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Old 10-09-2012, 10:07 PM   #1
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Weighed the RV and what Tire Pressure?

As my Rving experience grows and that I start to learn more and more because of IRV2, it all brings me to ask a question.

My RV pictured below is a single wheel in front and rear and today I had it weighed. The GVWR is 10,400 and it currently weighs 4,300 lbs on the front and 4,900 on the rear.

I estimate that I will be adding another 8-900 lbs when I get here ready to travel... EX: full tank of gas, 25 gallons of water, 100 lbs of black water, 300-400 lbs of personal belongings etc....

My loaded weight should be @ 4,700 for the front and 5,400 for the rear for a total of 10,100 total. Pretty close to the GVWR weight of 10,400 lbs.

My tires are single LT245/75/16's and I couldn't find a Tire Pressure chart for Hankook tires but I notice that Michelin and Goodyear seem to have the same charts. Since my tires are "Load E" type light truck tires should I base it on the Goodyear or Michelin tire charts?

From what I can tell from the tire charts, I would need @ 60 lbs in the front and @ 70 lbs in the rear. My Hankooks are printed on the sidewall, MAX 80 lbs for MAX load of 3042 lbs.

Does this make sense?
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Old 10-09-2012, 11:08 PM   #2
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Even after weighing it today (basically empty) the front axle is 4,300 lbs and the rear is 4,900 lbs. That means that I should be running 50 lbs in the front and 60 lbs in the rear.

That sounds kind of low, or am I reading the tire chart wrong?
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Old 10-09-2012, 11:27 PM   #3
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You need the pressure charts for the tires you have, not another brand. Doubtful that you need more pressure in the rears than the front. You have pretty close to the same weight front and rear but twice as many tires in the rear.
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Old 10-09-2012, 11:44 PM   #4
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You need the pressure charts for the tires you have, not another brand. Doubtful that you need more pressure in the rears than the front. You have pretty close to the same weight front and rear but twice as many tires in the rear.
I looked all over the Hankook site and never could find a tire pressure chart.

I have a single tire rear axle, not dual wheels. So I guess your statement of tire pressure for the rear doesn't hold up.

I am just trying to understand how much to inflate the tires to AND be safe at the same time.
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Old 10-09-2012, 11:48 PM   #5
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He only has singles on the rear.

You only have 6082 lbs tire capacity on each axle with what you have. I would be running the 80 psi since you are right at the tire weight limit. Next time you get tires I would also look at higher weight rated tires. The tires on my F350 are E rated but have a 3415 pound Max weight rating. Yours sound a lot like a D rated tire.
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Old 10-09-2012, 11:56 PM   #6
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He only has singles on the rear.

You only have 6082 lbs tire capacity on each axle with what you have. I would be running the 80 psi since you are right at the tire weight limit. Next time you get tires I would also look at higher weight rated tires. The tires on my F350 are E rated but have a 3415 pound Max weight rating. Yours sound a lot like a D rated tire.
I am confused here?

My current weight on the rear is 4,900 lbs but when I load up to go down south for the winter I estimate the rear should weigh @ 5,400 lbs on the whole axle.

Wouldn't that mean that 5,400 divided by 2 = 2,700 lbs

Doesn't that mean that I should be running @ 70 lbs?
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Old 10-10-2012, 12:05 AM   #7
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Originally Posted by imorton View Post
I am confused here?

My current weight on the rear is 4,900 lbs but when I load up to go down south for the winter I estimate the rear should weigh @ 5,400 lbs on the whole axle.

Wouldn't that mean that 5,400 divided by 2 = 2,700 lbs

Doesn't that mean that I should be running @ 70 lbs?
Sprdtyf350 is correct..

First, you dont really know what your loaded axle weights will be. They could be more. You also dont know if you have 200-400 more lbs on one side or the other.

Second, your estimate of 2700lbs puts you right at the weight rating for 70psi with no safety margin. And again, you dont know if you will have 2400lbs on one side, and 3000lbs on the other.

Third, we dont really know if 70psi is even correct for your tire brand. It could, and prolly is, different. I have posted before about the psi difference between Goodyear and Michelin and even Double Coin. Mr_D is correct in telling you to find the Hankook load inflation charts and use them.

