What is this pin for?

[AberdeenAngus]

I can handle being wrong, unlike many of the flat earthers on the site.

Can you remind how objects stay in orbit around the earth, please?

For things in orbit, the force toward the centre is indeed caused by gravity. We were talking about wheels.

 

[AberdeenAngus]

Except it wasn't me who said that - just the quoting attribution on here seems to be screwed at the moment. Here is the original:



So please direct your comments to the actual author of that statement!


My original reply to ChazzyB's comment was:

"I didn't say what the force towards the centre (centripetal force) was caused by, just that it exists, unlike the imaginary centrifugal force.

I suppose in the case of the earth orbiting the sun you would be correct to say the force towards the centre is gravitational attraction (though let's not get into exactly what that is!). In the case of a rotating wheel I would say that what stops bits of the wheel rim flying off at a tangent is not gravity but the restraining force exerted by the spokes linking rim to hub - at least until they fail!"

In post #57, you can see that I was indeed responding to a comment by ChazzyB. You can tell because in the quoted section, above my reply, it says “Originally posted by ChazzyB”.

 

[fred_jb]

In post #57, you can see that I was indeed responding to a comment by ChazzyB. You can tell because in the quoted section, above my reply, it says “Originally posted by ChazzyB”.

Yes, I agree that it now looks right, but I think it may have been corrected after I reported the problem to one of the mods. He said it was due to an accidental editing error further up the thread that caused subsequent quotes to be displayed incorrectly.

 

[iandavid]

You really do have to wonder how some people manage to own and ride a bike. The clue was in the valve cap on a wheel that is pumped up with air via said valve cap. They really do walk amongst us.

 

[ChazzyB]

For things in orbit, the force toward the centre is indeed caused by gravity. We were talking about wheels.

So what's the *inward* acting force in a spinning wheel?

 

[millsy]

Listen mate, i never noticed the valve cap, it was only afterwards looking back at the photo, so if i was you, i would concentrate on my own riding and ownership, instead of being another smart *rsed patronising know it all.

 

[millsy]

You really do have to wonder how some people manage to own and ride a bike. The clue was in the valve cap on a wheel that is pumped up with air via said valve cap. They really do walk amongst us.

Listen mate, i never noticed the valve cap, it was only afterwards looking back at the photo, so if i was you, i would concentrate on my own riding and ownership, instead of being another smart *rsed patronising know it all.

And as for "they" walking amongst us, who the hell do you think your talking to?

 

[Martin S]

Listen mate, i never noticed the valve cap, it was only afterwards looking back at the photo, so if i was you, i would concentrate on my own riding and ownership, instead of being another smart *rsed patronising know it all.

And as for "they" walking amongst us, who the hell do you think your talking to?

Well said.

 

[fred_jb]

So what's the *inward* acting force in a spinning wheel?

The spokes, be they alloy or wire, resist the tendency for each part of the rim to fly off at a tangent. Just because the rim is a single part it does not mean that each atom of it is not subject to the laws of physics which state that unless acted on by a force an object will either stay at rest, or if moving will continue to move in a straight line at its original speed. In order for all these atoms to continually change direction so as to move in a circular path, it means that a force towards the centre of that circular path is being exerted.

It is just the same as a spinning playground roundabout. So long as you use your arms to hold on, you stay on the platform, but if you release your hold you fly off. Change arms for spokes and you have the same thing with wheels.

 

[ChazzyB]

The spokes, be they alloy or wire, resist the tendency for each part of the rim to fly off at a tangent. Just because the rim is a single part it does not mean that each atom of it is not subject to the laws of physics which state that unless acted on by a force an object will either stay at rest, or if moving will continue to move in a straight line at its original speed. In order for all these atoms to continually change direction so as to move in a circular path, it means that a force towards the centre of that circular path is being exerted.

It is just the same as a spinning playground roundabout. So long as you use your arms to hold on, you stay on the platform, but if you release your hold you fly off. Change arms for spokes and you have the same thing with wheels.

So it's nothing to do with the dust cap holding it all together then?

 

[fred_jb]

So it's nothing to do with the dust cap holding it all together then?

 

[AberdeenAngus]

So what's the *inward* acting force in a spinning wheel?

Tension of the spokes.

 

[AberdeenAngus]

Listen mate, i never noticed the valve cap, it was only afterwards looking back at the photo, so if i was you, i would concentrate on my own riding and ownership, instead of being another smart *rsed patronising know it all.

And as for "they" walking amongst us, who the hell do you think your talking to?

Send him your phone number.......though I think you’d be better off smiling and taking it on the chin. It’s just a bit of piss taking

 

[Piggers]

forces

Are we saying that the centrifugal force is enough to distort the rubber seal around the post and this is where the air leaks from or is the suggestion the the force is enough to force the valve spring down letting the air out ? If the second,no dust cap fitted would let the air out, but if a dust cap was fitted the forces acting on that (especially if a heaver type - metal) may be enough to seal the the top of the stem (probably aided by the force from it being tightened) and help prevent the loss of air.
Can someone with a rolling road and a high speed camera please carry out an experiment and let us know at what speed we need to worry.....

Cheers

 

[AberdeenAngus]

Are we saying that the centrifugal force is enough to distort the rubber seal around the post and this is where the air leaks from or is the suggestion the the force is enough to force the valve spring down letting the air out ? If the second,no dust cap fitted would let the air out, but if a dust cap was fitted the forces acting on that (especially if a heaver type - metal) may be enough to seal the the top of the stem (probably aided by the force from it being tightened) and help prevent the loss of air.
Can someone with a rolling road and a high speed camera please carry out an experiment and let us know at what speed we need to worry.....

Cheers

Somebody thought it might be enough to distort the valve, some thought it enough to depress the valve, others disagree.
The discussion became very involved.
Somebody felt insulted and called somebody else ‘mate’.
Such is UKGSER.

 

[Tractors are go]

Are we saying that the centrifugal force is enough to distort the rubber seal around the post and this is where the air leaks from or is the suggestion the the force is enough to force the valve spring down letting the air out ? If the second,no dust cap fitted would let the air out, but if a dust cap was fitted the forces acting on that (especially if a heaver type - metal) may be enough to seal the the top of the stem (probably aided by the force from it being tightened) and help prevent the loss of air.
Can someone with a rolling road and a high speed camera please carry out an experiment and let us know at what speed we need to worry.....

Cheers

Porsche did one years ago; to explain why you shouldn't use rubber valves but metal ones.

It was scary watching it bend. After that none of my cars have rubber valves.

There is the argument that as a motorcycle tyre valve is central in the wheel, any centrifugal force is at a tangent.

Personally for the extra couple of quid metal one's cost, it gives me peace of mind.



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[Piggers]

I'm from Essex, so I call everyone Mate

 

[Tractors are go]

I'm from Essex, so I call everyone Mate

Excellent

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[ChazzyB]

Tension of the spokes.

And on a GSA?

 

[iandavid]

Listen mate, i never noticed the valve cap, it was only afterwards looking back at the photo, so if i was you, i would concentrate on my own riding and ownership, instead of being another smart *rsed patronising know it all.

And as for "they" walking amongst us, who the hell do you think your talking to?

Someone who hasn’t got a clue about bikes. If you had done any research, visited a bike showroom, looked on google you’d have known about valves in spokes.