Tire air pressure

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Shawn Burns

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I have a 16 Rebel. The door sticker recommends 55 front and 45 rear for the air pressures. The truck came stock with Toyo Open Country A/T. I now have Falken Wild Peak's on there with an 80 lb. max. Should I stick with what the door label says or increase them closer to the max? I've been running them at 60f and 50r when I town, just as I did with the Toyo's. The ride is improved since I switched to the Toyo's. Thanks in advance.
 

danielmid

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What size Falkens? I run my Wildpeak 35x12.5R17s at 40psi whenever I'm not towing or heavy loaded. No reason to run near max, and I can't imagine how bouncy the ride must be with 60/50 all the time.
 

Daniel Ortiz

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@Shawn Burns , if your new tires are the same size specification as your old tires, use the same pressures you were using before.

If the size is different, you can use this handy calculator to get a reasonably good modified pressure based on load carrying capacity.

Both gentlemen above are correct, in a way. Your door sticker pressures are the "official" pressures you should run your vehicle at, and take into consideration load-carrying capacity, handling, and wear. But, recognize if you have a good reason to run a little lower, you can, because you probably aren't carrying maximum load in your vehicle. But doing so also reduces vehicle handling (especially in emergency manuvers). So make sure your reason is a good one (like going over bumpy roads, added traction at slower speeds, etc.). Also remember running tires TOO low (on the order of 10+ psi too low) will cause them to heat up more than normal at higher speeds, and if they heat up too much, they will start to degrade (damage) internally, and end up weaker than when you started.

Understand that the maximum psi labeled on the tire is the tire's MAXIMUM pressure at which point the tire is at it's maximum load-carrying capacity (within safety factors). But if your truck can't even carry that much load (it can't, at least officially), you don't need to air them up that high. Basically, when considering load-carrying capacity alone (not considering handling or wear or toughness), you only have to air up a tire to the pressure corresponding to the load you need to carry. For your truck's maximum loading capacity, that pressure is probably close to the pressures on your door sticker. Hence, if they are the same size as your previous tires, you can continue to use the same pressures as before. If your previous size was also stock size, the door sticker pressures are a good reasonable place to start.
 
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Kootbiker

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I ran the door sticker pressures on the original Goodyear Duratracs, 45psi rears and 55psi fronts, ride was very good. Just replaced the worn out Duratracs with Coopers equivalent tire. I am trying 43 psi in the rear and 53 psi in the front because the Duratracs lost most of their tread from the center of the tire which makes me think they were overinflated.
 

gofishn

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The sticker is the recommended pressure for the OEM tire's size and rating.
You have changed the tires, to a much stringer side wall. so the tag really does not apply, any longer.

Find your tire, in the chart below, which comes from RAM themselves.
Do no forget the weight of your truck. Add what you normally haul, carry or tow,
to the trucks weight, then find your tires, and see what pressure Ram says you should run.

hear is a link to RAMs tire pressure charts:



here are the charts themselves.
Remember, your tires, at whatever pressure you run, must still handle the weight of the truck.

ram tire pressure chart-1.jpg


ram tire pressure chart-2.jpg

Running tire pressure, too low or too high, will affect tire wear. darn quick.
So, check your tires, regularly, once you decide on a pressure, to make sure your tires are not getting chewed up.



Tire Wear.jpg


Good Lucka nd come back with what you find the best pressure to be so the next guy, with your same issue, can fidn the answer with teh search tool.

Luck
 

Dean2

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The tire pressure required is strictly determined by the tire and the load being carried. Over inflated is every bit as bad as underinflated. This link has all make and sizes of tires. Match your tire and and the weight you are running your truck at. On my 2500, I run way less pressure empty about 45 psi and go up in pressure as I increase the load to about 70 psi at max load. My door sticker says 60 front and 65 back for the stock OEM Firestone Destination ATs of the same size.

Also, don't forget the effect of heat and cold on the actual pressures you are running.

https://tirepressure.com/lt275-70r18-tire-pressure
 
OP
OP
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Shawn Burns

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Thanks for all of the responses. That is very helpful. FYI, I kept the same size and load of the original tires. They are 285/70-17 10 ply, E rated 121 load index.
 

atreides

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Do this and you will really know.

This is the way. I've always used the chalk test as well. My current 37s are good to go at 32 PSI unloaded.
 

Dinky

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This is the way. I've always used the chalk test as well. My current 37s are good to go at 32 PSI unloaded.

Yep you will get the best ride quality to tire wear .
 

Daniel Ortiz

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I have thoughts and considerations. Not advice, mind you, but considerations for chewing on.

I feel like the chalk test gets the best results for wear (and of course a nice cushy ride to boot), and thus loading (but only at the load at which the chalk test was performed at), however it neglects any research that has been done by the manufacturer in terms of ability to swerve or perform other emergency maneuvers without destabilizing the vehicle too much. In fact, that's why I think the Rebels have such high tire pressures (55 front, 45 rear). They don't have any added carrying capacity over my Express Quad Cab which has (39 front, 39 rear). But they do have thicker tires, which allow for more roll in a swerve, and so they may have increased their stock pressures to account for that. Yes, I know Rebels may be heavier with their ram boxes, crew cabs, and air suspension, but I don't think that justifies going from 39 to 45/55. I think there is some additional reason to justify the larger tire pressures, especially the elevated front pressure, and I believe that reason is stability during emergency maneuvers, which they determined during testing. If that is true, that means stability is also engineered into EVERY truck's tire pressures printed on their door sticker. Going by the chalk test only gives up that stability.

