OK, we've done the "How do the spokes support the hub?" question to death.

Now: How does the tire support the rim? If I have a force of 100 lbs "pushing" down on the rim from the spokes, where does the load "go" to get to the tire contact patch?

Air pressure on the inside of the rim?

Load at the bead? How is it distributed? Where does it come from?

(Not Actual Size)

There are millions of these gnomes in your tubes. They are in suspended animation, but come to life when you inflate the tube. Their mass is nearly nil, so they can move at near the speed of light. They shuttle force particles around constantly in their wheelbarrows, moving it away from the contact patch so the tube/tire doesn't explode from the massive buildup of energies.

The tire supports the rim by just being there for it when the road gets rough.

good ones!

Here are two truths that I think are pretty obvious, or at least well-known.

1) The volume of the tire (and the pressure) don't change much when the tire is loaded.

2) The load "goes" from the contact patch to the bottom of the rim. That is, a loaded wheel is flatter on the bottom. We know this because the bottom spokes "compress" or un-stretch more than the top spokes stretch.

With kind words and a supportive attitude, of course.

Oh, just realized I was late to this party.

I think the tire doesn't actually "push" up on the rim.

An unloaded, inflated tire has a pressure load (stress) on the rim directed radially inward. This load is exactly counterbalanced by the radial component of the tension in the tire casing.

On a loaded tire, the casing (somehow) loses some of that radial tension stress when it deforms at the contact patch. Maybe.

Actually, I would much prefer to have talking tires, that would be cool. Sort of like the boy that found the talking frog. Frog tells the boy that if he kisses it, the frog will turn into the woman of his dreams and fulfill all his desires, so the boy reaches down, picks up the frog and puts it in his pocket. The frog asks the boy, didn't you hear what I said? Sure, says the boy, but I would rather have a talking frog.

Either the pressure or volume (or both) has to change. Or are you saying the changes are negligible?

Yes, I think the changes are negligible. What do you think?

Doesn't the wheel actually hang from the upper spokes more than stand on the lower spokes? I've always thought that gnome deal was true. Now I can tell all of my friends. All two of um.

I'd guess the change in pressure is pretty negligible. Since the appropriate tire pressure chart on sheldon brown's page seems to specify some amount of compression as being the starting point for picking a pressure i think the volume might be significant, depending on why you care.

The change in tension in the lower spokes is greater. Because the spokes only act in tension, i would say that hanging is a more accurate term. There are already 5 pages of people debating this in another thread though.

Edit for Clarity: The change in loading over the whole wheel is 0, the compressive loading is distributed over fewer spokes than the tensile loading.

I put helium in my tires, so the top of the tire supports the rim which is hanging to it. That's why they have to be clinchers.

Undoubtedly P&R.

My thinking is because the spokes do not bolt to the wheel. Therefore, the all spokes are virtually useless until they rotate to the top.

the tire and the rim are the same
























on the quantum level

This thread is about TIRES. Not spokes!

Physics & Reality?

Isn't P&R for arguing? I was sure it was/is.

I thought the purpose of BF was to argue.

Not sure if this applies, but this thread might help answer the OP's question. Although, you'll have to scroll through some... ugh... arguments.

you people are silly

put that to music.

All this is nothing but semantics.