So, given all three reasons, 80psi would be my answer to you.
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Old 10-10-2012, 12:12 AM   #8
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Sprdtyf350 is correct..

First, you dont really know what your loaded axle weights will be. They could be more. You also dont know if you have 200-400 more lbs on one side or they other.

Second, your estimate of 2700lbs puts you right at the weight rating for 70psi with no safety margin. And again, you dont know if you will have 2400lbs on one side, and 3000lbs on the other.

Third, we dont really know if 70psi is even correct for your tire brand. It could, and prolly is, different. I have posted before about the psi difference between Goodyear and Michelin and even Double Coin. Mr_D is correct in telling you to find the Hankook load inflation charts and use them.

So, given all three reasons, 80psi would be my answer to you.
Okay, I'm really confused...

If I look at the Michelin and Goodyear chart for a LT245/75/16 tire size and Load E rating. If I take my current weight today, wouldn't my pressure be the following ?

Front, 4300, 50 lbs
Rear, 4900, 60 lbs


Just trying to understand the tire pressure charts, IAN...
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Old 10-10-2012, 12:30 AM   #9
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Yes... but, to be safe due to not knowing what percentage of your axle weight is on which side, I (and most others) bump the psi up. I use an extra 10psi. So unloaded, I would use 60psi and 70psi, and when loaded for travel, I would go up to 80psi all around unless I knew for a fact what my corner weights were.

You could use 50/60 psi, or even up it by 5 to 55/65psi when unloaded, but I would seriously recommend you go to 80psi when loaded and traveling.
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Old 10-10-2012, 12:41 AM   #10
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Yes... but, to be safe due to not knowing what percentage of your axle weight is on which side, I (and most others) bump the psi up. I use an extra 10psi. So unloaded, I would use 60psi and 70psi, and when loaded for travel, I would go up to 80psi all around unless I knew for a fact what my corner weights were.

You could use 50/60 psi, or even up it by 5 to 55/65psi when unloaded, but I would seriously recommend you go to 80psi when loaded and traveling.
Hmmmm, I am starting to better understand all of this.

Unfortunately today when I went to a weigh scale, they can only weigh front or rear axles, they can weigh corners :(

So I think that I will run 55/65 lbs now, and at least 65/75 when loaded and traveling.

As soon as I am loaded for travel, I will try and find a CAT scale that can weigh my corners exactly and will review the tire chart to see what I need.

And depending on the corner weights I may very well run 65/75 or up it to 70/80

The front end wanders when running "over-inflated" but better than being under-inflated I guess

What's funny is that registration papers say that I weigh 8016 lbs and today with very little in the motorhome it weighs 9,200 lbs and I estimate it will go up to @ 10,100 when fully loaded for 6 months away.

Just food for thought.
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Old 10-10-2012, 12:59 AM   #11
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RV's are usually overloaded to start..

When you find your corner weights, make sure you inflate both sides of the axle for the tire with the highest load. ie: if you have 2600lbs on the left, and 2800lbs on the right, inflate both side to 75psi. Tires across axles must have the same psi.
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Old 10-10-2012, 01:15 AM   #12
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RV's are usually overloaded to start..

When you find your corner weights, make sure you inflate both sides of the axle for the tire with the highest load. ie: if you have 2600lbs on the left, and 2800lbs on the right, inflate both side to 75psi. Tires across axles must have the same psi.
That's good to know as I am sure there will be a variance between weights side to side
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Old 10-10-2012, 07:29 AM   #13
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When I weighed mine, at Escapees "Smart Weigh" individual tire weigh, I found out I was 300 Lbs different in the front and 600 Lbs different in the back on opposite corners. All within tire and axle ratings.

With this information, I was able to move stuff around and better balance the rig. It rides and corners better.
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Old 10-10-2012, 11:31 AM   #14
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When I weighed mine, at Escapees "Smart Weigh" individual tire weigh, I found out I was 300 Lbs different in the front and 600 Lbs different in the back on opposite corners. All within tire and axle ratings.

With this information, I was able to move stuff around and better balance the rig. It rides and corners better.
I wish I could find a place to weigh each corner. That would help me find the correct tire pressure.

At least today I finished installing new 4" brass valve stems... Now I can easily check or inflate them
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