Originally Posted by Inland RV Center, In
Upgrading to a higher load range should not be done on any wheel that has been in service for a period of time.
To do so imposses additional loads on that wheel, which will cause it to split around the circumference.
That information was published by wheel manufacturers some 25 years ago.
If the wheels are low mileage and relatively new, you can take the chance and upgrade.
The safest way is to replace the wheels.
There are a number of horror stories about people that have done exactly what your suggesting.
I will be happy to post a recent photo of just such a thing. The vehicle owner put a higher load range/pressure tire on a wheel, the edge of the wheel separated catastrophically. Stay tuned, I will snap a photo tomorrow at work.