Tires: tire ratings, stock rims, overload springs


Question
I have to replace the tires on my 1996 dodge heavy duty 1/2 ton work
van .When put on the scales and weighed with a normal load it will weigh
around 6875. lbs On the front of the vehicle are cooper discover ht
p235/75r15 tires on the rear of the vehicle are goodyear lt235/75r15 tires
with load range c. My question is how important is the load range
designation? This vehicle does carry more weight than it should and have
installed overload springs on , and realize proper tire size is  important. Any
imformation you could provide would be very much apreciated. Thank you in
advance for any  

Answer
David,

Let me start out by saying, it has been my experience that when a truck gets overloaded, people spend a lot of time and money trying deal with the problems overloading creates, when buying a truck that is designed for that weight would not need to be re-engineered.

How important is load range?  It's only important if you don't care about tire failures and the possibility that the driver might be killed.

But you have a problem.  This vehicle should have P235/75R15 XL.  Unfortunately, you need to go to 16" rims to get significant increases in load carrying capacity.

You could use an LT235/75R15 Load Range E, but that requires 80 psi.  I don't think the stock rims are adequate for that kind of pressure.

See what I mean about re-engineering the vehicle for overload?

So my advice would be to either buy a bigger truck or avoid these heavy loads.