Tire pressure! You make the call.

[Scott2008910]

OK… So I tried to do research on this. But doing a search for “what tire pressure should I use“ is in the realm of “what oil should I use“ it seems. But I haven’t been able to find an answer to this particular question.

So, assuming that everybody agrees to use the tire pressure stated on the sticker in the door jam for a truck with stock tires, What about in my case? My 2010 Sport came stock with the 20 inch Goodyear SR-A (P265/60/20). Tire pressure on the door jam 35 PSI. But in my case, I replaced them with OEM 17 inch Toyo Open Country 2 from a Rebel. ( LT285/70/17 ) Sticker on the door jam for that truck stated 55psi front, 45 psi rear.

Both trucks weigh about the same. Since the difference between the Sport and the Rebel, other than the air suspension on the Rebel, is more or less just an appearance package, what psi would you go with? Everything in question here are OEM parts.


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[UnsatFC]

I would go with the factory pressure for the tires you have, the rebel. I had factory 265/70R17’s on mine and he door sticker says 40 PSI all around however I have a set of factory 20’s...I never looked at the difference in PSI. Perhaps someone with a 2015’sh RAM with facotry 20’ Big Horn rims can provide what the door jam says for psi?

 

[hotrod45]

OK… So I tried to do research on this. But doing a search for “what tire pressure should I use“ is in the realm of “what oil should I use“ it seems. But I haven’t been able to find an answer to this particular question.

So, assuming that everybody agrees to use the tire pressure stated on the sticker in the door jam for a truck with stock tires, What about in my case? My 2010 Sport came stock with the 20 inch Goodyear SR-A (P265/60/20). Tire pressure on the door jam 35 PSI. But in my case, I replaced them with OEM 17 inch Toyo Open Country 2 from a Rebel. ( LT285/70/17 ) Sticker on the door jam for that truck stated 55psi front, 45 psi rear.

Both trucks weigh about the same. Since the difference between the Sport and the Rebel, other than the air suspension on the Rebel, is more or less just an appearance package, what psi would you go with? Everything in question here are OEM parts.


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The cross section of the tire is an important distinction when it comes to tire pressure. In this case, the 70 series tire demands a higher pressure; and the LT indicates that it is a light truck tire and therefore has a higher ply rating (which you should not ignore) and that also demands a higher pressure. Running higher ply rated tires too soft is an invitation for tread chunking.

 

[corneileous]

OK… So I tried to do research on this. But doing a search for “what tire pressure should I use“ is in the realm of “what oil should I use“ it seems. But I haven’t been able to find an answer to this particular question.

So, assuming that everybody agrees to use the tire pressure stated on the sticker in the door jam for a truck with stock tires, What about in my case? My 2010 Sport came stock with the 20 inch Goodyear SR-A (P265/60/20). Tire pressure on the door jam 35 PSI. But in my case, I replaced them with OEM 17 inch Toyo Open Country 2 from a Rebel. ( LT285/70/17 ) Sticker on the door jam for that truck stated 55psi front, 45 psi rear.

Both trucks weigh about the same. Since the difference between the Sport and the Rebel, other than the air suspension on the Rebel, is more or less just an appearance package, what psi would you go with? Everything in question here are OEM parts.


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Interesting.... I’d go with what the pressures said for the Rebel that you pulled them tires from.

The reason for the higher pressure is for the fact that those are LT tires, and not a P-rated tire like you had on there.

Do you know what ply those Rebel tires are? Max pressure on the sidewall is? I’m just curious because a set of BFG all-terrain KO/2’s I used to have on my truck were a 8 ply LT tire and a representative from BF Goodrich said I should be running them at 55 all the way around, and they were in the stock 20” size on my Ram Limited, which is 275/60/20.

But speaking of which, you sure your stock tire size is 265/60/20? The reason i ask is because even my 2008 Ram came with the 275/60’s, the same as my 18 came with.


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[corneileous]

The cross section of the tire is an important distinction when it comes to tire pressure. In this case, the 70 series tire demands a higher pressure; and the LT indicates that it is a light truck tire and therefore has a higher ply rating (which you should not ignore) and that also demands a higher pressure. Running higher ply rated tires too soft is an invitation for tread chunking.

I wondered about that when I was told to run my BFG’s I had, at 55psi.... but like I said in other threads regarding this, when I ran my BFG’s at 39- the factory recommended pressure for the stock Goodyear’s, they felt awful spongy and a little too flexible with a little too much give to them. Still rode rougher than hell but stopping and cornering wasn’t worth a **** until I aired them up to 55 all the way around which is what BFG said to run them at.


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[Scott2008910]

But speaking of which, you sure your stock tire size is 265/60/20? The reason i ask is because even my 2008 Ram came with the 275/60’s, the same as my 18 came with.


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Yes you are 100% correct. They are 275/60’s. Too many numbers to get it all right the first time. Lol. ( And I even re-read my post to check for errors before I submitted it.

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[corneileous]

Yes you are 100% correct. They are 275/60’s. Too many numbers to get it all right the first time. Lol. ( And I even re-read my post to check for errors before I submitted it.

