Forklift guys- What exactly is a "solid pneumatic" tire ?

Is it a regular pneumatic tire filled with foam, or is it just a larger diameter version of a cushion tire ? or something else altogether ?

Reason I ask is I assumed it was a pneumatic tire filled with foam, but I keep seeing used lift trucks with those type of tires where there are major chunks broken off the tire edges and often cracks in the sidewalls, just like worn cushion tires.

But if it's really just a high profile cushion, how is it they can run on dirt without getting stuck ? Which brings up another question...will they run on dirt just as well as a standard pneumatic, or do they tend to get stuck more often ?

I have a mid 80's CAT 6K fork lift that is a pneumatic truck.(I forget its actual model number) The tires are filled, urethane foam, I think. My tires look as if they were recapped, like a truck tire, I would swear that they were capped. They have all sorts of dings and bangs in them, but no big chunks like a cushion tire. The truck is somewhat better on dirt than a pure cushion tire but not a lot. You loose the advantage of the tires acting like suspension, giving and flexing. What you do gain is added ground clearance, larger diameter wheels. Besides its not fun to move machinery with air filled tires! Filled tires have there place, out of the 6 or 7 lift trucks I have I do have one...

That's a contradiction in terms. I've heard of pneumatic, semi-pneumatic and solid. Solid pneumatic would mean a solid tire that takes air?

At the wiremill I worked at, I drove a Hyster that came with air in the tires. Hard rubber, but still air. We would send them out and have them filled with a type of foam that lasted a while, but not like solid ones. However, it rode better than solid tires, and did offroad a lot better.
David from jax

A solid pneumatic tire is a solid rubber tire of the comparable size of an air filled type tire. It is pressed onto the pneumatic rim and is "supposed" to have the same characteristics as to ride, etc. as a pneumatic with a tire pressure of 110 psi, However that said, there are many brands out there and they are not all the same. Some have different durometer layers to give better ride and wear. Also tread patterns differ for traction, Some are known to spin on the rim, thus needing stock welded to the rim to eliminate this problem. They also add weight to the truck for better stability but not something you can sell. Most users run the tire well beyond is proper wear level and get into problems with low underclearance, rough ride and lousy traction. GOOD FOR SCRAP YARDS and rough applications where they tear the truck up anyway.Dick.

David, "lasted a while" means what...a month, two years, or ? What happened...did they gradually go flat or have sudden failures of some sort ?

Heres a picture of my Cat I have had alot of load on this truck and the tires do not flex one bit. I have had this truck about 7 years and never had a tire problem. I even plowed snow with it, and had tire chains on it

[This message has been edited by Tom1 (edited 07-28-2004).]