help me understand

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danford50

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North Carolina
I had my motorhome weight and here are the weigh steer axle 4320 and drive axle 7920,  the steer axle is which tires front or rear, and the drive axle is which tires front or rear, I am trying to figure out the weigh for each axles. according to the placard on the door jam the front axle is 5000 and the rear 9600, my weigh that I have are they within tolerance, if so should I put in the amount of air base on the placard.
 
The "steer" axle is the front axle, the one you steer with. So you're allowed 5,000 and have 4,320 -- sounds fine to me. The drive axle (wheels that provide propulsion) generally have the heavier load, and you're allowed 9,600 but have 7,920. Sounds fine.

But the other question that must be asked is, "Was this loaded for camping or was it with an empty rig?" It makes a difference.
 
An easy way to think of Drive and Steer axles is this

The Steering wheel operates the Steer axle

THe Engine the Drive Axle

DO NOT READ THE REST OF THIS LINE: And yes. on cars with Front wheel drive. Same axle

There are exceptions but not in the RV world
 
John From Detroit said:
An easy way to think of Drive and Steer axles is this

The Steering wheel operates the Steer axle

THe Engine the Drive Axle

DO NOT READ THE REST OF THIS LINE: And yes. on cars with Front wheel drive. Same axle

There are exceptions but not in the RV world

Even in the RV world, are exceptions:
http://www.gmcers.org/

 
John From Detroit said:
There are exceptions but not in the RV world

In the RV world there was the GMC and Revcon Class A motorhomes that used front wheel drive...so there is exceptions in RV's.


... as to the amount of air in the tires,  he should just go by the door tag for the recommended amount of air pressure regardless of the actual weights .
 
Be sure that the tires on your vehicle at least match the tire size and load rating listed on the placard. I know it's an RV but I've seen people at our shop running different sized tires than listed as OEM on the placard, usually in a positive direction, but a few have gone the other way with smaller, less load rated tires. Like 4 ply tires on a diesel truck.
 
looking at the Michelin tire chart for my size of tires which is LT 225-75-16 load range E, base on that chart for the front I should have 60 psi and for the rear I should have 60 psi also.
 
danford50 said:
looking at the Michelin tire chart for my size of tires which is LT 225-75-16 load range E, base on that chart for the front I should have 60 psi and for the rear I should have 60 psi also.
And I bet you will be amazed at how much better your RV handles once you get the tire pressure set correctly.
 
SeilerBird said:
And I bet you will be amazed at how much better your RV handles once you get the tire pressure set correctly.

I bet the door jam information says 75 in front and 80 in the rear.  Why in the world would you run 60#???????
 
GaryA said:
If the mfg recommendation is 60 it must be for something other than a heavy motorhome.
The manufacturers recommendation is because that is the proper air pressure for the weight of the motorhome. Read this article and it will answer all your questions.

https://www.thefitrv.com/rv-tips/how-to-set-the-tire-pressure-in-your-rv/
 
GaryA said:
If the mfg recommendation is 60 it must be for something other than a heavy motorhome.

Which means it would be lighter weight. The tire manufacturer's tables are calculated for a specific amount of weight on the axle, not caring if it's a truck, RV or railroad car. It's not a one-size-fits-all figure, but rather a table with a specific range of weight vs pressure. Note on this Michelin page that it is laid out by tire size (19.5" 22.5", etc.), by model of tire (XZE, XRV, etc.), and by single tire or dual tires, each table having pressure vs. weight. The tire obviously doesn't ""know" what's causing that weight (nor "care"), but physics cause it to react according to the various forces applied to it, which are strongly affected by weight and psi of pressure.

These tables are the tire manufacturer's way of saying, "This is how we've designed the tire to operate."

Note that these tables also show you the "Maximum load & pressure on sidewall" figure that is imprinted on that sidewall, the same as the highest weight rating for a SINGLE in the table, and so it shows that tires are NOT designed to have only a single pressure under all circumstances.
 
however I do not carry water and my fuel was about 3/4 full and we always pack light, the max weight for my motorhome is 14500
 
According to Michelin, the difference between 60# (which I understand to be your "nothing loaded" weight) and 75# in your ties is 2,020 pounds.  2 adults,  groceries, stuff in the storage areas, propane, gas, fresh water??????????????????  Anyone's guess until you weigh it loaded as you would when you hit the road.
 

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