets one chair suit different desks and different people.
What is a tilt lock?
A lever that switches the backrest between two modes: locked upright, or free to rock back as you lean. Our Otis and Vaughn both have one, along with a tension knob that sets how hard you have to lean before the back gives.
Which of your office chairs reclines?
The Carter. Its backrest reclines from 90 degrees to 135 degrees, and its headrest and armrests are both removable. It is the only chair in our office range with a stated recline range.
Do any of your office chairs have locking wheels?
Yes, the Nash. Its castors lock, so you can fix the chair in place at the desk and release it when you want to move.
What does the weight rating on an office chair mean?
It is the maximum load the maker states the chair is built to take. Ours range from 125kg for the Aston to 150kg for the Carter and the Oliver, with the Ornix at 136kg. Each figure is on the product page.
