Ok, so I just picked up some new 245/75/16 BFG Long Trail TA Tours from an online site with free shipping. I also got a $70 rebate bringing the price to $340 for the total deal. I'm going to have them mounted on my Double Cab Tacoma and just noticed the max PSI is 80. according to the sidewall. My truck has 29 PSI listed on the door jam. I'm thinking somewhere in the middle close to 40 psi. What do you guys think???
Sidewall Pressure or Door Jam
- Thread starter Badlees
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I never know what to do in similar situations.....
I usually just compromise.
I usually just compromise.
The sidewall lists the maximum pressure, not the recommended operating pressure.
For passenger car tires this is sometimes the pressure needed to support the maximum rated tire load, but this need not be the case.
You should use the pressure on the door jam as the starting point, and not vary too much from the recommendation. Certainly 40psi is too high -- that much pressure will increase NVH and decrease the contact patch.
For passenger car tires this is sometimes the pressure needed to support the maximum rated tire load, but this need not be the case.
You should use the pressure on the door jam as the starting point, and not vary too much from the recommendation. Certainly 40psi is too high -- that much pressure will increase NVH and decrease the contact patch.
Does the truck only list a single PSI, regardless of carrying weight? What about your owner's manual?
29 PSI may be fine for an empty truck, but once you carry heavy load, more may be needed. Also, check the tire's sidewall at what PSI it achieves its max load rating as it's probably different from max PSI.
29 PSI may be fine for an empty truck, but once you carry heavy load, more may be needed. Also, check the tire's sidewall at what PSI it achieves its max load rating as it's probably different from max PSI.
I will check it tonight but I'm fairly sure the sidewall MAX PSI is 80. I would think that 29 PSI would almost buckle the tire in the middle. That seems a little low. I bet I could go 32 all around but I do tow a boat. It's not very heavy, maybe 2500 lbs.
Originally Posted By: Badlees
I will check it tonight but I'm fairly sure the sidewall MAX PSI is 80.
I don't question that. I am just saying that there may be another PSI figure given on the sidewall if you look carefully. This other figure is the PSI at which the tire reaches max load index.
I will check it tonight but I'm fairly sure the sidewall MAX PSI is 80.
I don't question that. I am just saying that there may be another PSI figure given on the sidewall if you look carefully. This other figure is the PSI at which the tire reaches max load index.
Just an anecdote. I have an 01 Tacoma Prerunner Ext cab. I have Uniroyal Laredo's which have worn well. IIRC, they too are about 29 PSI, I usually run about 2-3lbs psi above the recommended. If I get much higher it seems to make for a harsh ride.
But, if you carry frequently carry a load that might be less a factor.
Sounds like you got in on the Discount Tire Direct promo offer.
But, if you carry frequently carry a load that might be less a factor.
Sounds like you got in on the Discount Tire Direct promo offer.
FYI, according to the tire's manufacturer, max load is achieved at 44 PSI:
http://www.bfgoodrichtires.com/specs/long-trail-t-a-tour/3932.html
http://www.bfgoodrichtires.com/specs/long-trail-t-a-tour/3932.html
JHZR2
Staff member
Most people find that the OE pressures are set for ride comfort, and they get better overall characteristics by upping the pressure a bit. Sometimes the handling can be slightly changed for the worse or better by varying the pressure in front or rear a bit.
Hypermilers often inflate to sidewall max pressure. It will effect ride quality a bit, but often they find that by driving gently, they still maximize tire life by tens of thousands of miles.
29 psi doesn't sound like it is designed for full load. Is there only one pressure recommended?
Hypermilers often inflate to sidewall max pressure. It will effect ride quality a bit, but often they find that by driving gently, they still maximize tire life by tens of thousands of miles.
29 psi doesn't sound like it is designed for full load. Is there only one pressure recommended?
::Look - Up in the sky!!::
Is it a bird? Is it a plane?
No, it's TIREMAN! Strange visiter who lives eats and breathes TIRES. Who knows what a sidewall says without actually looking at it. And who will sometimes clear up many misconceptions about tires - which he is about to do now::
Badlees:
You picked up LT245/75R16 Load Range E tires - a very common size for heavy duty pickup trucks - F-350's and C/K3500's. They are indeed 80 psi tires.
However the placard on your truck calls for P245/75R16's. These are 2 different animals! Let me give you an example.
At 35 psi, a P245/75R16 is rated for 2271#, but since it is being used on a pickup truck, it has to be derated 10% = 2065#
An LT245/75R16 at 35 pai has a load carrying capacity of 1700# - and it doesn't need to be adjusted because it was designed for use on trucks.
What's this mean?
That if the placard calls for 29 psi for a P245/75R16, in order to get the same load carrying capacity, an LT245/75R16 needs to use 38 psi.
Is it a bird? Is it a plane?
No, it's TIREMAN! Strange visiter who lives eats and breathes TIRES. Who knows what a sidewall says without actually looking at it. And who will sometimes clear up many misconceptions about tires - which he is about to do now::
Badlees:
You picked up LT245/75R16 Load Range E tires - a very common size for heavy duty pickup trucks - F-350's and C/K3500's. They are indeed 80 psi tires.
However the placard on your truck calls for P245/75R16's. These are 2 different animals! Let me give you an example.
At 35 psi, a P245/75R16 is rated for 2271#, but since it is being used on a pickup truck, it has to be derated 10% = 2065#
An LT245/75R16 at 35 pai has a load carrying capacity of 1700# - and it doesn't need to be adjusted because it was designed for use on trucks.
What's this mean?
