... i guess a bias ply would be better than nothing. I'll check into it.
The bias ply is considerably "better than nothing" especially when compared to a space saver. Most of them have written right on the side of them they are only for temporary use with a limited amount of miles.
You should also be concerned about the weight of your truck, vs. the weight the space saver was designed for.
Why re-engineer what your truck was originally engineered for
