Tire psi

[Cfitzkp]

New to all this have a question about tire psi my truck says max 35 psi but heard to put more while towing can any body help me out on whats good...?

[KeithInUpstateNY]

That seems low for max pressure.

The tire and loading sticker on the door for my Goodyear Wranglers is 35 psi, but the max pressure on the tire sidewall is 350 kPa (51psi).

[SummitPond]

Chris

Others will chime in, but it would help if you listed the equipment (tire size, load rating, etc). Also your TT and TV. The latter can go in your signature area.

It is my understanding to never exceed cold rating on the sidewall; for some situations you may run lower pressures.

Question: Do the tires have load carrying capability? This is also on the sidewall.

[sourdough]

As summitpond mentioned, posting the numbers off the stickers inside the driver door of your tow vehicle and the numbers off the sticker on the driver side of the rv will tell you lots about what you need to know.

I'm assuming the 35psi recommended is the everyday, non towing recommendation. The info above, including the info on the sidewall of the tire (max pressure/load) will help and is something you need to know.

[Cfitzkp]

As summitpond mentioned, posting the numbers off the stickers inside the driver door of your tow vehicle and the numbers off the sticker on the driver side of the rv will tell you lots about what you need to know.

I'm assuming the 35psi recommended is the everyday, non towing recommendation. The info above, including the info on the sidewall of the tire (max pressure/load) will help and is something you need to know.

And the tire says 51psi

[Roscommon48]

interesting.. what the heck are you pulling anyway? i ca't image you can pull much with this vehicle.



stick with what the manufacture shows you.

[Logan X]

I think with the trailer you have, a premier 34bi if I’m not mistaken, you should have light truck (LT) tires on. I’m pretty sure tires with recommended psi of 35 are passenger tires. You need LT tires with a load rating of D or E with the size trailer you have. Those load rating correspond to the number of plys in the tire. Two plys for very letter. Load rating D=8 plys, E=10 plys.

Passenger car tires aren’t made to carry the weight of a heavy trailer, LT tires are.

On my tires, it says LT before the tire size.

Added-the higher the load rating, the more air you can put in. It’s the higher PSI that enables you to carry more weight. That is why you have heard it’s better to have more air in your tires when you are towing.

[sourdough]

New to all this have a question about tire psi my truck says max 35 psi but heard to put more while towing can any body help me out on whats good...?


You're pulling a 9400 lb. gvw trailer. Those tires (P rated 4 plys) should be inflated to the max pressure (51psi). At that pressure the tire is rated to carry approx. 2535 lbs. depending on brand. Figure you could be carrying close to 3000 lbs. weight on the rear axle when empty then dropping 11-1200 of tongue weight on it then add a load to the truck....you could possibly (maybe easily) exceed the max rating for the tires. Not good, even dangerous. Remember the soft sidewalls of such a "soft" tire will flex like crazy with that kind of load on it.

If it were me, I wouldn't worry about what psi to run in those tires, I would pull them off and put on LTs.....along with air bags and upgraded shocks (you're running an F150 if I recall). You've got too much trailer for the truck, much less the tires IMO.

Edit: Here's a link to a Hankook page for that size tire - first one that came up and didn't know your brand. Note the ply/weight rating for your current size tire (4/113).

https://www.hankooktire.com/us/passenger-cars/hankook-dynapro-at-m-rf10.html

[CWtheMan]

And the tire says 51psi

Those are passenger metric tires. Take the maximum load capacity they will provide from the chart and divide it by 1.1. That will provide you with their maximum load capacity for service on a pick-up truck (2304# per tire).

When towing a trailer I recommend using the tire's maximum allowed inflation pressure found on the tire sidewall (51 PSI) . It WILL NOT increase the tire's load capacity but will stiffen the sidewalls for a firmer ride.

You cannot overload those tires without overloading the vehicle or vehicle GAWRs. They couldn't put them on there if they could not carry the truck's designed maximum load capacity.

[Cfitzkp]

Gawr says 3800#
Got to check tire later for what it says but ur saying to inflate to 51psi?

[CWtheMan]

Gawr says 3800#
Got to check tire later for what it says but ur saying to inflate to 51psi?

Just for towing. For normal day to day operation use the vehicle manufacturer recommendations.

