Tire pressure on tow vehicle

[shmalik]

I have always inflated tires on the tow vehicle up to the maximum pressure indicated on the tires. A couple of days ago, while changing oil at the shop, I was told that I have to use numbers on the car (sticker on the door) to know how much air should be in the tires and not the numbers on the tire. The reason for that is because the tire manufacturer doesn’t know what vehicle tires are going to be mounted on and just show a ‘generic’ number.
In my case, the tires say it should be 44 PSI, the sticker on the car indicates 32(front)/ 36(rear). Big difference….
So, who is right and who is wrong? Should I use numbers on the tires or on the car?

BTW, I inflate the trailer tires to the maximum cold PSI shown on tires (which I think is 50) Is it correct?

 

[tommays]

Re: Tire pressure on tow vehicle

IMHP the pressure rateing on the tow vehicle is a comprise between ride comfort , load AND type of vehicle

My Silverado has 44# tires and is very happy at 40# + presssure on the other hand are Equniox also has 17" 44 psi tires and gives a very bad ride if you go much above the pressure 34 to 36# in the owners manual and can get bouncey to the point of causeing saftey problems


The trailer tires should allways be run at there max pressure

Tommays

 

[JB]

Re: Tire pressure on tow vehicle

The pressures shown in the door jamb of your vehicle are calculated to match the weight and suspension. After all, the tires are part of the suspension and the rest of the suspension is calibrated for those pressures.

Use the pressures the vehicle asks for.

As Tom says, always inflate trailer tires to the spec on the tires.

 

[Silvertip]

Re: Tire pressure on tow vehicle

Some vehicles post two tire pressures. One for average load and one for maximum load. It isn't always the tires that limits maximum load. The suspension system itself in some cases determines maximum load. In other words, you can put tires on a vehicle will carry far more weight than the suspension system can handle. As others have indicated -- use the tire pressures indicated on the label.

 

[DJ]

Re: Tire pressure on tow vehicle

The vehicle sticker is the one to go by.

You are correct in assuming that the tire mfg. rates the tire at a MAX. pressure.

Go with the vehicle mfg. rating.

 

[shmalik]

Re: Tire pressure on tow vehicle

Thank you all for the replies.

 

[aggiedave98]

Re: Tire pressure on tow vehicle

just to reiterate a point (but not to say that I know the right answer)... my trailer tires say 50psi max but my trailer says to use 40 I think...

but the key is that tires say MAX so for a trailer, I say, go by the label on the trailer (where the VIN is).

if you are using stock size tires on your tow vehicle, use the door jamb info...

just my opinion, not a tire pro...

 

[bruceb58]

Re: Tire pressure on tow vehicle

Tire pressure is calculated by the vehicle manufacturers using load, handling characteristics, suspension design, tire wear, etc to come up with the tire pressure. When you are fully loaded with trailer tongue weight and extra load in the back of the vehicle, it is possible that you have added hundrefds of pounds to the weight carried by the rear tires. It is absolutely necessary to increase the air pressure under those circumstances.