Tire Pressure - What should it be..really?

[jshaf]

when I put air in I usually put it to 38 and let it gradually go down to 33-35 then fill them again, usualy takes a few months. I don't sweat it too much just as long as it is about 33-34 and there all about the same!

[biggvan]

I set my 20 inch pirellis at 45 pounds cold. I want to decrease rolling resistance a bit since I do alot of highway driving during the week( got car last may, have 79,800 miles on it now :-( ) and during the weekends i make it a point to never waste a good corner with halfhearted driving. I dont recall how long the rear tires lasted, they did go first due to nail damage...but the front pirellis lasted for 57K miles of even wear. I offer that merely as anecdotal evidence and my personal preference. I wont argue against anyone who maintains that the sticker is always right.

[jsherm007]

Checked mine today (yesterday got two new fromt tires unde warranty @ 917 miles total on car!) and all tires were at or just below 30psi from dealer. I bumped it up to 38 all the way around.

I know on my C5 vette if I over inflate the DIC let's you know... Max for vette to not get warning was 42psi. So I did 38 so when they warm up there is no DIC warning. Max on those tires is 51.

[Brianskeet]

It appears a great many are as crazy about tire pressure as I am. Here is my solution. the dash is close to the truth, but this thing is exactly right all the time. I swapped tires to 275's and 305's. Routinely run 37 lbs to keep my wider tires from cupping and the dash always sees it as a bit higher. I only use the dash to monitor the change as the tires warm up.

[n116ebo]

I always set mine at 38 cold, every month or so I have to bump them back to 38.

[KING_DJ]

Leaving thread to much math!

[Rudy@Tirerack]

Follow the door placard. Max is just that Max not what you should run.

[Bobaloo]

I air at 36 lbs cold and use an Aircomp 3" 270* sweep tire gauge. It is really accurate and easy to air at 1/2 lb setings. When I go from 5,000 feet MSL here in CO mountains to a state less than 1000 feet I'll inflate to 38 pounds ahead of time otherwise I'll be low when I get to the destination. I have almost 20K on my factory Pirellis and they look like I'll get another 5K before changing. Then I'm going with Continnental Extreme DWS all season tires warranteed for 50K miles. Those tires I can rotate side to side.

[blackswan]

While the door sticker says 36 pounds for each tire, it might not be the optimal for balance (perhaps unless the car is bone stock, and even then perhaps tire tread depth/compound might play a role). Here's some old school but still relevant information (even has an IROC ):

[dklowrider]

Originally Posted by blackswan

While the door sticker says 36 pounds for each tire, it might not be the optimal for balance (perhaps unless the car is bone stock, and even then perhaps tire tread depth/compound might play a role). Here's some old school but still relevant information (even has an IROC ):

That is some pretty cool stuff. I know for optimum traction in a competition setting that each pound of air is critical, but on a practicality scale I give this a score of 2. One thing you could do fairly easy is checking the sidewall roll over. The easiest advice was the art of listening to your tires.

[redleader]

well, I start the morning at 33psi on the driveway and within about 2 miles it's up to 38psi all round ... OK?

P.S. no ... my driveway is not 2 miles long :-)

[Rock-It Man]

Originally Posted by mikeyroche

Not really BS at all. We use it at work all the time on the Aircraft. Nitrogen is far more superior then air

Only because the nitrogen you use is free of water. Dried out air would work just as well, since the gas law applies to all the gasses.

[G8One2]

Sorry to bring up an old thread, but I see some confusion here. The manufacturer sets the tire pressure based off of gross vehicle weight. Which is a bit higher than curb weight. There's a difference between curb weight and GVW.

The gross vehicle weight rating (GVWR), or gross vehicle mass (GVM), is the maximum operating weight/mass of a vehicle as specified by the manufacturer[6] including the vehicle's chassis, body, engine, engine fluids, fuel, accessories, driver, passengers and cargo but excluding that of any trailers.[7] The term is used for motor vehicles and trains.

The weight of a vehicle is influenced by passengers, cargo, even fuel level, so a number of terms are used to express the weight of a vehicle in a designated state. Gross combined weight rating (GCWR) refers to the total mass of a vehicle including all trailers. GVWR and GCWR are used to specify weight limitations and restrictions. Gross trailer weight rating specifies the maximum weight of a trailer and the gross axle weight rating specifies the maximum weight on any particular axle.

Curb weight (American English) or kerb weight (British English) is the total mass of a vehicle with standard equipment and all necessary operating consumables such as motor oil, transmission oil, brake fluid, coolant, air conditioning refrigerant, and sometimes a full tank of fuel, while not loaded with either passengers or cargo. The gross vehicle weight is larger and includes the maximum payload of passengers and cargo.[1]

This definition may differ from definitions used by governmental regulatory agencies or other organizations. For example, many European Union manufacturers include the weight of a 75-kilogram (165 lb) driver and luggage to follow European Directive 95/48/EC.[2] Organizations may also define curb weight with fixed levels of fuel and other variables to equalize the value for the comparison of different vehicles.

The United States Environmental Protection Agency regulations define curb weight as follows: Curb weight means the actual or the manufacturer's estimated weight of the vehicle in operational status with all standard equipment, and weight of fuel at nominal tank capacity, and the weight of optional equipment computed in accordance with §86.1832–01; incomplete light-duty trucks shall have the curb weight specified by the manufacturer.[3]

For reference https://en.wikipedia.org/wiki/Vehicl..._weight_rating

So with all of that said, the manufacturer set the tire pressure based off GVW. So unless your running around in a fully loaded vehicle, pushing the maximum GVW, setting tire pressure to what the door sticker says may cause them to be slightly over inflated. I tend to go 2-3 lbs less than what the door sticker says and pay attention to where the tire is wearing when I swap them or rotate them. Doing this should give you a better idea of what tire pressure to actually run on your vehicles. I currently run 34psi cold on my 2014 2SS and see even wear across the treads.

[AlanRubin]

I run what the door jam sticker says, up front, which is 35PSI.

When I run 35 in the rear tires, they wear down the center. SO, I run 33 in back.

That PSI is also with the wheels OFF the ground.