# Post your Tire Pressures!



## brian v (Dec 25, 2011)

So how hot will those over inflated tires get on that by way to Lordstown Ohoi Get ???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????


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## jblackburn (Apr 14, 2012)

Can't stand to do anymore than 38 on my Firestones or the ride gets too jittery for my liking. There's like 1 well-paved road here and all the rest are full of potholes, patches, and expansion joints. Thank God the Cruze has a great suspension...my old car made noises rather like ka-thump thump thump WHACK BANG thhbbbbbbbbbb CRASH.


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## bodeis (Jan 28, 2012)

Max cold psi is 51 psi. So how is 50 over inflated?


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## iKermit (Dec 13, 2010)

Mine are all set 40 PSI and my MPG didn't go up at all lol... Then again having an SRI makes it tough since i love the freaking sound.


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## H3LLON3ARTH (Dec 16, 2011)

50psi cold

2012 ECO
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## jdubb11 (Mar 14, 2012)

37 on the firestones. had them at 40 but didnt like the ride. cant wait to get rid of these tires. i will probably not rotate them so they go to **** faster


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## Chris2298 (Aug 1, 2012)

Is the 51psi max when cold or the max? I set mine at 48 but they get up to 52psi once they get hot the highway... I assume I'm safe, but reassurance would be awesome...


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## jblackburn (Apr 14, 2012)

Cold. The tires are built to withstand more than that when hot. 


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## blk88verde (Apr 30, 2011)

41 cold


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## 2013Cruze (Aug 4, 2012)

38 PSI cold. 2013 Cruze LTZ RS.


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## Robby (Mar 1, 2013)

45 at ambient.....2012 eco.

Rob


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## 13Cruze (Mar 12, 2013)

Right now 41 cold, but looking at pumping them up a bit more.


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## Aussie (Sep 16, 2012)

36 front 32 rear Cruze CDX diesel, Continental Radials came as OE on car. I always check at night to avoid the sun making tyres hot on one side and giving an uneven reading.


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## ChevyMgr (Oct 27, 2010)

I inflate my vehicles to what the door frame placard states. I believe you roll the dice with over inflated tires. I know many state that they increase their fuel economy, but I don't bite on that philosophy. 

Disadvantages in my opinion are 1) less tire foot print on the road. 2) harsher ride. 3) increase in the possibility of highway speed blow out. 4) irregular tire wear (center wears quicker). 5) increase in possibility of tire damage from pot holes 6) tires heating up quicker, which can cause quicker fatigue and increase blow out possibility.

Of course that's just my opinion. 

If you are on a race or road track with all the required safety equipment. Go for it though!


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## obermd (Mar 3, 2012)

ChevyMgr said:


> I inflate my vehicles to what the door frame placard states. I believe you roll the dice with over inflated tires. I know many state that they increase their fuel economy, but I don't bite on that philosophy.
> 
> Disadvantages in my opinion are 1) less tire foot print on the road. 2) harsher ride. 3) increase in the possibility of highway speed blow out. 4) irregular tire wear (center wears quicker). 5) increase in possibility of tire damage from pot holes 6) tires heating up quicker, which can cause quicker fatigue and increase blow out possibility.
> 
> ...


1) You are correct that there is slightly less footprint on the road, but it's not the width of the footprint - it's the length (direction of travel) that's slightly shorter. According to the NHTSA the stopping distance isn't the same anywhere from door placard to max sidewall.

2) Yes, but for most people and most suspensions, you can boost up to 5 PSI over the door placard without becoming the Princess and the Pea.

3) Blow out is a catastrophic failure of the tire. Tires can safely handle far more PSI than the sidewall limit so the answer is No - tires can easily handle the higher pressure. The answer is also Yes, if you run over something on the road the extra stiffness has a very, very small chance of preventing the tire from flexing over the object. Pay attention to the road and this isn't an issue.

4) The reason you rotate front to back is that even at the door placard pressure, the rear tires will wear more in the middle and the front tires wear more on the shoulders. Front/rear rotation evens these wear patterns out. Cross rotation is to also even out any wear based on alignment problems.