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Ok, I was just wondering....[emoji846]

But it’s interesting that your 2010 says to run your factory Goodyear’s at 35, but my 18 says to run mine at 39. Even my 08 1500 on the stock 20” Goodyear’s said to run them at 35 too.

I’m guessing that’s just a fuel mileage thing set by Chrysler to get higher numbers? After seeing that I’m tempted to drop my new Michelin’s down to 35, get a little bit more ride out of them.



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[Scott2008910]

Oh yeah, I would totally believe that the higher pressure recommendation is for better fuel mileage numbers. The truck makers would sell their souls for the “best mpg” title and every little bit adds up. Not everyone is brand loyal and that might just get someone from Ford/Chevy.

As far as the ply number and max pressure, I’ll have to go look at them in the garage tomorrow.

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[Hogman338]

Read the tire load & inflation table it explains a lot.

https://www.toyotires.com/tires-101/tire-load-and-inflation-tables

 

[corneileous]

Oh yeah, I would totally believe that the higher pressure recommendation is for better fuel mileage numbers. The truck makers would sell their souls for the “best mpg” title and every little bit adds up. Not everyone is brand loyal and that might just get someone from Ford/Chevy.

That’s kinda what I figured. I just assumed when I bought the truck that it might’ve been from increased payload or something since theres 10 years difference from my old 08 to my new 18.

As far as the ply number and max pressure, I’ll have to go look at them in the garage tomorrow.

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I wouldn’t be surprised if those Rebel tires are in fact 8 -ply with a max pressure of 65psi if the Rebel you got them from days to run the fronts at 55. That’s outside the realm of 4-ply tires and most 6-ply’s I believe.




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[muddy12]

Surprised no one mentioned the chalk test yet.

Get some chalk, and find an empty parking lot.
Rub chalk across the tread of the tires, drive straight for a little bit, then check the chalk.
If the chalk is worn off in the center, your pressure is too high. If it’s worn on the edges, your pressure is too low. Adjust your pressure accordingly until the chalk wears off evenly across the width of the tire.

This will give you the optimum pressure for your particular truck and tire combination.




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[Scott2008910]

Surprised no one mentioned the chalk test yet.


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Yes, I have definitely come across the chalk test, and will give it a try. My question was what the opinions were as far as the door jamb sticker says. Seems like an interesting question. Do you go with the factory recommendations for the truck you have, or the recommendation for the truck that the tires came from, if everything is OEM and the trucks are basically the same.



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[corneileous]

Yes, I have definitely come across the chalk test, and will give it a try. My question was what the opinions were as far as the door jamb sticker says. Seems like an interesting question. Do you go with the factory recommendations for the truck you have, or the recommendation for the truck that the tires came from, if everything is OEM and the trucks are basically the same.



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If it were me, I’d just run them at 55 in the front, and 45 in the back, just like what the door sticker would say on your truck if you were driving an actual Rebel with the OEM wheels and tires.

I’m seriously thinking about dropping my new Michelin’s down to 35 instead of 39.


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[Mike Flea]

My door sticker says P265/70R17, 40psi front and rear.

The tires that are on the truck when I purchased it, are Michelin LTX M/S 275/60R20 & the max pressure on the sidewall states 44psi. I run them at 42psi front and rear

 

[6.7CumminsDrvr]

Load Infltion Table is your friend, need to take a look at this:

https://www.toyotires.com/media/2125/application_of_load_inflation_tables_20170203.pdf

 

[6.7CumminsDrvr]

Little info.........

Stock 275/60/20 Goodyears have a max capacity of 2601 lbs @ 44 psi but at 35 psi they carry the same 2601 lbs. But it’s a P metric size used on a light truck, it’s capacity is derated by a factor of 1.1. So the factory tires are really only rated to carry 2365 lbs.

If you look at the table a LT285/70/17 requires right around 42 psi to carry the same weight.....

 

[Longhorn1500]

Load Infltion Table is your friend, need to take a look at this:

https://www.toyotires.com/media/2125/application_of_load_inflation_tables_20170203.pdf

I was wondering when someone was going to mention this. Good job!!

 

[Scott2008910]

Load Infltion Table is your friend, need to take a look at this:

https://www.toyotires.com/media/2125/application_of_load_inflation_tables_20170203.pdf

I looked all over that site for that and missed it. Thanks! That’s 31 pages of reading!

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[Scott2008910]

If it were me, I’d just run them at 55 in the front, and 45 in the back, just like what the door sticker would say on your truck if you were driving an actual Rebel with the OEM wheels and tires.

I’m seriously thinking about dropping my new Michelin’s down to 35 instead of 39.


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Yeah, that makes sense to me too, and I’m gonna go that way. But we’ve all been told over and over since the beginning of time, to always go by the manufacturers recommendation on the sticker no matter what. Lol


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[muddy12]

Yes, I have definitely come across the chalk test, and will give it a try. My question was what the opinions were as far as the door jamb sticker. ..........
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I will typically use the door jamb sticker as a starting point, then chalk and adjust from there.
I’m running 35x12.5’s, and usually end up a little lower than the jamb sticker to get even chalk results. Just have to remember to bump the pressures up a bit when I’m towing or hauling any substantial weight.



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