Most people understand the importance of making sure their office chair is suited to their height and weight and know roughly what to look for when buying a new chair, but some of the features can be confusing.
This guide is to help you buy the right chair for your need, and explains main functions and features you are likely to find in the office chair market.

To being with, all operator chairs will have a 5 star base on castors, and a central pneumatic ram, which allows the user of the chair to adjust the height of the seat base between 40 and 55 centimetres, just by moving a lever.  This is the most basic office chair, and really doesn’t provide enough adjustability for continual use.

Nowadays even the most basic of chairs will have a backrest that is rake adjustable, although at the budget end this will be by means of a friction clamp, which needs to be released, to allow the backrest to be moved to the desired position, and then tightened up again. This clamp is usually under the chair base and difficult to reach.

So ignoring this method of backrest adjustment the main options you will be presented with are as follows :-

Permanent contact backrest ( PCB) – This is similar to the friction clamp mentioned above, except that the backrest is unlocked with a lever under the seat. The backrest can be left in the unlocked position if preferred, and a spring tension handwheel under the seat adjusts the amount of force that backrest applies to your back. Most users however, just lock the backrest in the position they find most comfortable, preferring this to having  a free floating backrest.

Synchronous Mechanism. This is slightly more expensive that the basic PCB mechanism, as the backrest and seat base are linked so that the seat-base tilts backwards in relation to the angle of rake of the backrest.  By linking the two, the chair feels more comfortable when left in the free floating position, as the seat base tilts when the backrest does.

The chair then does what it was designed to do, which is provide the user with some support, whilst still allowing the user to alter their position in the chair. Using your office chair in this way is recommended by most specialists in the field. A fixed backrest only encourages bad posture, as the user tends to just slump into the chair. Also the nature of office work  makes having a free floating backrest essential.

One minute you are sitting upright, using your keyboard and screen, and the next you are leaning back into the chair, taking a phone call or reading some literature. A free floating backrest will provide you with constant support in every situation, unlike a backrest which is fixed in one position.

Asynchronous Mechanism.  This feature allows both the backrest and seat-base rake to be adjusted, by means of separate levers, and independently to each other. Using the chair in the free floating position is not as comfortable as with a synchronous mechanism, but the advantage is that the seat-base  can be locked in a variety of positions, including being tilted forward, which is often preferred when using the computer for longer periods of time.

DoubleSync Mechanism. The Rolls Royce of seat back mechanisms. All the advantages of a fully synchro mechanism, but with an additional lever which allows the seat-base to backrest relationship to be altered.  You can tip the base forward, independently to the backrest, lock in it in this positions and then move another lever, to switch to the free floating synchronous mechanism.

These are the main options with regard to backrest adjustment on office chairs, and most office furniture showrooms will have examples of each mechanism for you to try.
The difference in price for each mechanisms is not that great when you consider how long you might keep the chair, how many hours you spend sitting in it, and how valuable your back is.
So don’t delay – Contact your office chair dealer today