That if the placard calls for 29 psi for a P245/75R16, in order to get the same load carrying capacity, an LT245/75R16 needs to use 38 psi.
Originally Posted By: CapriRacer
::Look - Up in the sky!!::
Is it a bird? Is it a plane?
No, it's TIREMAN! Strange visiter who lives eats and breathes TIRES. Who knows what a sidewall says without actually looking at it. And who will sometimes clear up many misconceptions about tires - which he is about to do now::
Badlees:
You picked up LT245/75R16 Load Range E tires - a very common size for heavy duty pickup trucks - F-350's and C/K3500's. They are indeed 80 psi tires.
However the placard on your truck calls for P245/75R16's. These are 2 different animals! Let me give you an example.
At 35 psi, a P245/75R16 is rated for 2271#, but since it is being used on a pickup truck, it has to be derated 10% = 2065#
An LT245/75R16 at 35 pai has a load carrying capacity of 1700# - and it doesn't need to be adjusted because it was designed for use on trucks.
What's this mean?
That if the placard calls for 29 psi for a P245/75R16, in order to get the same load carrying capacity, an LT245/75R16 needs to use 38 psi.
Thanks TIREMAN! You're my hero! LOL 38 PSI it shall be.
::Look - Up in the sky!!::
Is it a bird? Is it a plane?
No, it's TIREMAN! Strange visiter who lives eats and breathes TIRES. Who knows what a sidewall says without actually looking at it. And who will sometimes clear up many misconceptions about tires - which he is about to do now::
Badlees:
You picked up LT245/75R16 Load Range E tires - a very common size for heavy duty pickup trucks - F-350's and C/K3500's. They are indeed 80 psi tires.
However the placard on your truck calls for P245/75R16's. These are 2 different animals! Let me give you an example.
At 35 psi, a P245/75R16 is rated for 2271#, but since it is being used on a pickup truck, it has to be derated 10% = 2065#
An LT245/75R16 at 35 pai has a load carrying capacity of 1700# - and it doesn't need to be adjusted because it was designed for use on trucks.
What's this mean?
That if the placard calls for 29 psi for a P245/75R16, in order to get the same load carrying capacity, an LT245/75R16 needs to use 38 psi.
Thanks TIREMAN! You're my hero! LOL 38 PSI it shall be.
CAUTION! If this is an LT tire as opposed to a P rated tire, then higher air pressure is required for the same load to be carried. Failure to run that extra pressure in an LT tire can cause significant overheating and sidewall failures!
http://www.nittotire.com/assets/safety/Replacing Tires on Light Trucks.pdf
Please llok at the temperature photos of the tires. I see too many people replacing P tires with LT and running 30 psi like they were P tires. But the load carrying ability is REDUCED at that pressure and heat buildup is INCREASED!
http://www.nittotire.com/assets/safety/Replacing Tires on Light Trucks.pdf
Please llok at the temperature photos of the tires. I see too many people replacing P tires with LT and running 30 psi like they were P tires. But the load carrying ability is REDUCED at that pressure and heat buildup is INCREASED!
That seems counter-intuitive. I'm not arguing that it's wrong, just questioning why. To the casual observer, the LT tires are "stronger" or "tougher", or at least marketed as such.
So why do they require more air to achieve the same load capacity?
So why do they require more air to achieve the same load capacity?
Originally Posted By: Jason Adcock
That seems counter-intuitive. I'm not arguing that it's wrong, just questioning why. To the casual observer, the LT tires are "stronger" or "tougher", or at least marketed as such.
So why do they require more air to achieve the same load capacity?
Basically it's this:
While the rubber in LT tires is stronger and capable of handling more unit load (load per volume), the result is a rubber that has less ability to flex. So while a passenger car tire's rubber is OK with a certain amount of deflection, an LT's rubber is more prone to failure under the same amount of deflection - so more inflation pressure to get less flexing.
That seems counter-intuitive. I'm not arguing that it's wrong, just questioning why. To the casual observer, the LT tires are "stronger" or "tougher", or at least marketed as such.
So why do they require more air to achieve the same load capacity?
Basically it's this:
While the rubber in LT tires is stronger and capable of handling more unit load (load per volume), the result is a rubber that has less ability to flex. So while a passenger car tire's rubber is OK with a certain amount of deflection, an LT's rubber is more prone to failure under the same amount of deflection - so more inflation pressure to get less flexing.
Originally Posted By: CapriRacer
While the rubber in LT tires is stronger and capable of handling more unit load (load per volume), the result is a rubber that has less ability to flex. So while a passenger car tire's rubber is OK with a certain amount of deflection, an LT's rubber is more prone to failure under the same amount of deflection - so more inflation pressure to get less flexing.
Excellent reply, thanks!
While the rubber in LT tires is stronger and capable of handling more unit load (load per volume), the result is a rubber that has less ability to flex. So while a passenger car tire's rubber is OK with a certain amount of deflection, an LT's rubber is more prone to failure under the same amount of deflection - so more inflation pressure to get less flexing.
Excellent reply, thanks!
And as the Nitto heat photos show in the link above, allowing that flexing to occur in an LT tire can result in potentially catastrophic heating. I personally have seen several LT tires used as replacements and run at 30 psi like they were P rated tires where the sidewalls split at about 20,000 miles! So you need to beware. You don't need to haul loads to generate excessive heat in LT tires that are inflated like P rated tires!
LT tires sound like a real winner in a compact pickup... Load capacity one will never see, worsened ability to absorb shock and overall rougher ride.
Why don't they just get rid of the LT designation, and use something else instead to get rid of the confusion.
Why don't they just get rid of the LT designation, and use something else instead to get rid of the confusion.
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