[turnipsock (OP)]

Why do office chair always have five wheels?



I'm fed up banging my heels.

[lightarrow]

Why do office chair always have five wheels?
I'm fed up banging my heels.

What is it? A word play?   []

I venture a guess: 3 or 4 wheels would not be enough to prevent it to overturn under the sitter's weight when displaced over the space bewtween two wheels (personal experience  []).

More than 5 would be more expensive and so meaningless.

[Chemistry4me]

Ha! I didn't even notice I was sitting on one all this time! With five wheels you can put your feet on two of them, with only four it is a bit of a struggle.

[turnipsock (OP)]

...but old office chairs had four legs.



and I seem to remember we had one that had three legs, sure the legs stick out a bit more but why settle on five?

[JnA]

Probably because five is the number that dictates what is safe (on a number of surfaces) and cost effective.

[lightarrow]

To have a safe chair with four wheels (and you don't have to go back many years, just ~ 10) you have to make it too heavy.

[Steph]

I'd opt for safety. My first office chair was a 3-wheeler, and it was always falling over. Sometimes with me on it  [] You just can't safely spin around in circles on 3 wheels...

[Chemistry4me]

Or if you're having a race with your friend who happens to have five wheels.
Still, five wheels = more resistance right? []

[Don_1]

I blame decimalisation.

5 Wheels on my office chair,
And I'm still rolling along.
Those chairs and keys,
Don't bother me.
My printer's bust,
Smothered in dust,
But I'm still rolling along,

4 Wheels on my office chair,
And I'm still rolling along.
Those DVDs,
Don't bother me.
CD's cracked,
I'm feeling whacked,
But I'm still rolling along.

3 Wheels on my office chair,
And still rolling along.
My screen has froze,
I'm beginning to doze.
Serial bus,
Covered in puss.
But I'm still rolling along.

2 Wheels on my office chair,
And I'm still rolling along.
My optical mouse,
Has caught a louse.
Connection down,
Hub not found.
But I'm still rolling along.

1 Wheel on my office chair,
And I'm still rolling along.
My hard drive,
Just took a dive.
File not found,
It's gone to ground.
But I'm still rolling along.

No wheels on my office chair,
So I'm not rolling along.
The central pole,
Shot up my a***hole.
No more smiles,
Now I've got piles.
And I've stopped rolling along.

[Bored chemist]

Thanks for that, best giggle I have had in a while.

[LeeE]

Wheeled chairs have a minimum of five wheels for safety reasons.  Because the chair is on wheels it is assumed that people will 'scoot' on them (for short distances) rather than get up and walk, but because the 'scooting' force is applied sideways, to the end of a long arm, the force tends to topple the chair as much as it propels it.  While the wheels are on a smooth surface there are few problems but if someone hits a ridge in the floor, such a rug or a raised floor vent, the chair is much more likely to topple than roll.  This is made even worse by the fact that the wheeled base can rotate freely, so once one wheel has struck a ridge and stopped, the wheeled base is likely to rotate until a second wheel hits the ridge and when this happens the effective wheelbase is no longer twice the arm length but only sin/cos 45 deg of the wheelbase i.e. it is reduced by a factor of 0.7071067.  Increasing the number of wheeled arms on the base mitigates against this.

[lyner]

Turnipsock
I'm sure you can afford an upgrade!

[GulaLai]

Why do office chair always have five wheels?



I'm fed up banging my heels.

It enables the chair operator to move around quickly and efficiently. Castor wheels are usually set into a '5 star base' to give the best support and balance, and are popular on 'operator' chairs, 'executive operator chairs', lab chairs and ergonomic chairs where the operator needs to perform different tasks in different parts of their working area.

A castor base also adheres to the ergonomic principle of supported, easy movement. Also to move around the room

[Colin2B]

Why do office chair always have five wheels?

I'm fed up banging my heels.

Thinking about this, it’s a simple geometry problem so you can see why 5 wheels offer optimum stability for a given radius of wheels.
Take a circle and inscribe it with a triangle, square and a pentagon. The points of these figures are where you would place the wheels. If you draw lines joining the points of each figure the shortest distance from the circle centre to those lines represents the stability of each wheel arrangement - the chair becomes unstable when the centre of mass goes outside one of those lines.
So, you can now see that for a given footprint (circle diameter) the triangle is least stable, then square, but pentagon most stable. Interestingly a hexagon is only slightly more stable.

[edulofter]

The chair in my office has 4 wheels. Is it cost effective? Still cutting corners?

[Rasull]

Four wheels are enough for office chairs, for more protection and safety and to handle more weight five wheels are used in chairs.

[Karl F]

Office chairs do have 5 wheels to provide better comfort and balance, so that you can move around place easily.

[martingail11]

What is this? Old office chairs had four legs but nowadays legs are four or five either.

[Zymurgy]

Nowadays, most of the executive office chairs have castor wheels that are having a five-star base. These caster wheels in the office chairs provide better comfort and balance. With these wheels you can move around the place easily and possible of 360-degree rotation.

[syhprum]

The aliens who originally designed them were inhabitants of Rama, it is well known from the book "Return to Rama" that the technologically advanced inhabitants that designed space ships had three legs what is not so well known that there was a race of five legged people not so well advanced to whom more mundane work was allocated