Tire Pressure

[Goldscooby]

Neal, I didn't know where to put this thread, so please put it in the right area. I wanted to check with all you experienced RVers out there. I have some wonderful Hankook tires on my Class C that the maximum pressure says 80 PSI. I measured all my tires and they come in at 65 PSI. (Well actually one was actually 80 PSI) My question is, am I running to low on tire pressure or am I good? I know you gain a couple pounds when moving and the tires get hot. I have heard all sorts of opinions on this but I would really like everyone's opinions here. Thanks Again!!!

John

2018 Thor Motor Coach Four Winds 30D
2020 Jeep Trailhawk (Toad)

 

[TJ&LadyDi]

Have you weighed your coach to get the corner weights? If so, have you then looked at the Hankook tire pressure chart to determine the inflation pressure for the corner weight? https://www.rvsafety.com/images/pdf/hankookinflationtable2019.pdf

If you haven’t weighed your coach, you have two options: (a) weigh the coach and use the Hankook chart to determine the appropriate pressure or (b) run the pressure listed on the chart posted in your coach by the manufacturer (it is usually near the driver seat or entrance door). Proper tire inflation is important and following the tire manufacturer’s (or coach manufacturer’s) recommendation is important.

For more information on this, use the RVF search took to look for “tire pressure.”

TJ

 

[Goldscooby]

TJ,

Once again I appreciate your answer which makes a lot of sense. Thanks Again!!

John

2018 Thor Motor Coach Four Winds 30D
2020 Jeep Trailhawk (Toad)

 

[Bob K4TAX]

The door sticker and the Owner Manual should give the proper tire inflation pressure for the vehicle. This is for the vehicle loaded to the maximum cargo weight. This is always below the maximum inflation pressure stated on the side of the tires.
Thus, I find no reason to use any other tire pressure. Increasing tire pressure does not increase the maximum cargo weight for the vehicle. There are two pressure specifications, vehicle, and tire. The vehicle spec is always less and supersedes the tire specification.

 

[hawlguy]

Door sticker is good if you are running original OEM tires or equivalent. However, if you change/upgrade your tires, then go by imprinted tire psi info, not the door sticker. The cold psi rating gives you the load carrying capacity the tire was designed for.

 

[Joe Hogan]

Gross Vehicle Weight Rating: How It Applies To Our Need For Aftermarket Access

Gross Vehicle Weight Rating: How to get your motorhome weight under control for your chosen lifestyle.

www.class-c-motorhome-info-made-simple.com

 

[Bob K4TAX]

Door sticker is good if you are running original OEM tires or equivalent. However, if you change/upgrade your tires, then go by imprinted tire psi info, not the door sticker. The cold psi rating gives you the load carrying capacity the tire was designed for.

I don't agree. There is nothing wrong with upgrading tires for a better ride, better handling, better traction, or longer tire wear. But in the end, the vehicle cargo rating is based on structural design, brakes, suspension, transmission, rear end, and other factors. This is on the placard on the driver-side door. Changing tires does not change vehicle cargo rating. Tire pressure stated on the sidewall is related to the maximum load for the tire, not the vehicle. The two are very different.

 

[hawlguy]

I don't agree. There is nothing wrong with upgrading tires for a better ride, better handling, better traction, or longer tire wear. But in the end, the vehicle cargo rating is based on structural design, brakes, suspension, transmission, rear end, and other factors. This is on the placard on the driver-side door. Changing tires does not change vehicle cargo rating. Tire pressure stated on the sidewall is related to the maximum load for the tire, not the vehicle. The two are very different.

I will agree with you to a point. However I bet you go by the payload rating no matter what, even though Ford derated the f250 to 10k gvwr for marketing/registration advantage. Exact same truck as f350 with one less leave spring. Common sense has been replaced by liability lawyers and marketing idiots. If mfg uses a 7400# rated axle with 20” wheels and tires at 3710# each, but limits payload to 2050lbs on door sticker due to derating, what’s the real capacity?

 

[Bob K4TAX]

I will agree with you to a point. However I bet you go by the payload rating no matter what, even though Ford derated the f250 to 10k gvwr for marketing/registration advantage. Exact same truck as f350 with one less leave spring. Common sense has been replaced by liability lawyers and marketing idiots. If mfg uses a 7400# rated axle with 20” wheels and tires at 3710# each, but limits payload to 2050lbs on door sticker due to derating, what’s the real capacity?

Agreed that is a numbers game with regard to marketing. However, should the vehicle have an issue while in warranty, if it is proven, due to modifications or overload, the warranty may not have to be honored. Likewise, if it is involved in an accident with loss of property or life, and it can be proven it was overloaded, the owner liability is valid.

Yes, I try very hard and with conscious efforts to operate within the specified limits. As a pilot, I understand the importance of weight and balance. Oh, there is a margin of safety, but as I heard an FAA examiner state; "exceed the gross take-off weight and one becomes a very underpaid test pilot." The same holds true with vehicles. I've seen more than one truck and trailer slide into or through an intersection.