Tire inflation

[kkinna]

Do you fill the air in your tires to the psi number stated? My Frontier came with the tires inflated to 30psi, when the psi on the tires was 50psi. I inflated them all up to 50psi, which raised the truck up by about an inch, and made for a bouncier ride. I now have them at 45psi to see what that does.

What do you all do?

Thanks, Kim

[cpaharley2008]

I always keep my truck and trailer at max which is 40 truck and 50 trailer.

[padlin]

There's a sticker inside the door of my F150 that tells me what to put them at.

[float5]

I no longer have tires that came with the car. Whatever tires you have, the psi should be on the door jamb and that is all you need. My tires have a much higher number on the sidewall than the psi on the doorjamb so that I could add some "extra" if I wanted, but no real reason to do so.

[Brian B-P]

Originally Posted by kkinna

Do you fill the air in your tires to the psi number stated?

Yes, I use the air pressure stated by the vehicle's manufacturer in the manual and on the placard on the vehicle.

The 2017 Nissan Frontier owner's manual explains the placard (label) - starting on page 8-31 - and lists the correct pressure (on page 8-33). Although there are various sizes of tire offered with the Frontier (which can often mean different inflation pressures), the manual lists 35 PSI for all sizes, both front and rear.

Originally Posted by kkinna

My Frontier came with the tires inflated to 30psi, when the psi on the tires was 50psi. I inflated them all up to 50psi, which raised the truck up by about an inch, and made for a bouncier ride. I now have them at 45psi to see what that does.

Why did you do this? The pressure marked on the tire sidewall is clearly shown as a maximum inflation pressure. At 50 PSI your tires are probably Load Range C light truck tires, or possibly Extra Load (XL) P-metric or euro-metric tires. It is far too high for that tire on that vehicle, which is why using that excessive pressure causes all of the problems you have seen... and more. The tires will also wear more in the centre, and have less traction.

[Patandlinda]

Originally Posted by float5

I no longer have tires that came with the car. Whatever tires you have, the psi should be on the door jamb and that is all you need. My tires have a much higher number on the sidewall than the psi on the doorjamb so that I could add some "extra" if I wanted, but no real reason to do so.

Replaced tires on the Subie and so far because of gas mileage big drop ,have added 8 lbs to front and 6 to rear . New tires say 40 lb . Door sticker says 32 and 30 . Still under cold pressure of new tires but gas mileage has picked up and so far rides nice . Pat

[dfandrews]

We run with tire pressure on the tow at maximum, because we are fairly near max. on tow vehicle weight, and we want maximum gas mileage and traction. We run the Escape at 44 psi based on the trailer weight. If it were higher, we'd get uneven wear in the tread center, and more bouncing.

[Chotch]

Originally Posted by kkinna

Do you fill the air in your tires to the psi number stated? My Frontier came with the tires inflated to 30psi, when the psi on the tires was 50psi. I inflated them all up to 50psi, which raised the truck up by about an inch, and made for a bouncier ride. I now have them at 45psi to see what that does.

What do you all do?

Thanks, Kim

Over inflated tires wear badly, provide less traction, this includes braking, and ride harsh. The manufacturer gives pressure rating for highest load possible. If you need 50 psi on a Frontier I guarantee you are exceeding your GVW by a lot. You may see better mileage but at the expense of all of the above.

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[TheWanderers]

I always fill my tires based on what the tire manufacturer recommends. The vehicle manufacturer doesn't know who made the tires or what that tire manufacturer requirements might be.

It's my opinion that the sticker on the door frame is there to help you determine what tire size should be applied to the vehicle in the stock configuration and provides the GVWR as well as the GAWR for each axle based on the rim sizes and tire sizes included at the time of sale. This sticker doesn't take into account the opportunity for someone to change the rims or tire size after the initial sale.

I believe that the tire manufacturer is better qualified to determine what pressures should be used in their tires. Visit any tire shop and they'll be willing to tell you about under-inflation generating heat that may cause ply separation or a blow out, cupping or excessive shoulder wear.

Off roaders will tell you that they reduce the pressure in their tires to improve traction in specific circumstances that may include loose sand, snow or mud. However, these same people will carry a compressor to re-inflate before returning to the road.

Of course, with all that said, it's your vehicle, and, YMMV

[Donna D.]

Originally Posted by TheWanderers

I always fill my tires based on what the tire manufacturer recommends. The vehicle manufacturer doesn't know who made the tires or what that tire manufacturer requirements might be.

I'm of the same thought. I think the tire manufacturer knows more about their product than the manufacturer of the motor vehicle.

[float5]

The tire manufacturer has no idea of the weight of the vehicle that the tire is going on. The psi on the door jamb is for that vehicle.

That said, Carlisle for our trailer tires, says to put the psi at the 50 that they have on the tires. Trailer tires are not constructed the same as other tires.

[thoer]

There is apparently some confusion about tow vs trailer tire pressures here. Most trailer tire manufacturers recommend running at the max pressure as that gives the highest weight rating. That has been discussed here on many different threads and can be found here.

