# What's the right tire pressure?



## obermd (Mar 3, 2012)

The correct tire pressure is anywhere from the door placard to the max sidewall pressure printed on the tires themselves. Measure the pressure at the median temperature for the time of year. This means that in the winter it actually takes a little more air to maintain the same pressure. The actual pressure you run will depend on how it feels to you. Higher pressure results in less sidewall flex, which means more feel of the road is transferred to the passenger compartment and steering. This results in a "harsher" and possibley slightly noisier ride but improved cornering performance since the tires won't bend over to the sidewall as much during hard lateral motion. Also, there have been reports that running at max sidewall along with regular rotation, balancing, and alignment is the way to get the most mileage out of a set of tires.

Modern radial tires shouldn't buldge in the middle of the tread when running at max sidewall pressure. Also, they shouldn't cup in the middle of the tread when running at the door placard's pressure. If they cup at the door placard's pressure, put more air in them as the door placard pressure is to low for the load the tire is handling (Ford Explorer rollovers and blowouts). If you decide to run at max sidewall and they buldge, you have a defective tire. If you take a lot of hard corners watch the outer edge of the tread, especially on the front tires. If it's wearing out faster than the rest of the tread then add more air up to the max sidewall pressure.


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## scha7530 (Apr 15, 2012)

I've been running 35 cold. Seems to be wearing well (only 3400 mi), and autocrossed it twice with no tire roll issues. The ride quality is still pretty decent too. I don't think I would run them at 30, that's for sure.


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## XtremeRevolution (Jan 19, 2012)

70AARCUDA said:


> ...one of the *BEST* *worded* answers I've seen posted on this subject in a long time!


Agreed.

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## GoldenCruze (Dec 18, 2011)

> The correct tire pressure is anywhere from the door placard to the max sidewall pressure printed on the tires themselves.


Good answer, but I am not in complete agreement with it. I do agree that it is the safe range of tire pressures without the tires being under inflated, which is the most dangerous range of pressures that you can have. Under inflated tires can fail rapidly.

I have the same wheels and tires as the OP. The car left the dealers lot with 33psi all around. After a rotation at the dealership earlier this month, they increased the pressures to 34psi rear and 35psi front. The car seems to skip sideways slightly on a hard, bumpy turn, or break traction more easily in a turn. Handling problems. I'm going to try lowering the pressures to the door sticker rating and see how that goes.

Truly, the best answer is to follow the door sticker. By doing so, you get the *best combination* of ride, handling, safety, and mileage. Sure, changing the pressures can increase performance in one or more of those areas, but it can be at the sacrifice of one or more of the other factors. It'll be up to you to decide what you like best.


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## BladeOfAnduril (Apr 27, 2012)

I'm running mine at 45-46 psi cold. I have not noticed any loss of traction or braking ability. I plan to increase them to 50 psi. 

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## obermd (Mar 3, 2012)

GoldenCruze said:


> Good answer, but I am not in complete agreement with it. I do agree that it is the safe range of tire pressures without the tires being under inflated, which is the most dangerous range of pressures that you can have. Under inflated tires can fail rapidly.
> 
> I have the same wheels and tires as the OP. The car left the dealers lot with 33psi all around. After a rotation at the dealership earlier this month, they increased the pressures to 34psi rear and 35psi front. The car seems to skip sideways slightly on a hard, bumpy turn, or break traction more easily in a turn. Handling problems. I'm going to try lowering the pressures to the door sticker rating and see how that goes.
> 
> Truly, the best answer is to follow the door sticker. By doing so, you get the *best combination* of ride, handling, safety, and mileage. Sure, changing the pressures can increase performance in one or more of those areas, but it can be at the sacrifice of one or more of the other factors. It'll be up to you to decide what you like best.


What I left out of my answer is that it also depends on the tire. Good quality tires aren't likely to skip around when inflated to their max pressure unless there is a problem with the suspension. Poor quality tires are more likely to skip. This is why part of my answer implied you need to test to see what works for you, your car, and your tires.

