Pressure

[Oil Changer]

Goal: Best fuel economy.

Tires say 44 psi max.

Door jam sticker says 30 psi front and rear.

That's a 14 psi spread.

Tires have 32 psi in them now. Bought the car in December so they probably were set at 30 psi and the warmer temperatures were good for another 2 psi.

What should I do?

Run them up to 44 psi?

Split the difference and set them at 37 psi?

Other ideas?

 

[abycat]

The door jam sticker is for the same size and type of tire that came with the car. If you have the same tires use the door sticker. You can go a couple up or down from that but stay close.

If you had totally different tires you need to find the load rating and max pressure on them. If they are the same as the origional tires put them the same as the door sticker.

If they are not the same load rating and psi you need to figure out what to set them at for your application.

Dont ever set any tire to the max psi. cold pressure will be quite alot less than hot and then the psi is waay more than max and that is not cool.

 

[ahoier]

Set them to 44 PSI MAX (first thing in the morning, before the car is driven..... - or late at night after the car has sat for 3+ hours) - if they feel too "hard", then lower them to 42, 40, etc....til you find that "sweet spot"....

The higher the pressure, the more "responsive" the tires will be as you go into turns, stop, etc......you may also feel that the wheels ride like a "rock" lol.....i.e.: you'll feel every bump and pebble in the road

The lower the pressure you go, the more "comfort" you will have while driving......the lower the pressure, the more 'flex' the sidewall will have as well.

Obviously, for best fuel economy, you'll attain that at 44 PSI.....but you don't want to sacrifice your handling either to save a couple pennies

And a side note: the early morning, or late night PSI check, is for the "Max COLD" PSI.....cold being defined as, not being driven for 3 hours.....

Monthly, I check my PSI in all my tires, and I typically will check the pressure twice, 2 days back to back, just to rule out any variance in pressure.....call me redundant....but there was one time it was a little bit "off" the next morning.....


And never "let out" air, from a "warm" tire.....as the tires are driven, the air expands, so they will "read" a higher PSI after say, a long road trip

Now that doesn't mean don't check your tire pressure while on a road trip....it just means do not REMOVE air, while on a road trip, if your tires are reading "over" the Max PSI mark.....since the "Max PSI" number is for "cold" tires, having not been driven for 3 hours........or driven less than 1 mile I believe (to give you some leeway to get to an air pump).


Another reason why I say to check the tire PSI back to back, 2 days

The air gauges on the gas station pumps are usually NEVER right, since they get dragged, dropped, ran over, etc......


[censored], even my 250 PSI portable 12v tire inflator was "off" by about 10 psi yesterday when I checked my PSI......the inflator noted 30 PSI, and my tire gauge said 20........tempted to return it.....but it does fill the tires Which was what I wanted hehehe.....I got loads of tire gauges heh.

 

[azjake]

My door jam says 32, but I run them at 35psi since I feel it improves handling over 32. Try different settings to see what feels/handles best for you, but I do think 44psi might be too bone jarring going over bumps or rough roads.

 

[Oil Changer]

Factory tires. New CR-V AWD.

The 14 psi difference (I think) is alot. I figured the factory tires would be close to what the sticker suggests.

I think I will take readings when the tire is hot, and adjust the cold psi until I get 44 psi hot.

 

[HerrStig]

44 is a fully loaded pressure. Run 'em at 44 otherwise and you wear your suspension, AND wear the center of the tire. There is a sweet spot, but it must take into consideration the roads in your area and the load you carry in the car.

 

[Bgallagher]

What you might gain in a slight increase in performance and gas mileage (SLIGHT) you will drastically increase tire wear. The tire manufacturer might have a max for the tire but the car manufacturer made the car to include the tires. Go with the sticker on the side. a LB or two wont hurt it but dont jump it.

 

[Astro14]

Sigh...another "hyperinflation" story?

You should start with the door jamb/OM pressure, and while you can go up to the sidewall pressure, if you do, you're likely to sacrifice tire life, ride, suspension life...it's a specious goal...and the cost of replacing tires sooner will more than cancel out the fuel savings...

I might go as much as 4 PSI over door jamb, that's often recommended for high speed driving, and it will keep you well below the sidewall pressure without increasing center tread wear or harming ride and other handling characteristics...

It will take several thousand miles to know what improvement you've made in mileage, and what increased wear you may be causing. As an example, I ran my 235/45R17 tires on the T5 at 42-44 PSI...and the center tread wore out before the edges...now, I run at 38 PSI (OM pressure for high speed, well below the sidewall max of 50 something...).

