QuestionQUESTION: I have a F-350 4x4 supercab with LT265/70R/16 tires the only pressure specs I can find for this truck is max load pressures.
80psi.now this is two high for everyday driving and tires wear in overinflated pattern.They are listed as 10 ply what should the pressure be for this type of tire?I at the moment have winter snow tires on it.so at what pressure should I start?
ANSWER: William,
Here's my usual write up on pressure:
On every vehicle sold in the US, there is a sticker – commonly called the tire placard - that lists the original tire size and the proper pressure for that size. The placard is usually located on a doorpost or in the glove box – but sometimes it is located in the trunk or on the fuel filler door.
BTW, it doesn't matter who makes the tire or what pressure is listed on the tire's sidewall, if the tire size is the same as the placard, then the pressure listed on placard is also appropriate.
One word of caution: Some trucks use tires with the letters "LT" in front of the tire size - and some trucks use tires with the letter "P" in front of the tire size - and some trucks use tires with the letter "C" after the tire size. You should not use "P"'s in place of "LT"'s and vice versa.
You should be sure the pressure on the sidewall equals or exceeds that pressure on the placard. If you do this the issue about the letter "C" in the sidewall will take care of itself (which is not true with "LT"'s vs "P"'s.)
If you are using a tire size that is different than what is listed on the placard, then the pressure has to be recalculated. The calculation is not difficult, but it requires tire load tables which are not allowed to be published in the Internet because of copyright laws. However, I have a copy and would be glad to do the calculation, but the starting point is the vehicle placard: Tire size and inflation pressure. I will also need to know the new tire size.
So what does your vehicles' tire placard say? Is it different that what you have on the vehicle now?
---------- FOLLOW-UP ----------
QUESTION: thanks for the reply.The tires on the placard are LT265/75R16 and that is what is on the tire that is on the truck at the moment.the placard gives 2 pressures one is 55 and the max load is 80psi.I guess that is the answer I was looking for,however I found the difference between the two a little excessive hence my question.If this is what they should be at I am good to go unless the wear shows something else I guess Thanks
AnswerWilliam,
In your first post, you said you had LT265/70R16's on the truck, then in your second post you said the tires are LT265/75R16's, which is what the vehicle placard says. (70 vs 75) So be sure you have this correct, because you will get a different answer for each.
