Can ST225/75R15 Trailer Tires be Replaced with ST235/85R16 Tires
Question:
Im thinking of upgrading to this size tires and wheels. My RV is 10000gvw and currently has st225/75r15. The owners information manual says to run tires at 65 psi which is the max pressure of the current tires. If I go to these, will I still use 65 psi? Also the video said these rims have 1/2 inch positive offset while the specs say they have a 5mm positive offset. It makes a difference in my measuring. No hurry on an answer. This is a fall project. Thanks
asked by: Bill F
Expert Reply:
If you go with tire and wheel combo # AM32734 then you would fill the tires to 95 psi. The psi rating goes with the tire and wheel being used and is not specific to the trailer itself.
I checked with the manufacturer of the wheel and they show it as having a 5mm positive offset.
Going to a larger tire and wheel size is fine as long as the trailer has room for the larger size. An ST225/75R15 tire that you have now is 28.4 inches tall and 8.78 inches wide. The larger ST235/85R16 tire, such as # AM32734, is 31.67 inches tall and 9.37 inches wide. So there will need to be enough clearance all around the existing tires for the 3.27 inch tall and 0.59 inch wider tire.
