Obscure question:

I want to build a tire swing, but I cannot find any plans or photos on the web. The tire swing I am talking about is the one that hangs from a tree branch with the tire laying horizontally, but the tire also spins. It has to have a mechanism that will allow the chain to spin at the top without it getting tangled. Any ideas?

Mount a tire on the bottom, then using chains & bolts, mount one about 4' higher with 3 chains. Use 3 chains into one to hang the assembly
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Find a hook from an old chain fall or come along. They spin [img]/phpBB/images/smiles/icon_smile.gif[/img] I bet ole F15 has something laying around in his shop.
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tire swings hurt

see if you can find a used funny car or rail car tire, spin fast enough and fit 3 peple in there [img]/phpBB/images/smiles/icon_spin.gif[/img]
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If you use chain you cant make it spin when you turn the tire i say use rope so you can go round n round

The ones I've seen have a bearing up top so the tire can rotate. I like the chain fall hook idea above. With the light load that the bearing will see, you could use virtually any bearing configuration without worrying about failure...a tapered roller would be ideal, a straight roller wouldn't work, a sealed ball bearing would, though.

Assuming you want to do this for very little cost, a trip to the junk yard should yeild enough parts to make a complete set-up. A hub and spindle would probably be a good part to start with...maybe one off a car with a Macpherson strut. That way you can cut the straight spindle shaft loose from the strut.

My $0.02.
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I guess you have not been looking very far...
but hey there is allways FordMuscle's garage to ask an "Obscure question"[img]/phpBB/images/smiles/icon_rolleyes.gif[/img]

This is what you need:

Heavy duty tyre swivel, three point mounting system, hardened steel ball with special ball bearings.
found at:
www.castlesintheiar.biz/pr_swingacc.htm

and:

Assembly kit to make a horizontal swing from an old used tyre.
found at :
www.tsthost.co.uk/catalog/index.php?cPath=25
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