Appropriate Tire Pressure?

rvnetter wrote:
I have a 25' Class B+ motorhome. It has 16", Load E tires rated at 80psi cold. Is it safe to run them anywhere between 65psi - 80psi cold? I currently have them inflated at 70 psi, we have an average load, with 2 adults.

Thanks for your input

To be safe, I would contact the Motorhome manufacturer for what they recommend and double check with the tire manufacturer.

Whatever the Chassis manufacturer (Ford? Chevy?) sticker in the door jamb says, is THE MAX. That is almost certainly less than the 80 PSI on the sidewall of a Load Range E tire.

Weighing your coach, as ready for travel (people, supplies, stuff all on board) at a truck stop or other scale is best. Than adjust pressure according to a Load/Pressure chart. Adjust again once the tires are cold. Michelin's chart is easy to find. You can use that chart for Michelin or other brands, as long as the specs of the tires are the same.

If you tow a car, have it behind you at the truck stop CAT scale. It'll give your Front Axle as "Steer", Rear Axle as "Drive" and Car as "Trailer."

We have a 21' C. Probably the same tire size as yours. Max on tires is 80.
The door jamb from camper company states 55 all the way around. We run 60 on all
and seems to be fine.
Brian

Weight at a truck stop, quarry, landfill, feed mill, etc.
Use the manufacturer's load inflation table for your tires to determine the proper inflation pressure for the weight they are carrying. That's really the only way to do it.

Most any truck stop has scales. You could also look for a closed highway DOT scale. I use them often, around here even closed the scales are still on.

Where can one go to get your unit weighed?

We have a 24 foot Class C on the E450 chassis with Michelin Load Range E tires on it (maximum of 80 lbs. pressure - as printed on the sidewalls).

I have used 75-80 lbs. of pressure in the rear tires and 60-65 lbs. of pressure in the front tires for years, and it has always handled "like a van". Too much pressure in the front tires can cause the motorhome to feel like it's wandering when going down the road ... which wears you out steering it. 60-65 lbs. in the front for us has not caused this affect.

I like fairly high pressure in all the tires (without affecting steering) regardless of going over what weight charts might recommend - so as to keep sidewall flexing and the resulting heating of the tire material to a minimum for long tire life.

However, maximum or near-maximum tire pressure in the rear tires does make for a stiffer ride in the rear on an under-loaded E350 or under-loaded E450 Ford Class C chassis. To help with this I've replaced the stock rear shocks with specific after-market shock absorbers that were not available until several years after we had bought our motorhome.

Guessing could be harmful to not only the tires but your safety. I suggest As donn0128 has said, need to weigh it as your normal travel mode to determine what air pressures you need to have in your tires.

Without actual 4 corner weights your only guessing. Guessing toward safety you should have them inflated to the maximum pressure as listed on the sidewalls.