5) See #3 - pot holes and other flaws in the driving surface are road hazards that you need to avoid regardless of tire pressure.

6) Running my ECO MT's tires at 35 PSI resulted in a 10+ PSI increase during hot summer months. When I switched to 45 PSI cold the increase is only 5-6 PSI. The single biggest source of heat and stress on a passenger car tire is sidewall flex as the tire rotates. Higher PSI results in less flex, thus less heat buildup. Less flex also has a side effect of lowering rolling resistance and tread wear.

The door placard pressure is where the manufacturer believes most people will have the maximum comfort, safety, and handling - in that order. As with all engineering design decisions, there are trade-offs. You can improve handling by increasing pressure but at the expense of comfort. In my opinion, better and more predictable handling equates to better safety.

Your thoughts are 100% correct for bias ply tires, but not for radial tires.


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## obermd (Mar 3, 2012)

Now to answer EcoDave:

My ECO MT's tires: 45 PSI cold. Anything above this and the ride gets too harsh for my liking. I have tried as high as 48 PSI.


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## H3LLON3ARTH (Dec 16, 2011)

Mine usually show around 48 psi on all four, I have never seen them over 52 psi driving down the road, i'm also lowered so ride quality is already gone.


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## rb343 (Mar 18, 2013)

Mine showed 47 psi after I got home. 23 mile ride at 80 degrees. I think they are around 42 psi cold. 


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## LS1LOL (Feb 24, 2013)

'13 Eco. The weather has been going from high 20s to mid 70s over the past few weeks (it will change like that in the matter of one day), so the lowest my tires will be is around 48 or so on a cold day upon startup, and the highest I have seen them get on a warm day after driving on the highway is 54. Definitely helps a bit on the mileage...how much, I am not sure. Previously I was running around 43, went up to 51...not too noticeable of a gain, maybe 1 MPG increase. Going from 35-43 was a decent jump though.


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## crazylegs (Apr 25, 2012)

Set at 38 PSI cold...Our back roads are too rough to go higher than that. On a long trip I increase them to 42 PSI cold. Max sidewall is 44 PSI


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## XtremeRevolution (Jan 19, 2012)

ChevyMgr said:


> I inflate my vehicles to what the door frame placard states. I believe you roll the dice with over inflated tires. I know many state that they increase their fuel economy, but I don't bite on that philosophy.
> 
> Disadvantages in my opinion are 1) less tire foot print on the road. 2) harsher ride. 3) increase in the possibility of highway speed blow out. 4) irregular tire wear (center wears quicker). 5) increase in possibility of tire damage from pot holes 6) tires heating up quicker, which can cause quicker fatigue and increase blow out possibility.
> 
> ...


You get used to the ride, but it isnt a concern.

No increased risk of highway blowout. That's flat out false. Blowouts occur as a result of tire degradation and age, not pressure. It takes about 200psi to blow out a tire with air. Even at 50psi, the tires flex a lot over irregular roads. The reduction in sidewall friction and heat will actually extend the compound life of the tire. 

No irregular tire wear. I've recorded 22k miles at 50psi with entirely flat wear. In fact, my shoulders are wearing a bit more.

Tires heat up quicker at lower pressures. Higher pressures reduce sidewall flex and friction.

If you hit a pothole big enough and fast enough to blow out your tire, 10psi would not have made a difference. You would have smashed your rim at lower pressures if you manage to blow out a tire over a pothole. You would also need to see an optometrist.

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## jmurf (Mar 25, 2013)

2013 ECO, 40 psi cold. I went to 45 psi for about a week but the wife complained about the ride quality and she drives it the most...so I compromised and went to 40


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## MD5335 (Oct 16, 2012)

45 cold.


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## brian v (Dec 25, 2011)

That went well ,,, Good Question , Good and precise answers ,
Class dismissed .




BE Cool Stay Cozy and drive safe..............


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## GoldenCruze (Dec 18, 2011)

I set the pressures for the Continentals on my 2LT at 32 psi, which is a couple of pounds over the 30 psi on the door sticker. The tires typically heat up 2 or 3 psi when they get hot.

