Tires: 1993 GMC Suburban 4WD Tire Pressures, lane highways, suburban 4x4

Question
QUESTION: Hi.  The tire placard fixed to the inside of the left front door is printed in invisible ink.  Is there some way for me to get the info that is "printed" on this placard?  My issue is unstable handling at highway speeds.  The rig has Bridgestone, V-Steel Rib 265, LT245/75R16, Load Range E, M+S, Radial Steel Belt tires on it that have less than 10,000 miles.  My dealer recently returned the rig from a routine service noting 35psi in all four tires.  I've heard about 45psi in all four tires from the local Buick dealer.  I've also heard that the tire pressure may be recommended to be staggered i.e. 40psi front and 65psi rear.  This rig drifts from "line to line", on the edge of control when being driven on 2-lane highways, especially with strong cross-winds.  I've got a front-end inspection scheduled next week with a mechanic other than my tire dealer.  Any help or suggestions?  Family safety rules here.  Thank you.  Lynn Engle.

ANSWER: Lynn,

According to Tire Guides, a 1993 GMC Suburban 4X4 K1500 either came with LT225/75R16 LR D's inflated to 40 psi front / 65 psi rear

- OR -

LT245/75R16 LR C's inflated to 45 psi front and rear

- OR -

if it was a K2500 LT245/75R16 LR E's inflated to 45 psi front / 80 psi rear.


So clearly, the 35 psi value is wrong.

I would suggest you spend a lot of time trying to read the placard given the above possibilities.  If you still can not make some sense of this, ask GM for help.

But I'm going to suggest that there is some other problem, rather than tires.  Nevertheless, you need to confirm what the pressure is supposed to be.

---------- FOLLOW-UP ----------

QUESTION: Barry.  My Suburban is a half-ton, the K1500 version.  I'm going to check with my tire dealer and see what it will take to get a "spec'd" set of tires on it.  Then, I'm going to my full service filling station and see about tires there.  This rig is in real good shape and has lots of miles left.  It isn't worth anything to anyone but us.  It is paid for.  Thanks for your help.  Really appreciate the prompt reply.  Be safe.  Lynn.

Answer
Lynn,

As you saw in my reply, the K1500 had both LT245/75R16's and LT225/75R16's, so the tire shop is not going to know what is "spec" - but GM might be able to decode the VIN enough to tell you what the original tire size is.

But you probably can save yourself a lot of time if you really work at trying to read the tire placard.  Even a little bit of printing might be able to shed enough light on the subject so you can fill in the rest of the blanks.