On your tow, the max tire pressure stamped on a tire, is just that - the maximum pressure you can safely put into that tire, not a recommended inflation pressure for any specific vehicle. My guess is that any tire manufacturer is going to refer you back to your owners manual, and or the label on the door frame of every vehicle. Your manual will also list acceptable tire sizes and the vehicle manufacturer's specified pressure for each size.

[Bill and Earline]

Just as I was about to jump into this discussion, I see that Cathy and Eric have said what I was going to say.

I am glad the forum got me to check my tires, since the temperature has dropped 40 degrees since I last checked my tires a month ago, and readings were down, predictably, by 4 psi in each vehicle.

Consider the following vehicle door jamb recommendations and tire manufacturer max psi:

2014 Audi A6 Fr44 Rr46 Max51
2016 Ram Fr 39 Rr 39 Max 44
1999 Corvette Fr30 Rr 30 Max 51
2003 4Runner Fr32 Rr 32 Max 44

I go a couple of pounds over in the older cars, and stick pretty close to the vehicle manufacturer in the newer ones. As long as a person is within a few pounds of vehicle manufacturer specifications, that would seem safe.

Check tires often as we head into winter.

[padlin]

Never looked at it this way, but my tires say 80 lbs max, truck info says 55/60. Think I'll continue to do what the truck says.

From the F150 manual.
"Always inflate your tires to the Ford recommended inflation pressure even if it is less then the maximum inflation pressure info found on the tire. The Ford recommended tire inflation pressure is found on the Safety Compliance Certification Label." it goes on to tell you where the sticker is.

The same tires can fit on a multitude of vehicles.

[Bobbito]

My Bridgestone Dueler heavy duty tires allowed up to 80 psi, but I ran them at 55 psi around town for the longest time. Then my mechanic showed me that even that pressure was too much without a load. They wore out prematurely in the middle with lots of tread on the sides. My new tires I'm running at 45 psi unless I have the truck loaded and am pulling the trailer. Then I bump them up to 55 psi. Even though the truck is at its maximum load (boat, motor, canopy, gear, trailer, etc.) the tires aren't fully loaded. Clearly the tire load capacity exceeds that of the truck. You really can't just go blindly with the tire manufacturer's maximum pressure, at least with your tow vehicle.

KalTire said you can check to see if your tires have the right amount of air by running your loaded tires from wet onto dry pavement and observing the pattern. If they make good contact across the tread you have the pressure about right.

Bob K

[caddoster]

In CA there's a tire inflation regulation that requires the service providers to set the tire pressure to whatever is "recommended"..

one of the things that annoys me when my FJ was in for service is they would deflate the tires to 32psi (as stated on the door).. I didn't have the original tires and I usually run them at 40psi.

[Chotch]

Originally Posted by TheWanderers

I always fill my tires based on what the tire manufacturer recommends. The vehicle manufacturer doesn't know who made the tires or what that tire manufacturer requirements might be.

It's my opinion that the sticker on the door frame is there to help you determine what tire size should be applied to the vehicle in the stock configuration and provides the GVWR as well as the GAWR for each axle based on the rim sizes and tire sizes included at the time of sale. This sticker doesn't take into account the opportunity for someone to change the rims or tire size after the initial sale.

I believe that the tire manufacturer is better qualified to determine what pressures should be used in their tires. Visit any tire shop and they'll be willing to tell you about under-inflation generating heat that may cause ply separation or a blow out, cupping or excessive shoulder wear.

Off roaders will tell you that they reduce the pressure in their tires to improve traction in specific circumstances that may include loose sand, snow or mud. However, these same people will carry a compressor to re-inflate before returning to the road.

Of course, with all that said, it's your vehicle, and, YMMV

The tires manufacturer has no idea where his tires are going. Look at max load rating on your tire, multiply by 4 and check your GVW. If it is the same then by all means use max inflation, I think you will find the GVW to be 50 to 75% of the # you came up with. No vehicle manufacturer is putting tires on a vehicle that barely meets his GVW. On your tire I believe it will say x psi at max weight.
With liability laws as they are today does anyone believe a manufacturer would print a sticker for each and every vehicle for every lawyer in country to see that had false or dangerous info??

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[Brian B-P]

Originally Posted by TheWanderers

I always fill my tires based on what the tire manufacturer recommends.

That would mean that you consulted the load-inflation tables to determine the minimum pressure, and the sidewall of the tire for the maximum pressure... but where did you find a recommendation from a tire manufacturer of the correct inflation for your vehicle?

Originally Posted by TheWanderers

The vehicle manufacturer doesn't know who made the tires or what that tire manufacturer requirements might be.

That's not really true. While they don't know who will have made the tires that you install, all tires legally sold for street use are built to industry standards (from the Tire & Rim Association or the European Tyre and Rim Technical Organisation), so as long as you installed tire consistent with the vehicle manufacturer's design, the vehicle manufacturer knows the dimensions, load capacity, speed rating, and other characteristics.

And as others have mentioned, the vehicle manufacturer knows much more about the tires than the tire manufacturer could possibly know about the vehicle.

