Tires: Tires for a Suburban...., medium duty truck, rv trailer

Question
I have an 88 Suburban R20 that was set up by the previous owner to tow his 14,000 RV trailer. It has an upgraded rear axle from a 4500/5500 series medium duty truck It is currently running LT235-75-R16 tires, and I generally run 50 psi front/60 psi rear when towing, and 45/50 psi all around for normal driving. I need to put new tires on it, and wondered what other sizes fit, as I might be willing to put heavier duty (stiffer) tires on it for better road wear and more safety. Any ideas ??

Answer
Tom,

First I am not going to be able to tell you what physical dimensions that tire has to have to prevent rubbing.  Not only would I need to measure the fenderwells are on your vehicle, but also, it has been modified.  So even the folks that measure that sort of thing - and who think the information gives them a competitive advantage, so they don’t share - would be guessing.

But some versions of 1988 Suburbans came with LT235/85R16's inflated to 44 psi front / 80 psi rear.

I suggest you load up both vehicles with as much stuff as you can ever think of using.  This would be "Worst Case".  If the trailer has water tanks, fill them all including the black water tank.  Then drive to a scale and weigh the combination - each corner if possible, but axle by axle at a minimum.

Take that number and add 15% and that should be the minimum load carrying capacity of the tire at the usage pressure.

And while you are at it, do the trailer, too!  Trailers are typically under tired.