Chassis weight and tires

[edge68474]

I am starting to get things somewhat organized with my MH as far as weight and tire pressures. My chassis is rated at 20,500. Just for drill, we went down to the scales close by here and weighed it. Nothing loaded up yet, just wanted an idea about it's weight, total, 17700. so we have about 2800 to max out the chassis.
Now my tires are good for 9800 on the front, and 17200 on the back.
4940lbs. @ 120 psi X 2=9800
4300 lbs. @ 110 psi X 4+17200
For a total of 27,080.
My question is, what determines how much weight the chassis can carry?
Are some frames made of thicker steel etc. etc.?
I don't think I would load as much as I'm allowed right now, 2800 lbs. of gear, food and so on.
Why couldn't I max out to say 25,000 lbs., if the tires can take it?
Just thinking. Maybe I should stop that, lol. Sorry, I can't help it

[rk911]

what were your individual axle weights? that's what counts. when you weighed were your fuel, fresh and LP tanks full? gas = 6-lbs per gallon; water = 8-lbs per gallon; LP = 4-lbs per gall (all approx. weights). doesn't sound like your coach was loaded as it would be for travel.

until you establish a baseline for each axle you won't know how much weight you can add to that axle. it IS possible to be underweight on the front, overweight on the rear and still show as weighing less than the GVWR. I know from personal experience.

when we took delivery of our new MH in 2015 all of the tanks save the fuel was empty and that was approx. 1/4-full. one of the first things I did was to get it weighed (all weights done were individual axle weights). I called that my 'empty weight'. next I filled the fresh water, fuel and LP tanks and re-weighed. that was my 'wet weight'. finally, I loaded her up for a trip...food, supplies, clothing, passengers, pets and other 'stuff' and re-weighed. that was my 'traveling weight'. since the empty and wet weights are baselines I plan to repeat the traveling weight every couple of years. 'stuff' does increase to fit the space available.

once you know your 'traveling weight' you can properly inflate your tires.

good luck!

[Jthigh]

Manufacturers (Ford or Chevy) set the GVWR based on the load rating of springs, frame suspension, and more importantly braking stop distance. As chassis ratings increase certain components (like brakes) are sized accordingly.

[FastEagle]

Originally Posted by edge68474

I am starting to get things somewhat organized with my MH as far as weight and tire pressures. My chassis is rated at 20,500. Just for drill, we went down to the scales close by here and weighed it. Nothing loaded up yet, just wanted an idea about it's weight, total, 17700. so we have about 2800 to max out the chassis.
Now my tires are good for 9800 on the front, and 17200 on the back.
4940lbs. @ 120 psi X 2=9800
4300 lbs. @ 110 psi X 4+17200
For a total of 27,080.
My question is, what determines how much weight the chassis can carry?

It's manufacturer will set it's cargo capacity before delivery to the dealer/consumer. Anything added - weight - options - must be deducted from the manufacturer's cargo figure.

Are some frames made of thicker steel etc. etc.?
I don't think I would load as much as I'm allowed right now, 2800 lbs. of gear, food and so on.
Why couldn't I max out to say 25,000 lbs., if the tires can take it?
Just thinking. Maybe I should stop that, lol. Sorry, I can't help it

GVWR (gross vehicle weight rating) The maximum permissible weight of the fully loaded motorhome, including liquids, passengers and cargo. The GVWR is equal to or greater than the sum of the unloaded vehicle weight (UVW) plus the net carrying capacity (NCC).

[edge68474]

Originally Posted by Jthigh

Manufacturers (Ford or Chevy) set the GVWR based on the load rating of springs, frame suspension, and more importantly braking stop distance. As chassis ratings increase certain components (like brakes) are sized accordingly.

Thank you John. You answered my question. All the other stuff I know about.
I'm sorry, my axel weights were,
Front, 6280
Rear, 11420, =17700
Rich. I like the three weight idea. Empty, Wet, and Travel
Thanks for your responses.

[l1v3fr33ord1]

Larry-

Our coach is a one-year-older "cousin" to yours. Last April we had a four-corner weigh (RVSEF, link here), with these results:

Front axle: 6,350 pounds (Rating 7,500 pounds)
Rear axle: 13,350 pounds (Rating 13,500 pounds)

This was with most of the five tanks (LP, grey, black, fresh and gas) over half full.

I have since moved some loads from rear to front, and left some stuff at home. I have also adjusted tire pressures to suit.

This will give you an idea of where your loaded weights may come out.

[edge68474]

Very good Mark. Thanks for that info. Very much appreciated.