Tires: tire size, dual tires, tire failure

Question
I have a 1999 Fleetwood with 225 75 16 tires on it. That is what the door label calls for. I was wondering if I could go to 235 75 16 tires. I have seen other rv's that have done this. Its not much of a difference in size, but the load they can carry can be quite a bit higher. I'm concerned about how close the dual tires can be without causing problems. Thank you.

Answer
Don,

If you look carefully, the door label says the tire size should be LT225/75R16.  The tire size you are considering is a P235/75R16.

The difference between and LT type tires and a P type tires is like the difference between your RV and a car.

DO NOT - repeat - DO NOT make this change.

The load carrying capacity of the P235/75R16 is not enough for your RV and a load related tire failure would be quite likely.

(BTW, you may not be aware of it, but P metric tires have to be derated 10% when used in a light truck application.)