Now, the fix for this is to simply drive more conservatively and defensively, so you reduce your chance of having to make an emergency swerve. But we all know sometimes you can't avoid such a situation, and that is the moment (and probably only moment) those increased tire pressures would save you from rolling, and whatever ill effects may come from that.

So, chalk test is great for determining the best pressure for your (probably) unloaded vehicle, the "light" load condition if you will. But as soon as you add meaningful weight, whether it be passengers, cargo, trailer, whatever, you'd either need to perform a new chalk test at the new load to figure the new best pressure, or interpolate between your "light" chalk test pressure and fully loaded pressure on your sticker (you'd have to know the weight you added), or just jump right up to your door sticker pressures, which do take max load capacity into account, plus stability.

Anyhoo, interesting thoughts.
 

Dinky

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I have thoughts and considerations. Not advice, mind you, but considerations for chewing on.

I feel like the chalk test gets the best results for wear (and of course a nice cushy ride to boot), and thus loading (but only at the load at which the chalk test was performed at), however it neglects any research that has been done by the manufacturer in terms of ability to swerve or perform other emergency maneuvers without destabilizing the vehicle too much. In fact, that's why I think the Rebels have such high tire pressures (55 front, 45 rear). They don't have any added carrying capacity over my Express Quad Cab which has (39 front, 39 rear). But they do have thicker tires, which allow for more roll in a swerve, and so they may have increased their stock pressures to account for that. Yes, I know Rebels may be heavier with their ram boxes, crew cabs, and air suspension, but I don't think that justifies going from 39 to 45/55. I think there is some additional reason to justify the larger tire pressures, especially the elevated front pressure, and I believe that reason is stability during emergency maneuvers, which they determined during testing. If that is true, that means stability is also engineered into EVERY truck's tire pressures printed on their door sticker. Going by the chalk test only gives up that stability.

This is kinda wrong. Each tire is engineered differently and have different specs and size. Each tire will have different pressure depending on diameter,width and rim size. ALL tires are designed to make full contact evenly across the whole tread pattern. This is where the tire will perform the best as that was the design. This will reflect the stability of your vehicle as the tire has a weight rating to get the tire to have even contact. I have toyo AT3s on my wife's jeep her tires are set 35psi in the front and 32 in the rear now max pressureis 55psi. My 3500 has the same tires but F rated and bigger. My front are set to 60psi rear is 52psi max pressure is 90psi. When we go on trip or I haul a load I change air pressure as the weight changed. I typically don't change my truck pressure if I am doing in town hauling but long trips in the summer I definitely will.
 

Dean2

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This is kinda wrong. Each tire is engineered differently and have different specs and size. Each tire will have different pressure depending on diameter,width and rim size. ALL tires are designed to make full contact evenly across the whole tread pattern. This is where the tire will perform the best as that was the design. This will reflect the stability of your vehicle as the tire has a weight rating to get the tire to have even contact. I have toyo AT3s on my wife's jeep her tires are set 35psi in the front and 32 in the rear now max pressureis 55psi. My 3500 has the same tires but F rated and bigger. My front are set to 60psi rear is 52psi max pressure is 90psi. When we go on trip or I haul a load I change air pressure as the weight changed. I typically don't change my truck pressure if I am doing in town hauling but long trips in the summer I definitely will.
Spot on. Handling differences between tires is WAY more affected by tire design than by the air pressure. There is no way in hell that manufacturers set tire pressure by testing tire handling. My 2021 2500 comes with 18 and 20 inch tires and more than 5 different tire choices as ordered. The 18 inch tire option all have the same recommended pressures regardless of tire make or design. Not sure the 20 inch ones have the same recommended inflation but I would bet they do.

Door sticker tire pressure is based on accommodating the max rated payload, towing rating. It sure isn't handling characteristics.
 

Dinky

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Spot on. Handling differences between tires is WAY more affected by tire design than by the air pressure. There is no way in hell that manufacturers set tire pressure by testing tire handling.

Each tire design has its own purpose. You could skip the caulk test and just do the math base off of max tire pressure max weight. You just need to know your front end and rear end weight and calculate out the % difference. I suck at math so I just do the caulk test
 

Dean2

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Each tire design has its own purpose. You could skip the caulk test and just do the math base off of max tire pressure max weight. You just need to know your front end and rear end weight and calculate out the % difference. I suck at math so I just do the caulk test
Agree. That is why I posted the link to the tire pressure chart. Covers every size and make and the pressure by weight per tire. No math needed.
 

Dinky

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Agree. That is why I posted the link to the tire pressure chart. Covers every size and make and the pressure by weight per tire. No math needed.
No 35in tires on that chart worthless:p
 

Dean2

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No 35in tires on that chart worthless:p

No 35in tires on that chart worthless:p
People like you are almost impossible to help. You are so focused on proving how smart you are and how dumb everyone else is that you don't even bother to check out the information we take a lot of work to provide. Just one example of 35 inch from the same site. They go way up in size from there. If you can't use a computer or simple search function, don't blame it on me.

 
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