Tire air psi- BFG A/Ts recommendation

[markusaf81]

What do you have?

Hmm, I dunno what the deal is, then. Even when I was running my 8 ply BFGs at 39 psi, I could definitely tell a difference in increased ride stiffness after I went from the stock SRA’s to those. Bumping them up to the recommended 55 psi helped as far as responsiveness, braking and cornering but damn, that’s when they really felt like a solid rubber tire with no give at all, whatsoever.


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Nitto Terra Grapplers. If they are at 39, they look like they are flat...looks like I have the whole truck loaded down. around 55 gives me a good ride and I leave them there even when I tow and stuff.

 

[corneileous]

Nitto Terra Grapplers. If they are at 39, they look like they are flat...looks like I have the whole truck loaded down. around 55 gives me a good ride and I leave them there even when I tow and stuff.

Hmm. Maybe it’s just me but that just seems awful odd to me that a 10 ply tire would look like it was flat at 39 psi and that if would need that much pressure to look as tho it had enough air in it.

My 8 ply BFG’s didn’t even change shape when I raised them from 39 to 55. When they were initially set to 39, they didn’t have a whole lot of sidewall bulge at all. Even the front. In other words, they didn’t look underinflated at all, not even a little bit. That’s why I was so at an awe when that BFG guy said I was like at dangerous levels running those tires at that pressure. They didn’t even build a whole lot of pressure when you drove down the highway even. They’d average out at about 43, 44 psi.


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[markusaf81]

Hmm. Maybe it’s just me but that just seems awful odd to me that a 10 ply tire would look like it was flat at 39 psi and that if would need that much pressure to look as tho it had enough air in it.

My 8 ply BFG’s didn’t even change shape when I raised them from 39 to 55. When they were initially set to 39, they didn’t have a whole lot of sidewall bulge at all. Even the front. In other words, they didn’t look underinflated at all, not even a little bit. That’s why I was so at an awe when that BFG guy said I was like at dangerous levels running those tires at that pressure. They didn’t even build a whole lot of pressure when you drove down the highway even. They’d average out at about 43, 44 psi.


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different tires, different construction, different load ratings. From what ive heard, the nittos are softer then the KO2's so that would explain stuff. Plus, keep in mind that the tire is going to be different in motion then just sitting still on pavement.

Nittos website specifically states NOT to use recommended air pressure if original size is not used...contact manufacturer. When Ram put those stickers on, they just got the air pressure from Goodyear.

 

[markusaf81]

Hmm. Maybe it’s just me but that just seems awful odd to me that a 10 ply tire would look like it was flat at 39 psi and that if would need that much pressure to look as tho it had enough air in it.

My 8 ply BFG’s didn’t even change shape when I raised them from 39 to 55. When they were initially set to 39, they didn’t have a whole lot of sidewall bulge at all. Even the front. In other words, they didn’t look underinflated at all, not even a little bit. That’s why I was so at an awe when that BFG guy said I was like at dangerous levels running those tires at that pressure. They didn’t even build a whole lot of pressure when you drove down the highway even. They’d average out at about 43, 44 psi.


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Also, if the tire PSI range is 0-80 and you are airing it from 34 to 55, you should see a slight change...not going to be much I don't think depending on sidewall dimensions. I didn't see what size rim you were running. A 35 inch tire on a 17 inch rim is going to show a lot of change but a 34 inch tire on a 20 inch rim wont show much

 

[corneileous]

different tires, different construction, different load ratings. From what ive heard, the nittos are softer then the KO2's so that would explain stuff. Plus, keep in mind that the tire is going to be different in motion then just sitting still on pavement.

What load rating are those? My BFG’s being a load range D are 3000 max weight rating at 65psi.

Nittos website specifically states NOT to use recommended air pressure if original size is not used...contact manufacturer. When Ram put those stickers on, they just got the air pressure from Goodyear.

Do they have any info on their site about what pressures to run?

Yeah I figured the factory pressure recommendation was set specifically for the tires slapped on at the factory.

I never thought about whether or not I’d have to adjust pressures primarily because I was staying with the factory size. But, as I stated long time ago in the discussion, I didn’t know these BFG’s where an 8 ply tire and that those stock SRA’s where a standard load, passenger rated tire of things.




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[markusaf81]

What load rating are those? My BFG’s being a load range D are 3000 max weight rating at 65psi.


Do they have any info on their site about what pressures to run?

Yeah I figured the factory pressure recommendation was set specifically for the tires slapped on at the factory.

I never thought about whether or not I’d have to adjust pressures primarily because I was staying with the factory size. But, as I stated long time ago in the discussion, I didn’t know these BFG’s where an 8 ply tire and that those stock SRA’s where a standard load, passenger rated tire of things.




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Lol, I just read their "tires 101" and that's where I read "contact Nitto for specific tire pressure." So I just contacted them, curious to see what they tell me.

I think my load rating was E but not sure and my truck is in the shop so I cant look....could've sworn they were 3200 nax weight

 

[corneileous]

Lol, I just read their "tires 101" and that's where I read "contact Nitto for specific tire pressure." So I just contacted them, curious to see what they tell me.

I think my load rating was E but not sure and my truck is in the shop so I cant look....could've sworn they were 3200 nax weight

Do you remember what the max inflation on them is? Usually on a 10 ply, load range E tire, it’s 80 psi.

What size are they again?


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[markusaf81]

Do you remember what the max inflation on them is? Usually on a 10 ply, load range E tire, it’s 80 psi.

What size are they again?


