Over inflate tires when towing?

[Olotti]

Originally Posted by MR.M

yes you need to increase the psi on your truck tire when hitched up and towing 35.psi won't do it . try 65 and go from there as far as ride and handling when towing

Thank you. 4 pages later and this is finally the answer I was looking for.

[Olotti]

Originally Posted by DieselDrax

So, your factory P-metric tires were rated for ~2500LB @ 35psi. To get that with your new LT tires, load range E, load index 123 (single tire), you'd need to run 50-55psi. 50psi = 2,470LB and 55psi = 2,625LB load capacity per tire.

At 35psi those tires have a load capacity of 1,910LB per tire.

Thank you for the reply. I will def go fill em up and see how the truck handles. I've noticed the ride is just squishy and my mpg has suffered.

[MR.M]

Originally Posted by Olotti

Thank you. 4 pages later and this is finally the answer I was looking for.

you're welcome . you'll get it dialed for you towing weight . i would rather be slightly over on psi then under .

[jtesta1]

Why would you want to over inflate your tires. You should have tires capable of supporting the legal weight of the vehicle. Over inflating your tires is putting undo stress upon them. I bet you're the kid who kept blowing up the balloons till they popped.

[MR.M]

Originally Posted by jtesta1

Why would you want to over inflate your tires. You should have tires capable of supporting the legal weight of the vehicle. Over inflating your tires is putting undo stress upon them. I bet you're the kid who kept blowing up the balloons till they popped.

who said anything about over inflating the tires ??? op stated the tires he has are rated for 80 psi . maybe you should read posts before making a comment .

[transmission_doctor]

Originally Posted by jackhartjr

The sidewalk of the tire gives the recommended pressure.

WRONG WRONG WRONG!

The pressure on the sidewall is the maximum pressure permitted for that tire. It is NOT the correct pressure for the load that is being carried. You will find the recommended pressure for the vehicles rated load on a sticker that the vehicle manufacturer provides, usually on a door panel

[TheWolfPaq82]

GMC must be the oddball. My Sierra 2500HD Diesel, the tires are 60 psi front and 70 psi rear.

[nomad297]

Originally Posted by MR.M

who said anything about over inflating the tires ??

I think that maybe he got the idea from the title of the thread and the original post.



Bruce

[Tireman9]

Originally Posted by Olotti

Is it common practice to overinflate the tires of the tow vehicle when towing. I just noticed the other day when my tt was hooked up and it is still dry as we just got it out of storage my tires were looking pretty squishy. Their 1 yr old Michelin AT2’s that are properly inflated to normal everyday driving. Where would I find the max psi to fill the tires? I assume on the tire and I’m guessing this will help with control and gas mileage.

Your tow vehicle ( truck) has a sticker on driver's door jam, just as all cars have had for the past 17+ years. These stickers AKA "Tire placard" or AKA "Vehicle certification labels" should have tire size and recommended tire inflation from the vehicle mfg. Some stickers also provide GVWR and GAWR.
Many trucks will have: LightLoad" and "Heavy or Full load" inflation numbers. The loaded numbers are what you should use when hooked up for towing. Both your truck dealer and your RV dealer have failed to do a basic part of their job of informing you and explaining this important safety information.


Your Trailer also has a sticker on the driver side outside toward the front. It also has tire size and MINIMUM inflation as well as the max GVWR and MAX GAWR. On many but not all trailers, the inflation on the sticker is the same as the inflation molded on the tire sidewall that is associated with the maximum tire load capacity.


All these inflations are measured when the tires are at ambient temperature which means not having been driven on or in direct sunlight for the previous 2 to 3 hours.


I have dozens of posts on my blog on inflation, loading and the labels. You might take a look to learn what your salespeople failed to educate you on.


Also you might review THIS post on tire failure.

[DouglasReid]

Originally Posted by TheWolfPaq82

I have two stickers on the sides of the frame with the Max psi recommended for the trailer. Mine run 65 psi.

Those would be for the tires supplied by the manufacturer at the time they built it.

The correct rating for the tires that are on there now will always be found on the sidewall of the tires.

Who do you believe knows more about the tires and their design, materials and ultimately their performance, Forest River or the Tire Manufacturer?

If you said The Tire Manufacturer you win the $64,201 grand prize!

[MR.M]

first off can't assume FR decides on tire pressure . they list the max cold inflation on their sticker for the tires they put on it . no where does FR state otherwise to my knowledge . if you go up in rating from a D to E the 65 psi is no longer valid . then you can look at charts and chose for yourself up to max cold inflation .

[5picker]

Originally Posted by transmission_doctor

WRONG WRONG WRONG!

The pressure on the sidewall is the maximum pressure permitted for that tire. It is NOT the correct pressure for the load that is being carried. You will find the recommended pressure for the vehicles rated load on a sticker that the vehicle manufacturer provides, usually on a door panel

ONLY ONLY ONLY! if the tires on the vehicle exactly match those which came on it from the factory.

