Do you increase tire pressure when towing?

[lbrjet]

You wrote a lot of words but failed to answer the question.

[SidecarFlip]

Originally Posted by lbrjet

You wrote a lot of words but failed to answer the question.

Engineers and politicians...write a lot, say little.....

[Tireman9]

Originally Posted by lbrjet

You wrote a lot of words but failed to answer the question.

Sorry, for trying to provide the facts to help people understand. Intuition is no substitute for facts, data and science


Answer is
LR-E tires are not always thicker than LR-D tires

[lbrjet]

You already said that.

My specific example is same brand, size. That is why I am asking for an answer on my specific question. Not a generic answer. I get that thickness could change across different brands.

Seems like for the same brand and size there must be some difference between a D and E.

[Tireman9]

Originally Posted by lbrjet

You already said that.

My specific example is same brand, size. That is why I am asking for an answer on my specific question. Not a generic answer. I get that thickness could change across different brands.

Seems like for the same brand and size there must be some difference between a D and E.

I have not examined all brands or all sizes so don't know how to answer with all encompassing answer but if that is all you will accept here it is.

There are differences between LR-D and LR-E tires of same brand and same size in most but not all cases. Those differences, if they exist are not likely to be in thickness.


Here again are too many words

I understand you want a simple Yes or no answer but the reality is that there are many variables, Sometimes there are even LR-D and LR-E tires are identical except for letters molded on the sidewall and sometimes there are a number of material differences.

[PTaylor883]

Originally Posted by LJS1211

Last week I purchased new E rated tires for my F150. Went with the BF Goodrich KO2 (275/65/18) and so far I'm very happy with them. These are larger than the tires that came from the factory (265/60/18). I'm pulling my trailer for the first time this weekend so had a quick question.

The tire shop originally put the PSI at 35 based on the door sticker but after reaching about to BF Goodrich they suggested to bump it up to 45 for everyday driving. They were not able to give any recommendations for tire pressure while pulling a trailer since there are so many variables like trailer size, weight and cargo. The tire shop suggested going to 50 pounds and then deflating back down after the trip. I'm just curious if others actually bump up their PSI while towing and have you noticed a difference in doing this? Just trying to figure out if there is a benefit to doing this. Thanks in advance for your feedback.

I would agree with 2Evil4U to fill the tires to the OEM pressure, but if you install larger than OEM tires there are two consequences: 1) the max PSI of the new tires will be different than the door sticker and 2) the odometer will become inaccurate.

So, you are now in LaLa Land. I would go with max PSI on the tire sidewall, and try to estimate how much the odometer is off.

[PTaylor883]

Originally Posted by SidecarFlip

Engineers and politicians...write a lot, say little.....

Not nice Sidecar. Engineers, scientists, and mathematicians deserve respect, even if lay people can't understand them. It's not funny.

[goduc]

Originally Posted by lbrjet

Your number 3 is based on your opinion and not on any facts. The extra thickness of the tire may indeed not be waste of money if you pick up a screw and it would puncture a D, but not an E.

As for your number 4 the door jam pressure for the OEM tires on any car or truck will support the full GVWR. That is the whole point.

You left us hanging about what the major difference is on your number 2.

Only difference in thickness is zero. They all have 15/32 tread depth except one size thats not what the OP needs. Both the E and D are 15/32".

[lbrjet]

Not talking about tread depth. The entire thickness of the tire.

[Tireman9]

You guys are asking for the engineering reasons for changes in tire design but seem to want grade school answers. Sorry but tire design is more complicated than that. I suggest you watch the numerous videos on how tires are made, You might also want to review some of by blog posts so you would have a better understanding of the issues involved.

[Funhaus]

Originally Posted by goduc

Only difference in thickness is zero. They all have 15/32 tread depth except one size thats not what the OP needs. Both the E and D are 15/32".

Are you saying ALL Load range D and E tires have 15/32" tread depth?

[mac.dblues]

Originally Posted by LJS1211

Last week I purchased new E rated tires for my F150. Went with the BF Goodrich KO2 (275/65/18) and so far I'm very happy with them. These are larger than the tires that came from the factory (265/60/18). I'm pulling my trailer for the first time this weekend so had a quick question.

The tire shop originally put the PSI at 35 based on the door sticker but after reaching about to BF Goodrich they suggested to bump it up to 45 for everyday driving. They were not able to give any recommendations for tire pressure while pulling a trailer since there are so many variables like trailer size, weight and cargo. The tire shop suggested going to 50 pounds and then deflating back down after the trip. I'm just curious if others actually bump up their PSI while towing and have you noticed a difference in doing this? Just trying to figure out if there is a benefit to doing this. Thanks in advance for your feedback.

