alpine4us, here is a bit of 2006 information about tires. It includes most manufacturers and most sizes and postions. You may find it helpful in looking for your tire replacements. I found it very useful in identifying replacements for our coach because the load info is included.
Steering tires and all position tires appear to be the same quality and capacity. There is a distinct difference in drive tires and steering/all position tires. As noted already, the construction for those is different than the steering/all position tires.
I replaced all of our tires with Continental HSLs which are steering/all position. Might have gotten off cheaper by putting drive tires on the rear axle, but in the event I need to rotate tires (don't see that happening, but it could) I would have better options than if I had drive tires on the rear axle.
http://www.randallpub.com/overdrive/..._specs_new.pdf