The Cruze is desgned to have all four tires at the same pressure. Putting more pressure in the front will lead to cornering stability problems. However, 1 PSI difference shouldn't make a noticable difference in cornering stability.

As for "best combination", once again this is subjective. For me the slightly "harsher" and noisier ride is worth it since it doesn't appear to impact my stopping distance or cornering and improves my MPG and tread life. In fact, my Goodyear FuelMax Assurance corner better at 45 PSI than they did at the door placard's 35 PSI. They also ride a lot better going over bumps in the road. They are slightly noisier. Professional race car drivers run their tires at max sidewall simply because they need the cornering stability. They aren't concerned with ride quality, but with traction and stability. Most drivers slow down when they see a yellow speed caution sign for a curve in the road. If I can see around the curve and the caution speed isn't extremely low (25 on a 55 MPH road, for instance) I don't slow down except for traffic in front of me. Having the extra pressure assisting the sidewall makes a difference.


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## gman19 (Apr 5, 2011)

I run 44psi cold for fuel economy purposes. Working pretty well so far!


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## GoldenCruze (Dec 18, 2011)

> As for "best combination", once again this is subjective. For me the slightly "harsher" and noisier ride is worth it since it doesn't appear to impact my stopping distance or cornering and improves my MPG and tread life. In fact, my Goodyear FuelMax Assurance corner better at 45 PSI than they did at the door placard's 35 PSI. They also ride a lot better going over bumps in the road. They are slightly noisier. Professional race car drivers run their tires at max sidewall simply because they need the cornering stability. They aren't concerned with ride quality, but with traction and stability. Most drivers slow down when they see a yellow speed caution sign for a curve in the road. If I can see around the curve and the caution speed isn't extremely low (25 on a 55 MPH road, for instance) I don't slow down except for traffic in front of me. Having the extra pressure assisting the sidewall makes a difference.


You have a different tire and wheel combination than I do, and that's why I stick with the term best combination. What a race car is set up for is completely different than a Cruze.


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## GoldenCruze (Dec 18, 2011)

> I run 44psi cold for fuel economy purposes. Working pretty well so far!​




I believe you. But here's the rub. I know that you have a different tire and wheel combination than I do, so what works for your car may not work for mine. And that's a problem in various threads here discussing tire pressures. People state their tire pressures without stating what tires and rims they have. Leaves it looking like a recommendation for all Cruzes. There many different tires on the Cruzes when they are shipped from the factory.​


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## jblackburn (Apr 14, 2012)

I went up to 42 PSI on the Firestones the 1LT/LS models come with. The ride was unbearable - reminded me of my old car with the "sports package" struts. We have totally crappy roads around here - patches over patches. Went back down to 38 PSI all-around, and the ride is tolerable, and the tires aren't as squishy going around corners. I can't wait til I can get some new ones.


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## obermd (Mar 3, 2012)

I ran both my Pontiac minivans at door placard +5 and never had any handling problems. Treated them like they were alternately jeeps, trucks , and sports cars for 22 years. My comment about race cars running at max sidewall was more to point out that if you can handle the car with stiffer tires and don't mind slight extra road noise and the loss in cushining, do it. If your road conditions, suspension, comfort levels, and driving habits won't support max sidewall PSI, then definitely don't run at max PSI.

Even for the same car with the same tires, different drivers are going to want to use different pressues inside the range of Door Placard - max sidewall. Each driver will have to make this determination for him/her self. As long as your COLD PSI is BETWEEN the DOOR PLACARD and MAX SIDEWALL PSI and your treadwear is uniform across the width of the tread, your tire pressure is CORRECT.


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## Skraeling (May 30, 2012)

tried 44 psi on my conti dws's on my wrx and the tires didnt like it started to wear funny.