[Logan X]

I think the concern we had about using LT tires instead of passenger, or P, tires is the size of your trailer. I think with the size trailer your have you will be in danger of exceeding your rear axle weight and your tires load carrying capacity. One way to help mitigate the danger of towing overloaded is to upgrade tires to LT tires. Of course, I am not suggesting you should tow overweight.

The only way to know for sure if you are overweight or not is to load up everything and go to a scale.

If you do tow on P tires, which I think is a bad idea, they should be aired to the max inflation listed on the side of the tire.

[Tireman9]

New to all this have a question about tire psi my truck says max 35 psi but heard to put more while towing can any body help me out on whats good...?


Your truck owner's manual has a section on tires and proper inflation. Many trucks have two ratings "low load" or Empty and Heavy load or fully loaded (when you are towing)


Your inflation placard (you do know where that is) may also have that info.

[Tireman9]

You're pulling a 9400 lb. gvw trailer. Those tires (P rated 4 plys) should be inflated to the max pressure (51psi). At that pressure the tire is rated to carry approx. 2535 lbs. depending on brand. Figure you could be carrying close to 3000 lbs. weight on the rear axle when empty then dropping 11-1200 of tongue weight on it then add a load to the truck....you could possibly (maybe easily) exceed the max rating for the tires. Not good, even dangerous. Remember the soft sidewalls of such a "soft" tire will flex like crazy with that kind of load on it.

If it were me, I wouldn't worry about what psi to run in those tires, I would pull them off and put on LTs.....along with air bags and upgraded shocks (you're running an F150 if I recall). You've got too much trailer for the truck, much less the tires IMO.

Edit: Here's a link to a Hankook page for that size tire - first one that came up and didn't know your brand. Note the ply/weight rating for your current size tire (4/113).

https://www.hankooktire.com/us/passenger-cars/hankook-dynapro-at-m-rf10.html


Even going to LT tires may not be what he needs. The GCWR ( Gross Combined Weight Rating) total for the GVWR of the truck and GVWR of the trailer MUST be below the GCWR. I doubt that either the RV sales person or truck sales person bothered to provide that info as they were probably afraid they might lose the sale by saying that he needs a bigger ($$$) truck or smaller trailer.

The vehicle placards (certification labless) that we have been talking about providethis critical inofrmation. I bet noone pointed them out or told Cfitzkp (http://www.keystoneforums.com/forums/member.php?u=29544) how inportant those numbers were.

[Logan X]

The vehicle placards (certification labless) that we have been talking about providethis critical inofrmation. I bet noone pointed them out or told Cfitzkp (http://www.keystoneforums.com/forums/member.php?u=29544) how inportant those numbers were.

I think this was addressed at length in another post.


http://www.keystoneforums.com/forums/showthread.php?t=37700

[Tireman9]

Here is info showing how to learn if yortruck is big enough to tow and to stop safely.


https://rvsafety.com/rv-education/matching-trucks-to-trailers


Lot of posts addressing tires, but as tire engineer I know that tires alone are not the limiting factor. Don't go and buy tires only to discover a few weeks later you really need a new truck.


I will bet a coffee the F150 is not rated to pull a 9,000# trailer, especially if you haave stuff in the truck.

[jadatis]

Assuming 3800 lbs is gawr rear, you are not allowed to go over that.
Then calculated that 29 psi carries that 3800lbs +10% ( to cover unequall loading R/L)
The 35 psi is a general advice for P tires, knowing that rear axle is often overloaded when towing.
The 51 psi is the max allowed cold pressure.
The difference between 35 referencepressure and maxcold is used to highen up 35 psi for speed above 99mph, and camber angle more then 2 degr ( wheels like this on axle /-\ instead of this |-| ).
If its a european metric tire referencepressure is 36 psi, and european ETRTO never used maxload/ 1.1 for normal car tyres for SUV MPV or whatever.

So no, if you dont drive faster then 99mph or camber angle above 2, you dont need to go higher then 35 psi for rear, and front does not get more weight on axle when towing, sooner less, because of leaver effect, so certainly no higher pressure needed.

Googled your sise 275/55R20 and XL has loadindex 117 so your 113 must be a standard load tire wich carries its maxload of 2540 lbs AT 35 ( USA P in front of sises) or AT 36 psi ( EUR Nothing in front if sises) . For that info , look at sidewall.