In this case, the OP has admitted the tires have been replaced and with LT tires at that.

Saying tire pressures on the door panel are to be used for the replaced tires (being asked about in this thread) has no relevance to the discussion.

[D W]

Great conversation!

[DieselDrax]

Originally Posted by DouglasReid

Those would be for the tires supplied by the manufacturer at the time they built it.

The correct rating for the tires that are on there now will always be found on the sidewall of the tires.

Who do you believe knows more about the tires and their design, materials and ultimately their performance, Forest River or the Tire Manufacturer?

If you said The Tire Manufacturer you win the $64,201 grand prize!

The sidewall pressure is ONLY for max load. Not ALL loads. This is getting ridiculous.

[NMWildcat]

Originally Posted by DieselDrax

The sidewall pressure is ONLY for max load. Not ALL loads. This is getting ridiculous.

I agree with that if we are talking about TVs or motorhomes. If we are talking towables, I always will advise to run max cold psi. Why wouldn't you? Maybe if you are running tires with twice the load rating of oem, so you don't want to wear the middle of the tire out?

[Blackrock]

Originally Posted by DieselDrax

The sidewall pressure is ONLY for max load. Not ALL loads. This is getting ridiculous.

[ppine]

Never overinflate tires unless you want them to blow up.
Use a good weight distribution hitch and adjust it correctly to take some weight off the rear axle of your TV.

[myredracer]

Originally Posted by Olotti

Is it common practice to overinflate the tires of the tow vehicle when towing. I just noticed the other day when my tt was hooked up and it is still dry as we just got it out of storage my tires were looking pretty squishy. Their 1 yr old Michelin AT2’s that are properly inflated to normal everyday driving. Where would I find the max psi to fill the tires? I assume on the tire and I’m guessing this will help with control and gas mileage.

Did you say what you are towing somewhere?

We tow a 29' TT with an F250 with LRE tires. In the beginning when I went through the setup of the Reese DC WDH, I ended up finding 75 psi on the front and 80 on the rear provided the optimal handling and sway control. The only time I run lower psi is over the winter when the TT doesn't get used. I know of others who have found the higher TV pressures work better. I do NOT find that the higher pressures provide a harsher uncomfortable ride.

We have zero sway on interstates (at max. 65 mph) and the handling on twisty roads is great. If higher (cold) psi on the TV tires works better (as long as under sidewall max.) why not?

I think OP meant increase the tire pressure, not over-inflate them above the sidewall max.

[Airdale]

Originally Posted by Olotti

Thank you for the reply. I will def go fill em up and see how the truck handles. I've noticed the ride is just squishy and my mpg has suffered.

You've received a lot of misinformation up to this point and I'm going to try and solve some of it.

After reading all of your posts it's quite evident that your truck's Original Equipment (OE) tires were/have been replaced with "plus sized" tires. There are standard procedures for resetting the recommended inflation pressures for plus sized tires; the first of them is to ensure the new tires have the capability to provide a load capacity - via inflation pressures - equal to or greater than what the OE tires provided. To do that the installer will look at the tire placard and - using the proper load inflation chart for those tires - determine the load capacity they provide. Because the truck's OE tires were Passenger (P) tires it's a little more complicated because the truck manufacturer had to derate them by about 10% for service on your truck. In any event, a savvy installer will know the procedure.

I've not seen light trucks with more than one tire placard when equipped with OE passenger tires. So, when the plus sized tires are installed the new recommended cold inflation pressures will need to be set to insure they can carry the load capacity the OE tires were set to carry. Notations should be made in the vehicle owner's manual as to tire size and minimum recommended inflation pressures. Auxiliary (hand made) tire placards are allowed by NHTSA and can be placed adjacent to the original placards.

Remember these parameters; correct inflation is what has been recommended by the vehicle manufacturer. Optional inflation pressures are anything in between recommended cold and tire sidewall max. Over inflation is anything above cold sidewall max.

[Airdale]

Originally Posted by MR.M

first off can't assume FR decides on tire pressure . they list the max cold inflation on their sticker for the tires they put on it . no where does FR state otherwise to my knowledge . if you go up in rating from a D to E the 65 psi is no longer valid . then you can look at charts and chose for yourself up to max cold inflation .

From Forest River's standpoint your statement is very argumentative.

According to federal regulations, the vehicle manufacturer is the only one allowed to set inflation pressures for Original Equipment tires. (Excerpt from the regulation; "S5.3.1 Tires. The size designation and the recommended cold inflation pressure for those tires such that the sum of the load ratings of the tires on each axle is appropriate for the GAWR.")

When going from ST225/75R15 LRD to LRE an identical load inflation chart is used. Both LRD and LRE tires provide the same load capacity at 65 PSI.