Originally Posted by TheWanderers

It's my opinion that the sticker on the door frame is there to help you determine what tire size should be applied to the vehicle in the stock configuration and provides the GVWR as well as the GAWR for each axle based on the rim sizes and tire sizes included at the time of sale. This sticker doesn't take into account the opportunity for someone to change the rims or tire size after the initial sale.

It also specifies tire minimums - any other tire you choose needs to have at least the same load capacity and speed index, and logically at least the same section width and the same overall diameter.

If you are changing to a size other than any of the factory-offered sizes, you're doing your own design work. The people who do this for a living and take responsibility for the safe design of the vehicle don't just pick the maximum inflation pressure off the sidewall. In motorsports, it is routine to examine the profile of tread temperatures across the face of the tire in operating conditions to guide adjustment of pressure.

Originally Posted by TheWanderers

I believe that the tire manufacturer is better qualified to determine what pressures should be used in their tires. Visit any tire shop and they'll be willing to tell you about under-inflation generating heat that may cause ply separation or a blow out, cupping or excessive shoulder wear.

Yes, underinflation is bad. That's why the pressures recommended by the vehicle manufacturer are high enough to ensure that under-inflation problems do not occur.

Guy selling tires in a retail store, or team of engineers working for the vehicle manufacturer - who to believe? That's not really a tough one.

Originally Posted by TheWanderers

Off roaders will tell you that they reduce the pressure in their tires to improve traction in specific circumstances that may include loose sand, snow or mud. However, these same people will carry a compressor to re-inflate before returning to the road.

True. Appropriate inflation depends on operating conditions. The conditions considered by the vehicle manufacturer are not extreme off-roading at a crawling speed, they are urban and highway operation at any legal speed and with the vehicle loaded to its rated capacity.

[Patandlinda]

Originally Posted by Brian B-P

That would mean that you consulted the load-inflation tables to determine the minimum pressure, and the sidewall of the tire for the maximum pressure... but where did you find a recommendation from a tire manufacturer of the correct inflation for your vehicle?


That's not really true. While they don't know who will have made the tires that you install, all tires legally sold for street use are built to industry standards (from the Tire & Rim Association or the European Tyre and Rim Technical Organisation), so as long as you installed tire consistent with the vehicle manufacturer's design, the vehicle manufacturer knows the dimensions, load capacity, speed rating, and other characteristics.

And as others have mentioned, the vehicle manufacturer knows much more about the tires than the tire manufacturer could possibly know about the vehicle.


It also specifies tire minimums - any other tire you choose needs to have at least the same load capacity and speed index, and logically at least the same section width and the same overall diameter.

If you are changing to a size other than any of the factory-offered sizes, you're doing your own design work. The people who do this for a living and take responsibility for the safe design of the vehicle don't just pick the maximum inflation pressure off the sidewall. In motorsports, it is routine to examine the profile of tread temperatures across the face of the tire in operating conditions to guide adjustment of pressure.


Yes, underinflation is bad. That's why the pressures recommended by the vehicle manufacturer are high enough to ensure that under-inflation problems do not occur.

Guy selling tires in a retail store, or team of engineers working for the vehicle manufacturer - who to believe? That's not really a tough one.


True. Appropriate inflation depends on operating conditions. The conditions considered by the vehicle manufacturer are not extreme off-roading at a crawling speed, they are urban and highway operation at any legal speed and with the vehicle loaded to its rated capacity.

For us buying same size tire if you feel like your dragging along , I think new tires are heavier , and mileage has taken a real hit , time to put a little more aIr in tires but still under max tire pressure . How the vehicle is handling is a clue . Also watching tire wear in middle or edges of tires can tell you a lot . Like trailer tires , switching to Maxiss D tires which are heavier then the C Carlisles allowed us a little more air and if ever needed increase speed on highway . We don't like to drive over 65 though . From day one the original tires on the Subaru , going by what was posted on door jam , never felt operated right . Increased air pressure from the beginning 4 lbs over door jam information . Also checked with Subaru forum and found pretty common among owners to increase tire pressure for better operation . Now Ford F-250 states on door jam 80 rear and 51 front and have found even before bumper pull had a camper and never changed tire pressure and truck handled fine . So I believe there can be lots of variables with tire pressures . A lot can be common sense too. Tires are not the same . New tires on the Subaru are heavier then they were with originals . The Carlisles were lighter in weight then the Maxiss tire we now have . I think you have to get as much information as possible and you know how your vehicle is handling , go from there . I called many Subaru dealers and tire dealers and could not get a answer . So had to use a trial and error method to find that sweet spot . Pat

[kkinna]

Thank you all for your responses. It seems that there are a couple of different thoughts on this. My door info says to inflate the tires to 35psi, and the tires say 50psi. 30psi was definitely too low. At 45 psi, the ride is better than at 50psi. It also sounds like some of you add air when towing? I will try 40psi? Then 35psi. It seems weird that the manufacturer psi would be so off from the vehicles recommendation. Thank you for explaining that reason so eloquently.