Tires: Tire Size, size rim width, tire placard

Question
I just purchased a 94 Ram 1500 that needs tires. Current tires are LT245/75R/16, which are incorrect(1/2 ton and 3/4 ton 4x4).The door placard reads P225/75R/16 XL,35psi front, 41psi rear.In the Tire Inflation Chart that came with the owners manual,The tires listed for the 6400 GVW Ram 1500, are the P225/75R/16 XL and the P245/75/R16. Are both suitable even though there is a 4% difference in diameter? The spare is a P245/75R/16. I assume the 245's are the printed option,but why isn't the option stated on the placard? Any info would be greatly appreciated. Thanks

Answer
Steve,

I find it odd and confusing how Chrysler handles vehicle tire placards.  On the one side, they are obligated by law to have one on each vehicle they produce, and it has to have the original tire size and the specified inflation pressure for that size - and they do that for the base tire size - and on the other, they seem to think that an additional and separate sticker is the way to handle optional tire sizes, and they are the only ones who seem to think that way.

So in your case, I can NOT say that a P245/75R16 is suitable if the vehicle tire placard only lists the P225/75R16 XL.  I also can NOT say it is unsuitable.  There's a bit more involved than just the tire size.  Rim width for example.

But the first thing to do is look for the other sticker.  It should be nearby the base placard.  If it is not there, that doesn't mean it wasn't there.  (See why I find this odd and confusing?  We can not tell if your vehicle came with P225/75R16's or the other sticker fell off!)  

Luckily, I have a book that summarizes vehicle tire placards - and not only does it list P225/75R16 XL (@ 35 / 41 psi) as the base tire with a P245/75R16 SL (@ 35/35 psi) as an option, it also says some versions came with LT245/75R16 LR C (@ 40/45 psi) - and some with LT265/75R16 LR C (@ 35/40 psi).

I can't tell you what delineates what tires came on what vehicles.  I'll bet that even Chrysler would have a problem even if you gave them your VIN number.  But that is where I would start.