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## jblackburn (Apr 14, 2012)

Why does a WRX apply to this discussion at all? It's a totally different car with totally different tire sizes.


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## Skraeling (May 30, 2012)

jblackburn said:


> Why does a WRX apply to this discussion at all? It's a totally different car with totally different tire sizes.


Better tell ober that he shouldnt mention his van then either. My point was it will vary car to car tire to tire.


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## obermd (Mar 3, 2012)

Skraeling said:


> Better tell ober that he shouldnt mention his van then either. My point was it will vary car to car tire to tire.


You are correct - it will vary from car to car, from tire to tire, and driver to driver. I do think that GoldenCruze should be concerned that less than a 5 PSI increase from the door placard is causing handling problems, however.


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## Macman (May 4, 2011)

I have the same tires as the OP. I'm running 35 psi cold all around, door plate says 32, left the llot at 33. Though I've felt a lot of vibration lately and the guys at discount tire can't find any issues other than the air pressure being high.


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## ErikBEggs (Aug 20, 2011)

I have an LTZ as well, I run 38 psi cold. I actually just got my car out of service Saturday for it's 22,500 mile tire rotation. My tread depth is 9/13 I have no idea what the number means but it was "green" on the sheet. Guy said these tires will last anywhere from 30K to 60K miles, I appear to be headed towards the 60K tire life... Also commented that the LTZ Michelin Pilots are simply a better tire than what is on the other trims.

Recommended tire pressure I think is anywhere from 10-30% higher than the door listing. The max tire pressure seems to be 50% higher than that value. As mentioned, you can safely run up to the max but I doubt you will benefit much from pushing it that high


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## rustinn (Jun 7, 2012)

And I forgot to mention, the technician who blew air into my tires didn't screw back the tire caps for the right side tires. Wonderful.


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## NBrehm (Jun 27, 2011)

ErikBEggs said:


> Recommended tire pressure I think is anywhere from 10-30% higher than the door listing.


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## rbtec (Feb 3, 2012)

70AARCUDA said:


> ...I believe he's referring to the fact that tire "load" capacity increases with increased air pressure, thus, 10-30% above the door sticker "soft" 30 psi would only be something like 33-39 psi, which would firm up the ride, but still be _less than _the tire max pressure of 41 or 44 psi.


30 psi seems really low, anyways. I've never known a recommended pressure below 32. I have mine at 36.


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## XtremeRevolution (Jan 19, 2012)

rbtec said:


> 30 psi seems really low, anyways. I've never known a recommended pressure below 32. I have mine at 36.
> 
> 
> Sent from my Autoguide iPhone app


They did recommend below 32 psi for the Ford Explorers with Firestone tires back in the 90s. We all know how that turned out...

Here's how it works. 

The higher the pressure, the less rolling resistance. The less rolling resistance, the less heat generated. The less heat generated, the less sidewall temperature increase at higher speeds. The less sidewall temperature generated, the less irreversible rubber degradation occurs, which in turn increases your tire life in addition to the additional tire life realized you get from a reduction in rolling resistance.

The tradeoff? Ride quality. Your results will vary based on what you set your pressure to. Don't go under placard ratings and don't go over sidewall maximum, measured "cold" for that season. 

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## GoldenCruze (Dec 18, 2011)

> The higher the pressure, the less rolling resistance. The less rolling resistance, the less heat generated. The less heat generated, the less sidewall temperature increase at higher speeds. The less sidewall temperature generated, the less irreversible rubber degradation occurs, which in turn increases your tire life in addition to the additional tire life realized you get from a reduction in rolling resistance.


All true. 

But!

Less rolling resistance happens because the contact patch is smaller. With less rubber meeting the road, stopping power is reduced. While not a real issue during a normal stop, a panic stop could mean that the car skids farther.


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## obermd (Mar 3, 2012)

The contact patch isn't that much smaller. In any case, the smaller patch also means less tread to float on top of water, so wet traction isn't impacted as much as you would expect.


