About 15 or 20 years ago I found a tire bender in a flea market in really good shape, except for a missing crank handle, and soon after found a tire (or tyre) shrinker in a tailgate sale frozen with rust. I bought both of them thinking they might be nice antique display items.
With penetrating oil, heat, force and time I got the tire shrinker apart, cleaned and in good working condition. After it sat around a couple of years I got an offer I couldn’t refuse so I let it go. The tire bender worked well for making large rings and I used it a few times before it became a permanent fixture on the porch. It is one of a number of things I need to get rid of this year to make space.
Both of these tools served wheelwrights well. The American one-piece tire was made like this. The wood wheel perimeter was measured with a traveler and wrought iron of the appropriate width and length for the tire was forged. The ring of the tire was created with the bender and the junction was forged welded. The tire should be just a bit too small to fit the wheel cold but when heated it could be slipped on and quickly cooled with bucket after bucket of water shrinking and seizing around the wood. I’ve seen videos of this but never actually attended a live fitting.
I once visited a historic site where just out side the wheelwright shop there was a foot deep circular pit where a corncob fire was started and used to heat the entire circumference of the tyre. Next to it was a a worn out granite mill stone about six or seven feet in diameter where the wood wheel rested waiting for the fitting. Buckets of water would be placed around the stone ready for dumping.
This video shows a more modern version of the process.
The shrinker was used when a tire needed to be made smaller. After some use the tires would fret on the wood and wear it away and loosen. The tire could be knocked off and heated to forging temperature for several inches in an area which might have already been a bit thinned. When placed in the shrinker the dogs would grip the tire and upset it or buckle it slightly over an anvil plate and the tire would be hammered smooth again. When it was appropriately too small the whole tire could be heated and placed back on the wheel and cooled. I’ve never actually witnessed that either.