QuestionI own a 1994 Chevy C2500 ext cab Truck. The label on the door jam says the tires should be LT245/75R16E with a tire pressure of 40 psi for the front and 60 psi for the rear. I'm shopping for new tires and would like to get P265/75R16 tires. I like the look and the slight additional ground clearance of the 265/75 tires. I have used Bridgestone Dueler A/T Revo LT265/75R16 tires on this truck for many years with no problems. I'm considering the P-metric tires only because they tend to be less expensive than the LT tires. I never carry heavy loads such as a camper with this truck and only infrequently carry light to medium loads, so I'm wondering if I really need the LT series tires.
AnswerTony,
First, the original rims on your truck are 6.5" wide. That means the widest tire you can put on the truck without changing rims is .... LT245/75R16. An LT265/75R16 requires a minimum of a 7" wide rim.
Second, I am not a fan of exchanging LT metric tire for P metric tires - and vice versa.
In order demonstrate this, I tried to put some numbers together - and the one question I couldn't answer - and get numbers I could believe were reasonable - was: What is the payload of the truck? What I was intending to do was to show that a P245/75R16 did not have enough load carrying capacity, even if we assumed a moderate payload. The problem I kept confronting was that published values for the payload seemed incredibly high - too high for the 60 psi load carrying capacity an LT245/75R16.
So I've decided to show it to you this way:
A P245/75R16 has a published capacity of 2271#. If we deduct the 10% that is used when P metric tires are used in a Light Truck application, the usable capacity of the tire is 2065 #.
An LT245/75R16 carries that load at 47 psi - which means the difference to 60 psi is a reduction of 720# payload - which is a huge reduction.
If your owners manual has the payload capacity, I could do a better job of explaining this, but without that, this is the best way I know how.