The door sticker is for the factory tires. As others suggested, I would run more air in the rear tires for towing, but it could require some trial and error. 50 psi may do well, but you should make a mental note of how the tire squats when under load and try to make it close to the same as unloaded at the 45 psi BFG suggested.

I have Nitto Trail Grappler M/T's in a LT295/70R18. I emailed Nitto when I had them installed and asked what pressure I should run to get the best ride/longest life combination. They replied with 37 psi so that is where I keep mine. The tire is rated for a little over 4000 lbs @ 80 psi, but there is no way I would run them at 80 psi. If I remember Friday, I am going to air them up to 60 psi to haul the trailer to camp and see how it does.

[2 in a Roo]

My 10 ply E Cooper tires are rated for 80 pounds max. I fill them to 70 pounds when towing, otherwise air down to 60 for an easier ride.

[2 in a Roo]

Originally Posted by TimVWulp

Hi I would not run a higher tire pressure than what is on the door sticker! :

Tim, that sticker has no clue to the type of tires on your truck.

[2 in a Roo]

Originally Posted by 2 in a Roo

Tim, that sticker has no clue to the type of tires on your truck.

I just went out and carefully read my sticker. It refers to the "original tires", not the tires I currently have on.

[Tireman9]

F150 probably came with P type tires as that vehicle is aimed and designed for more passenger like use.
F250 & F350 are designed to be used as trucks so come with LT type tires.


If you are using your F150 to tow than you need to learn the actual rear axle load when towing and when the trailer is full of stuff and the gas tank is full.
The scale at a truck stop will tell you the actual axle load.
1. You need to confirm you are not overloading the truck axle.
2. Knowing the actual towing load you can consult the Load-Infl tables to learn the minimum cold inflation to run in the rear tires. It is suggested you run at least that infl +10%

Of course your trailer tires of ST type should be inflated to the tire sidewall pressure when cold.

[Hersbird]

The load rating of an LT tire is proportional to the max pressure. So if it's rated to carry say 4400 pounds at 80 psi it will only carry 2200 pounds at 40 psi, even less at a normal P metric tire sticker recommendation of 35 psi. If you switch from P tires to LT tires and then keep them at the low pressure you probably have actually reduced load carrying ability of your tires compared to factory. They will also cause poor fuel economy. The only reason to run a LT tire that low is off road.

On the road I see no reason to run an LT tire under 60 psi, my truck is pretty much only used to tow or haul and i just keep the tires at 75-80.

[Tireman9]

Originally Posted by Hersbird

The load rating of an LT tire is proportional to the max pressure. So if it's rated to carry say 4400 pounds at 80 psi it will only carry 2200 pounds at 40 psi, even less at a normal P metric tire sticker recommendation of 35 psi. If you switch from P tires to LT tires and then keep them at the low pressure you probably have actually reduced load carrying ability of your tires compared to factory. They will also cause poor fuel economy. The only reason to run a LT tire that low is off road.

On the road I see no reason to run an LT tire under 60 psi, my truck is pretty much only used to tow or haul and i just keep the tires at 75-80.

Since the inflation pressure "P" is part of the tire load formula for all tires, yes the load capacity is proportional to the inflation BUT it is not directly proportional. i.e. cut the inflation in half does not cut the load capacity in half.
Also, the ratio is exponential as the P term has different exponents for different types tires i.e. p**.8 or P**.7 or P**.525

[mac.dblues]

Originally Posted by 2 in a Roo

I just went out and carefully read my sticker. It refers to the "original tires", not the tires I currently have on.

(Sorry, couldn't help myself.)

[Hersbird]

Originally Posted by Tireman9

Since the inflation pressure "P" is part of the tire load formula for all tires, yes the load capacity is proportional to the inflation BUT it is not directly proportional. i.e. cut the inflation in half does not cut the load capacity in half.
Also, the ratio is exponential as the P term has different exponents for different types tires i.e. p**.8 or P**.7 or P**.525

I meant P as in P-metric tires that come standard on most 1/2 tons compared to LT tires. I didn't even touch on how a standard load P-metric tire keeps it's load rating even from 36-44psi while a reinforced load P-metric will increase over that inflation range.

You are right though, I do see now on the tables it is linear but not at a 1:1 rate for LT tires.

Still, look at a common LT 275/65R17 is 3195 pounds at 80 psi and 2055 at 40, and only 1870 pounds at 35 psi!
The P 275/65R17 in just standard load is 2535 pounds at 35 psi
These are off Toyo tire's inflation tables for TRA tires.

So if your truck came with standard load P-metric tires and the door sticker says 35 psi, then you go to LT tires of the same size but don't increase the pressure you lose 665 pounds of carrying ability per tire or 2660 pounds total. Tires are often the limiting factor in payload ratings any now you have just lost it all.

PS, where does the LT tire in the example above match the load ability the P-metric tire? at 55 psi. Why I said run at least 60 if the point is to gain ability by using LT tires.