Excerpt from Bridgestone Tire Company
Generally, the dual load rating is about 5 to 10 percent less than the single load rating.
Does the difference between dual and single loads compensate if a tire in a dual assembly goes flat?
Unfortunately not. The second tire in a dual assembly is not a spare. It cannot take up the slack if you have a flat.
The remaining tire can’t safely take on the load that was previously on two tires. And, if you run your tires at lower inflation pressures, the overload would be even greater.
Just a friendly word of caution