What is it? Set 260

On Sat, 29 Nov 2008 02:54:27 -0500, E Z Peaces cast forth these pearls of wisdom...:

Of course the circumfrance of a tire compresses. Don't over complicate this - simply let some air out of a tire and watch the circumfrance compress.

No need for all of this elboration to simply seat a bead.

Are you talking about big trucks? If so, they don't seat like a car tire. They use split rims. An entirely different manner of seating a tire.

Show this picture to one of the guys with a truck like this, and ask him what the ring is for!

--riverman

Take a good look next time you see a parked semi-truck . Namy are using tubeless tires and solid rims now , just like their smaller cousins . I believe radial tires are what makes this possible , because of the more flexible sidewalls .

At the center of the contact patch, the tread will be closer to the hub than before, but the tread will be as long as before. At the ends of the contact patch, the tread will be farther from the hub than before.

The subject has been discussed in rec.puzzles: will tire pressure affect speedometer readings? I got a surveying tape, parked on a level stretch of smooth pavement, and used masking tape and a plumb bob to mark the pavement below the center of the rear hub and the sidewall at that spot. Then I rolled exactly ten revolutions and measured exactly how far the hub had gone. (It was about 60 feet.)

Then I let air out until the hub was 10% closer to the pavement. I repeated the rolling experiment. One might say the radius had shrunk

Not even the weight of a vehicle will compress the length of a tire's tread enough for me to measure for sure on ordinary pavement.

It's simple when you can supply air fast enough to build pressure in spite of leaks. There are lots of patented tools to reduce the gaps enough to get a little pressure.

I was thinking of farm vehicles such as the two-ton truck in the photo. It was a man who had driven big rigs more than 30 years who said mechanics resorted to squeezing the circumference to seat beads on big-truck tires. It didn't occur to me to ask about split rims.

Clearly, the band in the photo was made as a welding guide. I suppose the similar tool the trucker had seen used to mount bias-ply tires had once been a welding guide. In the photo, I don't know if the welding guide was placed in the truck for welding, for tire mounting, or for some other use.

Senior moment . . . haven't seen any welders here this month. Had about 6 of them last winter. Norm

Mike Marlow wrote: ...

About 20-30 years ago or so... :)

Still have one old ('58) truck w/ 'em -- it's an experience when it's worked on these days as none of the tire shop working kids have ever seen one, what more worked on one.

Also a pita as it's got 8.25x20 and hardly anything is that small any more so have to pay full list to get something ordered for it.

On Sun, 30 Nov 2008 13:20:51 -0500, E Z Peaces cast forth these pearls of wisdom...:

Ahhh - now I see what you were referring to. Sorry - I could not take that out of your original statement. With this, I now agree with your earlier statement.