Re: Exactly what is the "foam" in foam filled tires
I believe there to be many different "fills" that the tires are filled with. No different then there are many different "foams" out there.
My personal experience was we were knocking the tires off the rim constantly on our Pro Master 100 Gravely ZTR (not enough trail in the casters in my opinion) but the tire would be sideways, then you would go forward and basicly drive the tire off the rim, worked better then any bead breaker I have owned, and always at the most inoppurtune moments and locations. It was also a true bugger to get them to take air at those moments and re-inflate.
As I wanted to be "done" with this problem, I took them to the local tire shop that handled "foam filling" of the tires, and they "filled" them, quite expensive and quite heavy, and had about zero "give" The tires ended up being like a solid rubber tire, in other words not foamy and squishy, but solid.
How did that work out,,,,, NOT SO WELL......
Wheel bearings, yep, instead of having the suspension that the air in the tires gives, you directly transferred a lot of the shock loads direct to the bearings, commenced to chewing them out.
Caster yokes,,,, yep, started bending the crud out of them, at $125 a pop that got old REAL FAST.
Finally ended up buying new wheels, yokes, tires, and adding tubes.
If you look at skidsteer tires there are solid ones that are like forklift solid tires, hard rubber, then there are the ones that have holes drilled through them horizontally so they have "give" for the offroad use. (I was told that the solid rubber ones transmit a lot more shock to the driveline) and I believe it.
I bet there are many types of foam to fill the tires with, just as there are many brands of puncture seal such as slime, and I bet many of our different results have to do with the product that was used.