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## spacedout (Dec 7, 2010)

GoldenCruze said:


> All true.
> 
> But!
> 
> Less rolling resistance happens because the contact patch is smaller. With less rubber meeting the road, stopping power is reduced. While not a real issue during a normal stop, a panic stop could mean that the car skids farther.


You actually don't have less contact patch with higher air pressure, you have a more consistent contact patch. An under inflated tire(like 30psi) the center of tire barley touches the road yet the edge sidewall is squished out with most of the pressure on the edge of tire. evening out the pounds per square inch of contact(instead of weight mostly on the edge of tires) equals better traction & less rolling resistance. 

I have had my car(a 1LT with firestones) set at 38psi cold but think I may back it off a bit since on some road surfaces the ride is harsh(hear/feel every bump). Anyone else experience this? This could just be the crappy tires(read online these firestones are known to develop "the thump".


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## jblackburn (Apr 14, 2012)

spacedout said:


> You actually don't have less contact patch with higher air pressure, you have a more consistent contact patch. An under inflated tire(like 30psi) the center of tire barley touches the road yet the edge sidewall is squished out with most of the pressure on the edge of tire. evening out the pounds per square inch of contact(instead of weight mostly on the edge of tires) equals better traction & less rolling resistance.
> 
> I have had my car(a 1LT with firestones) set at 38psi cold but think I may back it off a bit since on some road surfaces the ride is harsh(hear/feel every bump). Anyone else experience this? This could just be the crappy tires(read online these firestones are known to develop "the thump".


Same car. I backed mine off to 36 psi from 38 and the ride is much more tolerable.


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## obermd (Mar 3, 2012)

Does the Volt run the same Goodyear FuelMax Assurance as the Cruze ECO? Also, I noticed that GM is upping the recommended tire pressure at least for the ECO as part of this recall. You won't find it on the hacked cars, but you will find it on the new cars with the redesigned splash shield.


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## XtremeRevolution (Jan 19, 2012)

spacedout said:


> You actually don't have less contact patch with higher air pressure, you have a more consistent contact patch. An under inflated tire(like 30psi) the center of tire barley touches the road yet the edge sidewall is squished out with most of the pressure on the edge of tire. evening out the pounds per square inch of contact(instead of weight mostly on the edge of tires) equals better traction & less rolling resistance.
> 
> I have had my car(a 1LT with firestones) set at 38psi cold but think I may back it off a bit since on some road surfaces the ride is harsh(hear/feel every bump). Anyone else experience this? This could just be the crappy tires(read online these firestones are known to develop "the thump".


Agreed. Testing has already be done on this. Wet stopping traction is unaffected by tire pressure. In fact, hydroplaning resistance is improved with higher tire pressures.

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## NBrehm (Jun 27, 2011)

70AARCUDA said:


> ...FWIW, the 2012 VOLT OEM tire pressures are 38 psi.


The Volt also weighs ALOT more (roughly 800 pounds over the ECO) so you NEED the increased tire pressure for load bearing reasons (assuming the same size tire) , it has nothing to do with gas mileage


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## obermd (Mar 3, 2012)

NBrehm said:


> The Volt also weighs ALOT more (roughly 800 pounds over the ECO) so you NEED the increased tire pressure for load bearing reasons (assuming the same size tire) , it has nothing to do with gas mileage


:signs053: The Cruze is 1,000 lbs lighter than my Montana, yet the non-ECO versions have the same tire pressure requirements as my 4,000 lb Montana had. The LS has a smaller tires than the Montana and the LTZ has larger tires. I suspect it has more to do with rolling resistance. The Volt and ECO both need the lowest rolling resistance they can get. Frankly, GM should have designed the suspensions on both for 40 or 45 PSI.


