QuestionQUESTION: Recently you answered my question concerning air pressure for my 1997 nissan pickup in which i put 31.10.50 on. the mfg. recommends 26 psi. but that was for 235/75/15 I usually run 35psi, so i put 35psi.in these tires but Walmart put 26psi. in them. Is 35psi. OK?
ANSWER: Dwayne,
If the placard on your truck says the original tire size was P235/75R15 @ 35 psi, then a 31X10.50R1`5LT needs to use ..... drumroll ........ 37 psi.
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QUESTION: No the placecard says 26psi for 235/75/15. i need to know what air pressure for 31.10.50. i have always used 35 psi for truck tires!
AnswerDwayne,
That means my book is wrong. Not only is this not the first time, but in the context of the differing versions of your truck, it didn't quite make sense to me that one version would use 26 psi for the 31X10.50R15LT and 35 psi for the P235/75R15. What you've told me is much more in line.
For practical purposes, a P235/75R15 and a 31X10.50R15LT have similar load / inflation characteristics. So the 26 psi specified on the one version makes sense.
As far as having used 35 psi for truck tires - all tires have a load vs inflation pressure relationship. For example an LT235/85R16 is rated for 3042# at 80 psi - and 80 psi is sometimes specified on certain vehicle's placards. But lighter vehicle may specify a much lower inflation pressure - and it is common for heavy duty pickup trucks to specify much lower pressure for their front tires.
In this case, the truck is a relatively light vehicle and the inflation pressure specification reflects that.
