Stock tire pressure

[LouF]

It seems I go through this every time I switch to winter tires (and back) - what is the tire air pressure consensus?

I am using (stock sized) P265/75R16 tires on my '93 K1500 Silverado p/u. The door tag specifies 40/35 (front/rear, p.s.i.) for LT, mine are actually P. I won't be carrying or towing anything (normally) - just regular commuter driving.

The intent is to maintain even tread wear on these snow tires (Firestone Winterforce). Thanks.


In case anyone is interested (these are a bit older model now), these tires have been great (that's why I want to keep them as best as possible).

 

[Nad_Yvalhosert]

Spray a section of tread with water. Drive far enough to leave a watermark on the ground. Air up or down until you get a full tread width wet patch.

Next, keep track over the weeks to see if you're losing rubber from the edge or center. Adjust as necessary.

I view the door sticker as a place to begin negotiations. My best suggestion as a starting point is halfway between door sticker and sidewall max spec.

 

[F4U-1A]

Tire PSI it set my the manufacturer for maximum performance safety and handling. I have had both LT and P, winters and summers. Makes no difference. 40 seems high, but I only have a 96 C1500, (32,35).

 

[454cid]

I am using (stock sized) P275/75R16 tires

275??? Is that a typo?

'93 K1500 Silverado p/u. The door tag specifies 40/35 (front/rear, p.s.i.) for LT, mine are actually P. I won't be carrying or towing anything (normally) - just regular commuter driving.

I'd probably just go with that unless that its higher than your passenger tires are rated for. I run lower than factory on my truck, but I've got a 1-ton and the door tag reads 80psi, but I don't normally tow anything.

 

[F4U-1A]

275mm does sound very wide. And 80PSI for a 1 ton? Get a blow out, would sound like a shot gun. LOL

 

[Erik the Awful]

Also, remember that your pressure rises 1 psi for every 10 degrees temperature. Take your air pressure readings with the tires hot - like right after you get off the highway.

When I autocross, I run about 44/40 psi front and rear. When hot my tires are about 150*. That's a 10 psi difference from a 50* day.

Of course, if you run 95+% nitrogen, the pressure change is far less significant.

 

[stutaeng]

275mm does sound very wide. And 80PSI for a 1 ton? Get a blow out, would sound like a shot gun. LOL

Yeah, the front/rear is 50/80 psi, respectively for 3500 SRW trucks. Not sure on 2500 or DRW, probably the same, as well as 2500 suburbans. I "sometimes" remember to air my tires on my truck if I'm running a load on the bed of my truck, but admittedly, I sometimes forget. Can't remember if I can perceive a difference. Dunno.

All LT tires on my trucks though, even my 1500 that came with P-series tires. I think that one just gets 35 psi all around. I think that's spec or close enough.

 

[Coveman]

40/35 for LT tires sounds low to me, those values actually look right for Ps. There are several good sites to help you find the proper psi, here’s an example from goodyear: http://www.goodyear.com/rv/pdf/rv_inflation.pdf

another route is to use a little math:
TIRE INFLATION EQUATION:

Tire Max Weight rating/ Max Tire Pressure = Load Capacity Pounds per PSI
Example:
At 80psi, a 265/75R16 tire will carry 3,085 pounds of load.
At 60 psi, the tire's load carrying capacity is reduced to 2,314 pounds per tire.
If you run 65 psi , the capacity is now 2,507 per tire.
Tire Weight Rating / Tire Pressure = Load Capacity Pounds per PSI

Here is this formula using a 265/75R16 E with 60 psi in the tire;
3,085 / 80 psi = 38.57 pounds of carrying capacity per PSI.
38.57lb X 60psi = 2,314 load carrying capacity

The manufacturer’s placard generally is for minimum safe pressure in the tires originally equipped. The tire’s rating and the load you are carrying should be more accurate given so many different tire manufactures and model configurations.

 

[LouF]

Thanks all.

Uh hem...yes, "275" was a typo . I corrected the post, the tires are 265.

I now also recall the tread chalk line test after reading the tread water method.

It is interesting to see the difference between C and K models. I'd bet there is some comfort attention in that recommendation.

I'm a little cautious about hot tire readings - I though it was always at cold, unless you mean watching for over-inflation doing the half-way between door placard and maximum tire pressure "negotiations".



I forgot what a can of worms this gets to, but the refresher is good.


Going to the Firestone webpage, it told me 50/50 psi. (not doing that). I guess I'll go per the placard, although this seems to anticipate a load. I might drop 2 psi. The other reason to pore over this is the tires are too warm this week to have them set up for the cold days.


THANKS everyone!


Also, I forgot to check the owner's manual. What I additionally learned, I'll pass on:

Special Tire Attention: If you have 16" tires, and:
-If you'll be driving for very long times of 66-75 mph, inflate tires 10 psi more than recommended cold inflation pressure.
-If you'll be driving for very long times of 76-85 mph, inflate tires 10 psi more than recommended cold inflation pressure, and you must also reduce axle load by 10%. Do not drive above 85 mph even if it is legal.
-Inflation pressure should never exceed 10 psi above the inflation specified for the maximum load of the tire.

 

[F4U-1A]

40/35 for LT tires sounds low to me, those values actually look right for Ps. There are several good sites to help you find the proper psi, here’s an example from goodyear: http://www.goodyear.com/rv/pdf/rv_inflation.pdf

another route is to use a little math:
TIRE INFLATION EQUATION:

Tire Max Weight rating/ Max Tire Pressure = Load Capacity Pounds per PSI
Example:
At 80psi, a 265/75R16 tire will carry 3,085 pounds of load.
At 60 psi, the tire's load carrying capacity is reduced to 2,314 pounds per tire.
If you run 65 psi , the capacity is now 2,507 per tire.
Tire Weight Rating / Tire Pressure = Load Capacity Pounds per PSI

Here is this formula using a 265/75R16 E with 60 psi in the tire;
3,085 / 80 psi = 38.57 pounds of carrying capacity per PSI.
38.57lb X 60psi = 2,314 load carrying capacity

The manufacturer’s placard generally is for minimum safe pressure in the tires originally equipped. The tire’s rating and the load you are carrying should be more accurate given so many different tire manufactures and model configurations.

I love math.

You must be registered for see images attach

You must be registered for see images attach