 

[A_Harman]

^ What Astro14 said. The owner's manual gives the proper inflation pressure for your car with the original tires. Overinflating will save fuel, but the center of the tire will wear out sooner, erasing any savings because you sacrifice life of your tires.

 

[Chris142]

always check tires cold. never hot as hot tire pressure is irrelevent. running overinflated tires may get you slightly better mpg but any savings will be cancelled out by the accelerated tire wear

 

[JHZR2]

Its not a lot. It is really a stupified pressure chart.


Most of my cars have a main reading for light loads and slow use, and then a rating for if the car is loaded, and another addition if the car is to be used at high speeds.

So there actually is a range of pressure that you might want to operate at. Hypermilers will say that they can go to sidewall pressure or higher, and not see incorrect wear. That's likely due to their driving style...

To me, I would go as high as possible without getting an inconsistent contact patch, or a pressure over the sidewall rating. I saw an article once on how to best do it. Essentially you need some white dust (chalk fine powder in a thin coat on the ground) to roll through and then look at the contact patch/what was picked up on your tires.

 

[Kuato]

I always set my pressures to the tire's max to start, and check wear after 5k miles. I've found that factory pressure will cause wear on the outside of the tires - it's obviously set for comfort rather than tire longevity. In general higher pressure will get better mpg as there is less rolling resistance.

 

[SrDriver]

Check the following web site regarding tire pressure.

Link to Web site

Notice the part about inflation pressure.

 

[moto94536]

do whatever you want as long as it is not below 30 or over 40.. my car call for 29.. I put 36 psi all around.

 

[moto94536]

one more thing a few member said when they run recommend 32 psi on their honda pilot, their tires doesn't last long..

 

[CapriRacer]

Tires are standardized, so it doesn't matter who makes the tire. If the tire size is that same as listed on the vehicle tire placard, then that is what the vehicle manufacturer is recommending.

EXCEPTION: There are P type tires and there are LT type tires - and these are different kinds of tires. If your vehicle came with P type tires and you install LT type tires (I would not recommend the reverse!!), then the pressure in the LT tires needs to be about 15 psi higher in order to carry the same load.

Side note: Tire manufacturers will always defer to the vehicle manufacturer on inflation pressure.

2nd side note: The pressure listed on the sidewall of a tire is NOT a recommendation. Usually it is listed as a MAXIMUM.

As far as using more pressure than the vehicle manufacturer specifies: Since the tire manufacturers work hand in hand with the vehicle manufactuirers, there is very little data concerning the affects high inflation pressures have on various tire properties. To try to fill in this gap, over the years I have been documenting reports from folks who use high inflation pressures - and while these things are 100%, there enough reports to be able to state that using high inflation pressures:

* Tends to wear the centers of the tread.
* Tends to cause wet traction issues.
* Tends to cause rough ride - even to the point where the vehicle becomes difficult to control.
* Tends to cause groove wander (tramlining)
* Tends to make the tire more prone to punctures and impact damage.
* Tends to improve steering response.
* Tends to improve fuel economy.

 

[SteveSRT8]

Thus the only thing a tire user needs to determine is whether the last two incremental improvements are worth the 5 previous points that are profoundly negative, IMO.

 

[Boss302fan]

I have found that on most of my vehicles, that 35-36 PSI has worked best for me... That is usually 3-5 psi higher then what the door sticker states.

 

[JOD]

Originally Posted By: SteveSRT8
Thus the only thing a tire user needs to determine is whether the last two incremental improvements are worth the 5 previous points that are profoundly negative, IMO.


Well, the other thing the user needs to determine is "where is the break point at which those things start happening". For me, it's quite a bit higher than the door pressure (but lower than the max pressure). I was actually getting accelerated wear on the edges of the tires when running the door pressure. I've ended up settling on 40F/38R on my vehicle (door is 32, max is 44). It's a good compromise for all of the parameters listed above. Mostly, I'll trade steering response for a slightly harsher ride, in particular since the Primacy MXV's feel too soft to me otherwise. Wet traction is still good (I should know...).

The door pressure is always a compromise. I think your best best is too experiment a bit (within the max pressure limits) while checking how your tires are wearing and how the car handles.

 

[SteveSRT8]

^^^This is a reflection of what I always talk about on here: We're all different, so no one thing fits all our needs.

I also rarely run the exact pressure on the door sticker, but I also rarely have the same tire or loading. You have to tune it as you say...