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Technically speaking, it depends on a lot of things. But getting your psi correct is very important as if effects the tire carrying capacity under load and the contact patch or traction ability of the tire.

Brand/tire model - different brands have different specs and load capabilities
Load range - C, D, E, ect
Size - 35x12.50r17 or 315/70r17 (both are considered 35's)

But honestly, you'll probably be alright adding 5-10 psi. I work in the tire industry and can give you the technical number if you give me the specs on your tire. In my shop, if we are over sizing tires and as long as the load rating is equal to or higher, we usually add 5-10 psi but technically it does depend on many different variables.

Let me know if I can be of any more help!
 

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Discussion Starter · #3 ·
@lmeavtitn.


My tires are bfgoodrich KO2 @ 315/70/17 Rated E
My old tire were the stock tire which i believe were 275/70/17 and had 55 PSI front and 45 PSI rear ( its marked in the door)
 

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@lmeavtitn.


My tires are bfgoodrich KO2 @ 315/70/17 Rated E
My old tire were the stock tire which i believe were 275/70/17 and had 55 PSI front and 45 PSI rear ( its marked in the door)
The psi marked on the door placard is only for the size that came with the vehicle. When you alter Tire size, you have to alter the psi. An example of this is a 1500 which came with P rated tires from the factory. The psi on the sticker might say 35. If someone goes up to an LT Tire it would require a higher psi to handle the same load. The same is true with altering the sizes.
 

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BFG rates that tire for max 3195 lb load at 65 psi. I clipped the appropriate line from BFG's specs (see below). I wasn't able to find their inflation tables, which would give a good range, but here's a rough guide: Typically dropping the load by 10% would result in a recommended inflation level drop of about 10 psi, for tires in this general range.

Ram recommends 55 psi on the Toyos, and from the Toyo inflation/load tables, that means Ram is estimating a load value of 2900 lbs. That's about 300 lbs lower than the 3195 (3200) max that BFG rates the K02 for in this size. That's about a 10% drop in load. So it would seem appropriate to run them at about 55psi.

Now if you do find an actual BFG full load table that gives different loads and inflations for the same tire, you might get a more accurate recommendation, maybe 56 instead of 55, for example.
 

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Technically speaking, it depends on a lot of things. But getting your psi correct is very important as if effects the tire carrying capacity under load and the contact patch or traction ability of the tire.

Brand/tire model - different brands have different specs and load capabilities
Load range - C, D, E, ect
Size - 35x12.50r17 or 315/70r17 (both are considered 35's)

But honestly, you'll probably be alright adding 5-10 psi. I work in the tire industry and can give you the technical number if you give me the specs on your tire. In my shop, if we are over sizing tires and as long as the load rating is equal to or higher, we usually add 5-10 psi but technically it does depend on many different variables.

Let me know if I can be of any more help!


Hello, think i made a mistake... I mounted today LT315/70/17 duratrac. Love them but....load D. Side walls say max cold psi 50. The darn tpms light comes on it they are below the 55 front and 45 rear. Tire place had them at 39psi. Are there any work arounds or i wonder if there is a sweet spot near the 50 that won't make the light come. Also had a diablo tuner but there was no function for lower the tpms threshold/only changed the tire size.(on my ram 1500 2014 sport)
Man these ride like riding on air compared to the Toyo's. They are a bit noisy compared though.
 

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The Duratrac, according to Goodyear's specs, is rated for 3195 lbs load at 50psi, which is also its max. Dropping to Ram's 2900 lb load target would put you in the 44.5 - 45.5 psi range, if you plan to follow all the tire/vehicle mfr guidelines.
 

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Hello, think i made a mistake... I mounted today LT315/70/17 duratrac. Love them but....load D. Side walls say max cold psi 50. The darn tpms light comes on it they are below the 55 front and 45 rear. Tire place had them at 39psi. Are there any work arounds or i wonder if there is a sweet spot near the 50 that won't make the light come. Also had a diablo tuner but there was no function for lower the tpms threshold/only changed the tire size.(on my ram 1500 2014 sport)
Man these ride like riding on air compared to the Toyo's. They are a bit noisy compared though.
No way around the TPMS unfortunately. That is a factory set component. They are going to be noisier as they have bigger voids between the tread blocks.

Does the TPMS light turn on at 50 psi? I want to say that on my truck, one of my tires leaked and I caught it at 50 on the RF but my TPMS light was not illuminated on the dash - I just saw it by going through the EVIC and seeing the individual tire psi.
 

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I think I am good. Backs fine at 45psi front cold I did 48 and no alarm. I think they are 4 pounds heavier from the Toyos. Man the feel difffernent. You can feel them. Time will tell if I will end up liking them. We had rain today and wow, they really kept great traction.
Thanks Imeavititn
 

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I think I am good. Backs fine at 45psi front cold I did 48 and no alarm. I think they are 4 pounds heavier from the Toyos. Man the feel difffernent. You can feel them. Time will tell if I will end up liking them. We had rain today and wow, they really kept great traction.
Thanks Imeavititn
No problem!
 

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Hello, think i made a mistake... I mounted today LT315/70/17 duratrac. Love them but....load D. Side walls say max cold psi 50. The darn tpms light comes on it they are below the 55 front and 45 rear. Tire place had them at 39psi. Are there any work arounds or i wonder if there is a sweet spot near the 50 that won't make the light come. Also had a diablo tuner but there was no function for lower the tpms threshold/only changed the tire size.(on my ram 1500 2014 sport)
Man these ride like riding on air compared to the Toyo's. They are a bit noisy compared though.
They may seem like riding on air due to being under inflated for the truck?
 

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Lol, you got it.... 50 psi prob riding on the rim. Air so low the tire may come off.:nerd:

Funny....

I went with Nitto Terra Grappler G2's in a 315 size. I really like them a lot. I found about five lbs. over the stock tire pressure rides very well but 8 lbs. feels like the suspension is not happy with the combination.
 
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