A harder tire can be less resistant to impact or penetration damage than a tire set to the rated pressure. But I think that it would take a really significant increase in pressure for that to happen.


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## ErikBEggs (Aug 20, 2011)

38-40 PSI cold. 

GM recommends 30 PSI, Tire Max is 44 psi. Go figure.


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## caughron01 (Mar 25, 2013)

I am beginning to think I have a tire pressure issue with the way they filled them. It is supposed to be nitrogen and since I have owned the car now it has 2,000 miles I have seen the tire pressure go from 34-41 PSI..... Is that normal with nitrogen? It just seems like a huge fluctuation in pressure. They were 34 when it was colder here, now that its warmed up they are at 41.


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## obermd (Mar 3, 2012)

caughron01 said:


> I am beginning to think I have a tire pressure issue with the way they filled them. It is supposed to be nitrogen and since I have owned the car now it has 2,000 miles I have seen the tire pressure go from 34-41 PSI..... Is that normal with nitrogen? It just seems like a huge fluctuation in pressure. They were 34 when it was colder here, now that its warmed up they are at 41.


Welcome to one of the myths about nitrogen. It's a gas and when you consider normal air is 78% nitrogen and must respond to heat the same way as any other gas, the "it doesn't change pressure" is obviously a myth.


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## LS1LOL (Feb 24, 2013)

obermd said:


> Welcome to one of the myths about nitrogen. It's a gas and when you consider normal air is 78% nitrogen and must respond to heat the same way as any other gas, the "it doesn't change pressure" is obviously a myth.


Did you actually check the coefficient of thermal expansion? If it is a good amount higher than that of "air" than I could see that change easily happening due to weather conditions. As mentioned in my post before, I have had my tires read as low as 47-48 on a cold morning and as high as 54 on the highway...


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## arsmitty86 (Feb 26, 2013)

I had mine at 35PSI cold and then the stealership reset them to 32 on my last oil change. I've noticed the ride is better again and although the handling isn't as immediate theres more grip at 32 (which makes sense). I might just leave it. Makes maybe a mile a gallon or two difference and I like the ride/handling characteristics better at 32.


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## cchall (Feb 9, 2013)

2011 LT with Michelin Energy Saver A/S at 45psi. I like this tire a lot more than the old Firestone that came on it


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## obermd (Mar 3, 2012)

LS1LOL said:


> Did you actually check the coefficient of thermal expansion? If it is a good amount higher than that of "air" than I could see that change easily happening due to weather conditions. As mentioned in my post before, I have had my tires read as low as 47-48 on a cold morning and as high as 54 on the highway...


The Ideal gas law - Wikipedia, the free encyclopedia for gas expansion has to term for coefficient of expansion. The only variables are are temperature, volume, and initial pressure. Since the volume and initial pressure are constant in a car tire, the only thing that can cause changes in the resultant pressure is temperature.


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## LS1LOL (Feb 24, 2013)

obermd said:


> The Ideal gas law - Wikipedia, the free encyclopedia for gas expansion has to term for coefficient of expansion. The only variables are are temperature, volume, and initial pressure. Since the volume and initial pressure are constant in a car tire, the only thing that can cause changes in the resultant pressure is temperature.


Nitrogen is not an ideal gas, therefore the combined gas law may not the proper formula to use.

Ideal gas - Wikipedia, the free encyclopedia

I would have to look at the temperature/pressure range that Nitrogen has "ideal gas-like characteristics," but my Thermo book is at work and I am off the rest of the week.


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## Chris2298 (Aug 1, 2012)

I've heard the salesmen tell me why nitrogen is better but I've never researched it.. Thanks to our friends at Google, becoming an expert takes all of about ten minutes.. From what I'm seeing, the biggest benefit of the nitrogen is the lack of moisture.. I was going to fork over the 40+ dollars for the nitrogen fill... Not now...


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## DMC (Oct 22, 2012)

38 cold. I drive through a couple of construction zones several times a week, any higher and I can't stand the ride. The slight increase in MPG was not worth the decrease in ride quality to me.


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