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LT275/65/20. I think that's a 34x11 or close. Max inflate was 80psi

 

[markusaf81]

Do you remember what the max inflation on them is? Usually on a 10 ply, load range E tire, it’s 80 psi.

What size are they again?


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56lbs, 80psi max inflate, 3750 Load, 34.1x10.98, 126/123S, Load E

 

[Gary2]

In the rear I only run 33lbs. Beds always empty and its a reg cab short bed. I'd go lower if it werent for the damn TPMS. Winter sucks for me if I leave it outside as the cold temps drops the pressure so much then the damn lights on , back to 39lbs to reset and then start over again. Jeep sleeps in the garage mostly being I am always changing things on it and being retired there is no telling what time I will be tinkering. Going to be putting these tires and wheels on a buddys truck to see if the vibes follow it . If so these will get canned and I will have 17"

 

[yortnodnarb]

I'm sure the manufacturer's tech department is covering their tail a little with the 50+psi recommendation. But at some point you have to put a little trust in somebody, and following somebodies shade tree science isn't going to be where I place my trust.

 

[corneileous]

In the rear I only run 33lbs. Beds always empty and its a reg cab short bed. I'd go lower if it werent for the damn TPMS. Winter sucks for me if I leave it outside as the cold temps drops the pressure so much then the damn lights on , back to 39lbs to reset and then start over again. Jeep sleeps in the garage mostly being I am always changing things on it and being retired there is no telling what time I will be tinkering. Going to be putting these tires and wheels on a buddys truck to see if the vibes follow it . If so these will get canned and I will have 17"

What do you run in the front? I’m gonna have to try it a few more days to fully experiment with it but I think I like mine at 45 in the front and 40 in the back. Seems alright there, for now.


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[corneileous]

I'm sure the manufacturer's tech department is covering their tail a little with the 50+psi recommendation. But at some point you have to put a little trust in somebody, and following somebodies shade tree science isn't going to be where I place my trust.

I hear ya.

I’m still pretty much convinced that I could safely get away with running these tires at 39 psi all the way around and be just perfectly fine.

If you go off the logic that at 65 psi, my tires will support 3000 pounds a piece so at 33 psi, they oughta safely support at least 1500 pounds per tire, shouldn’t they? I highly doubt my truck weighs more than 6000 pounds and even at that, that’s what, 4000 pounds bearing down on the front axle and maybe 2 grand on the back axle? I don’t know how to do the math but at least on the front, 39 should be plenty.


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[Gary2]

What do you run in the front? I’m gonna have to try it a few more days to fully experiment with it but I think I like mine at 45 in the front and 40 in the back. Seems alright there, for now.


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fronts are between 35-37

 

[corneileous]

fronts are between 35-37

Damn. Yeah, I had to scroll back up a little to see that you were running the 35’s.

Yeah, I think if I was ever to decide I wanted 35’s on my half-ton, they wouldn’t be on that big of a rim. I’d go down in rim size as much as I could to stay away from a 10 ply tire, but still be big enough to not have clearance issues on the brake calipers.


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[yortnodnarb]

I hear ya.

I’m still pretty much convinced that I could safely get away with running these tires at 39 psi all the way around and be just perfectly fine.

If you go off the logic that at 65 psi, my tires will support 3000 pounds a piece so at 33 psi, they oughta safely support at least 1500 pounds per tire, shouldn’t they? I highly doubt my truck weighs more than 6000 pounds and even at that, that’s what, 4000 pounds bearing down on the front axle and maybe 2 grand on the back axle? I don’t know how to do the math but at least on the front, 39 should be plenty.


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Scratch that, I quit.

 

[corneileous]

Scratch that, I quit.

Lol, what?

I was gonna say so, based on that logic, 39psi, or even what I have them at now- 45 front, 40 rear- should be plenty for being considered fully loaded?


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[AJAY]

When I run my Toyos ATII in LT276/65r20 I run 44psi in the front and 41psi in the rear and the wear is even. And 47psi in the rear when I tow or haul heavy. Smooth ride.

Also for my T/G Max in LT305/70r18 I run 43psi and 41psi in the rear. They ride softer then my 20s lol

 

[corneileous]

Well so far I think I’m pretty happy with running 45 on the steer axle and 40 or 41 on the drive axle.


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[Gary2]

I have been chasing a high speed vibe in my truck since Mavis installed them a year and a half ago . I also noticed when I hit small bumps in the road it felt like the tire may of been shaking kind of like Jello so to speak . It felt almost like the shocks were worn but I know they were new also. I have never had old shocks on the truck as long as I owned it . I got to thinking , was the extra shake due to low air pressure so I decided to go up to like 42 and noticed a slight improvement at lower speeds on rough roads. Then I remembered this thread mentioning 55lbs. So for the hell of it I went to 48 front 44psi rear and my high speed vibe was much reduced. I also noticed I could hear the tires making a creaking sound as I approached 48psi almost like the threads were being stretched or something. The ride is very much improved overall . It is not a harsh ride as the OE tires with OE shocks were at 39psi. I guess the Bilstein's are a better shock for these tires and seems to handle the tires better the the OE set up did with OE tires. That is what steered me to the lower psi as that was the only way to get the OE set up near civilized ride wise. I have always sold the OE 20s on every ram and replaced them with 17" 35s and never had or needed 10 ply tires either. This 20" BS is a new animal for me and still regret staying with 20s but I can't afford to throw them away. I would say if you have 35-12.50-20 KO2s and good aftermarket shocks give it a try. My ride is improved but still not quite what my last 4 Rams were with 17s was. This truck will most likely get traded in soon anyway as the novalty has pretty well worn off after all this, even if it was some what self inflicted .