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## JeffBazell (Jan 24, 2012)

2012 Eco, 17 inch. 41 cold, 45 after a good highway drive. All four equal. Yes, a little noisier but love the better handling and slightly stiffer ride.


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## obermd (Mar 3, 2012)

JeffBazell said:


> 2012 Eco, 17 inch. 41 cold, 45 after a good highway drive. All four equal. Yes, a little noisier but love the better handling and slightly stiffer ride.


I ran at 41 cold for a couple of months and then went to 45 cold. My MPG noticably improved at 45 and I couldn't tell the difference in road grip, feel, and handling. They run at 49-50 hot (100+) temps outside.


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## NBrehm (Jun 27, 2011)

obermd said:


> :signs053: The Cruze is 1,000 lbs lighter than my Montana, yet the non-ECO versions have the same tire pressure requirements as my 4,000 lb Montana had. The LS has a smaller tires than the Montana and the LTZ has larger tires. I suspect it has more to do with rolling resistance. The Volt and ECO both need the lowest rolling resistance they can get. Frankly, GM should have designed the suspensions on both for 40 or 45 PSI.



If you didn't have the same assurance fuelmax tire on the montana than your argument is irrelevant. What size were the montana tires? what brand, how many ply? Load range? Aspect ratio? If the volt has the same size of the same tire as the eco it will REQUIRE more air pressure to keep the shape of the tire correct, otherwise it will compress out like a flat tire.


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## obermd (Mar 3, 2012)

The Montana AWD tires were 225/60R16 98T. The 98T is 1653 lbs load limit per tire and 118 MPH speed rating. I had the GM load distributing hitch designed for the Montana AWD, so it was rated for 3,500 lbs towing with a max tongue weight of 500 lbs. A load leveling air suspension kept the van level under heavy load. GVWR was somewhere around 5,400 lbs, which gave it an interior load limit of 1,400 lbs and a tire load safety margin of 300 lbs per tire. Turns out that other than the GM OEM tires, the closest I could find aftermarket was 97V or 98H. I chose the 98H whenever available to avoid reducing my load rating by 88 lbs per axle. The AWD Montana had air friction limited top speed right about 100 MPH, so the speed T rating was appropriate. Door placard tire pressure was 30 PSI Front and Rear. I ran at 35 PSI.

I frequently pulled a Boy Scout troop trailer weighing close to 3,000 lbs with a couple hundred pound tongue while loading up the inside of the van with close to 1,000 lbs of scouts and personal gear. At 35 PSI I never had tires buldge, nor did the van ever have problems with overheating or braking except during one April blizzard when the Versatrak system was continuously engaged to climb US 86 from Franktown to Castle Rock. The road was covered in about 10 inches of freshly fallen snow.

My experiences with the Montana is a perfect example of the 100% correct comments in this and other threads about the right tire making a world of difference. While I was running Bridgestones the Montana never broke traction unless I was trying to do so, and even then it was extremely hard to brake traction. The last set of tires I put on it were Michelins. They broke traction all the time and were obviously not the right tire for the vehicle.


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## NBrehm (Jun 27, 2011)

Ok so the max load for a 215/55/17 assurance Fuel max is 1477 pounds, so the tire on your Montana (being wider and having more sidewall) can support more weight at the same PSI. Hence being able to run a heavier vehicle with the same air pressure. So again, if the Volt uses the EXACT same tire as the Eco, and weighs 800 pounds more, the recommended tire pressure will be higher to compensate for the roughly 200 pounds per wheel weight increase.

From Bridgestone:
*" Tires aren't like balloons. They don't get bigger when more air is pumped into them. Their volume stays pretty much the same-the pressure just rises. You could say it's the number of air molecules inside that determines the maximum load. Higher pressure means more air molecules and higher capacity. And, a bigger tire can contain more air molecules-and therefore has more capacity-than a smaller tire at the same pressure.* *A heavier load means more "squash" at a given pressure. So, you need a higher pressure with a higher load*.*"*


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