RV Tires...

[345 desoto]

I have been going around and around for about a week now, looking for good, SAFE, replacement front tires for my '88 Chieftain, and I am more confused now than when I started. My GVA is 12,300lb...I have NO idea what that means. My GAWR for my front is 4,880lbs, and rear is 7,550lbs, I don't know what THIS means, either. It currently has 235/85R16 Firestone Steelflex LT tires on it (BRAND NEW...in 1988!). Can I SAFELY use LT's on it, or do I need a heavier duty tire. It is obviously NOT an LT (light truck). Current Firestones have 2 ply steel tread, and 2 ply polyester side walls. Is this adequate?... We will be driving it from central NYS to south Florida, and I do NOT look forward to a blow out(s) @ 60-65 MPH...

[Podivin]

Smarter people than me will jump in, but here's what *I* would do.
Your front axle is rated for 5000 lbs (yep, I rounded up because the rest of the math will be easier). So each tire needs to have a LEAST a max load rating of 2500 lbs (each tires carries half the load). So now I would add at least 10% margin for safety and probably more like 20% - minimum.
At 10% you're at a load rating of 2750, at 20% it's 3000 lbs.
So now, find tires in your size with a load rating of at least that much, that will answer the question about whether or not an LT tire will safely carry the load.

The calculations for the rear are the same, but you've got 4 tires (I assume) sharing the load instead of 2, so do the math accordingly.

[macnut]

My advice would be to pack the RV as you would when traveling and get the axles (or if you can, each corner) weighed. You can then make the right choice for tires and air pressure. All manufacturers provide guides for air pressure based upon the load.