I am building a Sig 4* .40 size, the kit calls for 2-3/4 wheels. Wanting to know what the difference between foam, and rubber wheels is? also i noticed that DU-BRO offers Treadded Rubber, and Smooth Rubber whats the difference between these two? Anybody got recomendations on what brand is better than the next?

sky lites are very light in weight most of the dubro tire are pretty heavy especially as the size goes up. foam wheel are just that (foam).

Foam tires are often lighter than rubber. If they’re open cell foam, they tend to absorb fluids (spilled fuel, water, etc) and pick up dirt. Some of the foam tires have a rubber skin to prevent this and to make them look more like full size tires.

Dave brown foam wheels are very light but I do not like the way they look.

Treaded tires look more like full size tires than smooth ones do.

I don’t know if they’re better or worse than any other brand; I like the Hangar 9 Pro-Lite offerings as well as any. I think they’re rubber coated foam but I’m not sure.
http://www.horizonhobby.com/Stores/P...PW&BrandId=HAN
Dubro and Great Planes use a small diameter wheel with a really fat tire around it. The Hangar 9s look more realistic (to me) because the wheel and tire seem to be the right size.

this is me speculating... foam tyres are the lightest, but they kinda need a really neat runway otherwise they get chunks chipped out of them, also they have more resistance when you are rolling on them, but they are not prone to being stretched into a pizza cutter shape by the centrifugal force when the wheels are spinning really quickly

smooth rubber tyres are tougher, heavier , and offer the least resistance , and you can use them on many surfaces....

the treaded tires are there for looks i guess, the treads hammering the ground will slow it down, also there is a possibility that the treads could pick up debris from the ground and fling it at the underside of the fuselage

the weight of the tyre is important not only in-flight, but also at the instant that you touch down, the tyres will have to suddenly be spun at the groundspeed of the plane, the lighter it is the easier it is to do so
or am i wrong on any of these points?

Foam tires save weight because they are lighter than rubber tires. I have found that on a grass field, which is what I fly on, rubber tires perform better ie: they absorb shock better than the foam. For a normal size 4 channel sport plane, the added weight of rubber tires is well worth it.
One use of a treaded tire is for added traction for steering when used as the nose wheel.

you can get foam in treaded smooth almost any size,rubber tires are more durable and can handle more weight.