tire pressure

[deaf electrician]

Put snow tires on the wifes 2003 denali wild country TXR's 265 70R17. The handling now seems mushy and the tires look a little low on pressure. Checked the pressure and all were 35 to 36 psi.

 

Manufacturer recommends 30psi for 17 in stock rims. I was wondering what tire pressure everyone was using.

 

I had these same tires on our 96 suburban set at about 45 to 50 psi with now problems but manufacturer recommended 50psi. Don't know why such a low pressure on the denali.

[Machine]

Are you referring to the Denali recommendation or the tire mfg recommendation?

 

 

We just bought a Suburban Z71 and the door indicated 30 psi for the factory 265 /70R/17's. When the SUV came out of prep at the dealer the tires had 35 psi in them. I'm keeping them at 36 and will monitor the wear. 30 psi just seems really low for a mild AT tire, and you can feel it in the ride.

[deaf electrician]

I'm referring to the dealers recomendations. Our old suburban listed 50psi and the new 2003 denali lists 30psi. I have the tires set at 35psi but still seem too mushy. I was thinking of increasing the pressure to maybe 40-45psi, but I don't want to void warranty or cause safety issues.

[Machine]

I believe that the GM recomendation is for the factory tires.. Your new snow tires may have a different rating. Look at the sidewall of the tire. It may say different. My 2500HD has aftermarket 305’s on it and I run it according to the tire sidewall minus a few pounds for comfort.

[Ben]

Most dealers assume they are "P" rated tires on any 1500 and correct that most P rated tires max out at 35psi, some might go to 40-44psi.

 

LT tires are next higher class tire and they can range from 50psi to 80psi.

 

Now that Dodge and GM have trucks with LT265/70R17 tires, you'll find some dealers that will just put in 35 psi thinking it's old P rated, as 70 series was not available in LT tires till the H2 came with LT 70's.

 

Do the simple math and figure out what pressure is right for your axle.

 

Take the tire's max weight rating and max pressure rating on graph paper (linear, NOT log). Then draw a line from that dot to zero. Then fill in the rest of the lines between those two points. Half way would be half psi or weight in lbs.

 

Then find your GAWR and divide by two to get each tires potential loading. Add some safety factor, say 10%. Now find that weight in lbs on the chart, the coressponding psi is the min pressure stone cold.

 

Here's one I made up for my Suburban's LT265/75R16E's

 

[deaf electrician]

I just called the dealer and they said the pressure listed on the door (30psi) was as stated in last post for the factory passenger tires and that with truck tires which I now have on, I should use the rating on the sidewall. Thanks for the help guys.

[Shaners]

I just called the dealer and they said the pressure listed on the door (30psi) was as stated in last post for the factory passenger tires and that with truck tires which I now have on, I should use the rating on the sidewall. Thanks for the help guys.

Keep in mind that the rating on the sidewall is most likely "MAX" tire pressure. Inflated to those numbers the tires could give a harsh ride and uneven wear.

 

For example... the 265/75/16 load range "E" tires on my truck are rated for 80 psi. I run them at 50 psi and the ride and wear is very good.

 

Depending on the max pressure rating on the sidewall (load range), then you may want to run them more in the upper limits.

 

Also, there is a MAX pressure rating on aluminum rims. I don't know what it would be on your truck, but somewhere (most likely on the inside) the rim should be stamped with maximum pressure ratings.