/diy/ - Do It Yourself

I'm gonna buy a pair of carriage wheels with a metal axle, but i'm thinking that they might not be strong enough for what i'm doing
they need to hold around 600-800 pounds, with just one pair of wheels with a 48" diameter
how could i reinforce it to prevent it from breaking? the website doesnt say what weight they're rated for but i'm assuming that since it should hold up a carriage it should be enough to hold what i need
the wheels are basically the same design as in the picture, only they have steel rims instead of rubber ones